From laser@mailman.qth.net  Mon Dec  1 11:00:43 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Mon, 1 Dec 2003 06:00:43 EST
Subject: [Laser] Digikey IR Laser.
Message-ID: <118.2c5b1794.2cfc795b@aol.com>

Hi group.

A few months ago someone mentioned the 120mW IR laser available from digikey 
at $20 (ish)

I was going to order one, but wondered if anyone in the group has used one of 
these devices and has any practical tips.

e.g.
What's the supply current to output power response like?

Is the standard brass housing large enough to dissipate the heat from a 120mW 
diode or should I be looking at mounting it in a large heatsink?

It's the first time I'll have used IR.  Does anyone know if a typical digital 
camera LCD for monitoring my attempts to focus the optics.

Finally, I realise that 120mW is dangerous..........I plan to use a 50mm dia 
lens with a short focal length to produce a beam that's somewhere between 30 
and 50mm dia. Hopefully this will be a safe level of 'power density'.  If the 
diode has a divergence of 30 degrees, then a convex lens of about 25mm focal 
length should do the job.
Now to find the best material for the wavelength......

Thanks.

If it all works I'll write up the results on my laser pages.


David    G0MRF              <A HREF="www.g0mrf.freeserve.co.uk">www.g0mrf.freeserve.co.uk</A>


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From laser@mailman.qth.net  Mon Dec  1 15:46:03 2003
From: laser@mailman.qth.net (Andrew T. Flowers, K0SM)
Date: Mon, 01 Dec 2003 10:46:03 -0500
Subject: [Laser] Digikey IR Laser.
References: <118.2c5b1794.2cfc795b@aol.com>
Message-ID: <3FCB623B.8040905@alltel.net>

David,

I have a couple of those wired up in my expanders and running into a 
10mm lens.  I don't have any way to measure output power right now, so 
I'm keeping current a bit below I(op) to be safe.  I'm not really 
concerned with linearity in my system, but I can tell you that the 
active current region for these devices is something like 50-150ma, so 
you have alot of room to play.  They don't even come with a feedback PD, 
so it's just assumed that you set it and forget it.  I'd like to try 
some troposcatter stuff once I get back to Nebraska this month (clear 
sky, one farmlight every mile or so) and it would be since to have some 
measurement of power output-I don't expect it to be the same at -10C as 
it is in my apartment :-) If anyone knows how to get a rough power 
measurement with out spending big $$$ I'd like to hear it.

I built my expander out of a few sections of PVC and utilized the 5-10cm 
adapter/lens/housing unit that is also on digikey's site.  That seems to 
be enough to keep it cool--mind you I'm running it at  a little below 
I(op) at 50% duty cycle, but it doesn't really get warm.  Anyway, this 
all results in a well collimated "rectangle" of light about 7-8cm long. 
 I used my computer's quickcam to do some alignement--I know it's not 
optimal, but it's good enough until I can borrow a decent camcorder or 
something witha zoom feature.

 I have a schematic of the expander and other laser stuff on my webpage:

http://mail.rochester.edu/~af006m/laser.html

Andy K0SM/2

G0MRF@aol.com wrote:

>Hi group.
>
>A few months ago someone mentioned the 120mW IR laser available from digikey 
>at $20 (ish)
>
>I was going to order one, but wondered if anyone in the group has used one of 
>these devices and has any practical tips.
>
>e.g.
>What's the supply current to output power response like?
>
>Is the standard brass housing large enough to dissipate the heat from a 120mW 
>diode or should I be looking at mounting it in a large heatsink?
>
>It's the first time I'll have used IR.  Does anyone know if a typical digital 
>camera LCD for monitoring my attempts to focus the optics.
>
>Finally, I realise that 120mW is dangerous..........I plan to use a 50mm dia 
>lens with a short focal length to produce a beam that's somewhere between 30 
>and 50mm dia. Hopefully this will be a safe level of 'power density'.  If the 
>diode has a divergence of 30 degrees, then a convex lens of about 25mm focal 
>length should do the job.
>Now to find the best material for the wavelength......
>
>Thanks.
>
>If it all works I'll write up the results on my laser pages.
>
>
>David    G0MRF              <A HREF="www.g0mrf.freeserve.co.uk">www.g0mrf.freeserve.co.uk</A>
>
>
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>to post in Plain-Text go to: http://www.expita.com/nomime.html  ---
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From laser@mailman.qth.net  Mon Dec  1 18:46:24 2003
From: laser@mailman.qth.net (Walt Rauscher)
Date: Mon, 1 Dec 2003 13:46:24 -0500
Subject: [Laser] Digikey IR Laser.
In-Reply-To: <3FCB623B.8040905@alltel.net>
Message-ID: <OIEHJKEDHIBNLBDJKOGNAEMLCBAA.wrauscher@gamry.com>

	A "relative" power monator is easy to put together. Just back-bias a
photodiode
and measure the voltage drop across the resistor. See Sam's Laser pages for
more info.
This is good enough for relative comparisions.
	On the subject of CCD cameras: the cheaper ones may be better for IR work
as they do not have an IR blocking filter. The more expensive ones do. If
you are out buying, take an IR LED and battery to test the camera.
	I've been experimenting with IR laser diode from CD players. They're cheap
(free). I'm also interested in cloud bounce/tropo scatter commuications.
Would like to make contest contacts without having to be Line-of-sight.

best to all,
walt, N3EVV

-----Original Message-----
From: laser-admin@mailman.qth.net [mailto:laser-admin@mailman.qth.net]On
Behalf Of Andrew T. Flowers, K0SM
Sent: Monday, December 01, 2003 10:46 AM
To: laser@mailman.qth.net
Subject: Re: [Laser] Digikey IR Laser.


David,

I have a couple of those wired up in my expanders and running into a
10mm lens.  I don't have any way to measure output power right now, so
I'm keeping current a bit below I(op) to be safe.  I'm not really
concerned with linearity in my system, but I can tell you that the
active current region for these devices is something like 50-150ma, so
you have alot of room to play.  They don't even come with a feedback PD,
so it's just assumed that you set it and forget it.  I'd like to try
some troposcatter stuff once I get back to Nebraska this month (clear
sky, one farmlight every mile or so) and it would be since to have some
measurement of power output-I don't expect it to be the same at -10C as
it is in my apartment :-) If anyone knows how to get a rough power
measurement with out spending big $$$ I'd like to hear it.

I built my expander out of a few sections of PVC and utilized the 5-10cm
adapter/lens/housing unit that is also on digikey's site.  That seems to
be enough to keep it cool--mind you I'm running it at  a little below
I(op) at 50% duty cycle, but it doesn't really get warm.  Anyway, this
all results in a well collimated "rectangle" of light about 7-8cm long.
 I used my computer's quickcam to do some alignement--I know it's not
optimal, but it's good enough until I can borrow a decent camcorder or
something witha zoom feature.

 I have a schematic of the expander and other laser stuff on my webpage:

http://mail.rochester.edu/~af006m/laser.html

Andy K0SM/2

G0MRF@aol.com wrote:

>Hi group.
>
>A few months ago someone mentioned the 120mW IR laser available from
digikey
>at $20 (ish)
>
>I was going to order one, but wondered if anyone in the group has used one
of
>these devices and has any practical tips.
>
>e.g.
>What's the supply current to output power response like?
>
>Is the standard brass housing large enough to dissipate the heat from a
120mW
>diode or should I be looking at mounting it in a large heatsink?
>
>It's the first time I'll have used IR.  Does anyone know if a typical
digital
>camera LCD for monitoring my attempts to focus the optics.
>
>Finally, I realise that 120mW is dangerous..........I plan to use a 50mm
dia
>lens with a short focal length to produce a beam that's somewhere between
30
>and 50mm dia. Hopefully this will be a safe level of 'power density'.  If
the
>diode has a divergence of 30 degrees, then a convex lens of about 25mm
focal
>length should do the job.
>Now to find the best material for the wavelength......
>
>Thanks.
>
>If it all works I'll write up the results on my laser pages.
>
>
>David    G0MRF              <A
HREF="www.g0mrf.freeserve.co.uk">www.g0mrf.freeserve.co.uk</A>
>
>
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From laser@mailman.qth.net  Mon Dec  1 19:31:34 2003
From: laser@mailman.qth.net (Jim Moss)
Date: Mon, 1 Dec 2003 11:31:34 -0800 (PST)
Subject: [Laser] Robert in Michigan looking for scatter partners
Message-ID: <20031201193134.61704.qmail@web80409.mail.yahoo.com>

Here is a note from Robert. He can't currently subscribe.

Please contact him direct.

 

Jim,

Thanks for the additional info on the problem. I've contacted our ISP about

the reverse mapping issue and I hope it will be fixed soon.

In the meantime, I'm looking for people who are experimenting with laser

troposcatter -- in particular, I've been trying to find a valid email

address for K3PGP with little success.

Would it be possible for you to make mention of my email address, callsign

and interest in non-LOS laser communication on the list? I'd greatly

appreciate it if you could!

Thanks much.

73,

Robert

KC8UCH

rrochte@gpacademy.org




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From laser@mailman.qth.net  Tue Dec  2 03:10:26 2003
From: laser@mailman.qth.net (Andrew T. Flowers, K0SM)
Date: Mon, 01 Dec 2003 22:10:26 -0500
Subject: [Laser] weak signal RX?
Message-ID: <3FCC02A2.906@alltel.net>

Here's a use for all those makeup mirrors you have lying around.  I'll 
bet it would work great for laser troposcatter :-)

http://antwrp.gsfc.nasa.gov/apod/ap020906.html

Andy
K0SM/2


From laser@mailman.qth.net  Thu Dec  4 04:30:40 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Wed, 3 Dec 2003 23:30:40 EST
Subject: [Laser] Ramsey transmit to CdS
Message-ID: <47.36a1ee64.2d001270@aol.com>

I finally ran a test with my Ramsey LBC6 transmitter to the Cadmium Sulfide 
photo sensor that I used for my laser MCW demonstration.  Both units were hand 
held in a brightly lit room at a distance of about 30 feet.  The signal was 
cuting out do to the beam not staying on the sensor, and the audio seemed to 
lack the fidelity of the LBC6 receiver, but it did work.  I connected two 
batteries (3 volts) in series with the Cadmium Sulfide sensor (from a Radio Shack 
package of miscelaneous CdS sensors) and a 2000 ohm headset (that may be more 
than 50 years old).  No amplification, just the photo resistor varying the 
current through the headset.

The CdS sensor is mounted at the focal point of a 4 inch lens (all this in 
3.5 pound Quik container with a soup can bolted to its bottom  -  Did I mention 
that my granddaughter likes chocolate milk? ), but for this test, I think it 
would have worked better "barefoot".   The beam of light was only about 3/4 
inch diameter.  The difference in audio quality could be a poor frequency 
response of the light sensor, or the headset, or a false impression by me due to the 
broken signal, maybe the ambient light.

It seems to reinforce my opinion that the Ramsey PWM is being used as a means 
of amplitude modulation, much like PWM is used to control the speed of 
electric motors.

Hope all y'all had a good Thanksgiving.

James 
N5GUI

From laser@mailman.qth.net  Thu Dec  4 04:54:39 2003
From: laser@mailman.qth.net (J. Forster)
Date: Wed, 03 Dec 2003 23:54:39 -0500
Subject: [Laser] Ramsey transmit to CdS
References: <47.36a1ee64.2d001270@aol.com>
Message-ID: <3FCEBE0E.2E95AE3C@quik.com>

CdS cells are a poor choice for detecting modulation. They are slow, and the lower the
light level, the slower the reponse.

IMO, you'd be much better off with a photodiode, back biased to reduce the capacitance
of the diode (space charge layer) and an optical BP filter.

-John


From laser@mailman.qth.net  Thu Dec  4 06:16:35 2003
From: laser@mailman.qth.net (John Matz)
Date: Thu, 4 Dec 2003 00:16:35 -0600
Subject: [Laser] Ramsey transmit to CdS
References: <47.36a1ee64.2d001270@aol.com>
Message-ID: <002901c3ba2e$2c89dbc0$040110ac@dadsibm166>

Hi
That is exactly how PWM is used ... classically.  If you truly have a PWM
light source, and the PWM sampling frequency is above 8 khz or so, usually
16 or 20 khz, then the 0-4 khz band contains an exact copy of the sampled
audio source.  The photo detector should have a BW of at least 3-4 khz for
audio.
John Matz KB9II

----- Original Message -----
From: <TWOSIG@aol.com>
To: <laser@mailman.qth.net>
Sent: Wednesday, December 03, 2003 10:30 PM
Subject: [Laser] Ramsey transmit to CdS


> I finally ran a test with my Ramsey LBC6 transmitter to the Cadmium
Sulfide
> photo sensor that I used for my laser MCW demonstration.  Both units were
hand
> held in a brightly lit room at a distance of about 30 feet.  The signal
was
> cuting out do to the beam not staying on the sensor, and the audio seemed
to
> lack the fidelity of the LBC6 receiver, but it did work.  I connected two
> batteries (3 volts) in series with the Cadmium Sulfide sensor (from a
Radio Shack
> package of miscelaneous CdS sensors) and a 2000 ohm headset (that may be
more
> than 50 years old).  No amplification, just the photo resistor varying the
> current through the headset.
>
> The CdS sensor is mounted at the focal point of a 4 inch lens (all this in
> 3.5 pound Quik container with a soup can bolted to its bottom  -  Did I
mention
> that my granddaughter likes chocolate milk? ), but for this test, I think
it
> would have worked better "barefoot".   The beam of light was only about
3/4
> inch diameter.  The difference in audio quality could be a poor frequency
> response of the light sensor, or the headset, or a false impression by me
due to the
> broken signal, maybe the ambient light.
>
> It seems to reinforce my opinion that the Ramsey PWM is being used as a
means
> of amplitude modulation, much like PWM is used to control the speed of
> electric motors.
>
> Hope all y'all had a good Thanksgiving.
>
> James
> N5GUI
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
>


From laser@mailman.qth.net  Thu Dec  4 14:15:27 2003
From: laser@mailman.qth.net (Walt Rauscher)
Date: Thu, 4 Dec 2003 09:15:27 -0500
Subject: [Laser] Ramsey transmit to CdS
In-Reply-To: <002901c3ba2e$2c89dbc0$040110ac@dadsibm166>
Message-ID: <OIEHJKEDHIBNLBDJKOGNAENACBAA.wrauscher@gamry.com>

  Always like to know what people are experimenting with and the results.
Its also the adage of you don't know what might work until you try it.
  Another sensor that works well is a photo voltaic cell, the kind to make
electrity from sunlight. I had used them a few times in college Physics lab
as a light amplitude detector and use one plugged into a Radio Shack audio
ampifier box as a simple laser comm receiver (cw keyed 800Hz). The frequency
response is good and they have a large area. I believe that they do not have
the low dark current necessary for very weak signal detection. Might be
worth trying.
walt, N3EVV
http://mailman.qth.net/mailman/listinfo/laser


From laser@mailman.qth.net  Thu Dec  4 23:04:58 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Thu, 4 Dec 2003 18:04:58 EST
Subject: [Laser] Ramsey transmit to CdS
Message-ID: <7a.4c50186a.2d01179a@aol.com>

Thanks John

If I did not make it clear before, I had used the CdS sensor on some 
experiments a long while ago.  The transmitter for that was a laser pointer driven by 
a 555 oscillator at about 700 Hz.  I had previously demonstrated that the 
Ramsey LBC6 receiver will pick that signal up very well.  I just wanted to check 
the other arrangement.

On the other hand: Since a CdS sensor can be used in a bright room to detect 
voice modulation on a light beam, it could be used in a classroom 
demonstration.  They are cheap and easy to get.  I dare say that a 5th grade science class 
will not appreciate the significant advantages of a photodiode.

I was not aware that CdS had slower frequency response in low light levels.  
My previous experiment would have suggested that the reverse is true.  Can you 
explain why?

James
N5GUI



CdS cells are a poor choice for detecting modulation. They are slow, and the 
lower the
light level, the slower the reponse.

IMO, you'd be much better off with a photodiode, back biased to reduce the 
capacitance
of the diode (space charge layer) and an optical BP filter.

-John

From laser@mailman.qth.net  Thu Dec  4 23:27:44 2003
From: laser@mailman.qth.net (J. Forster)
Date: Thu, 04 Dec 2003 18:27:44 -0500
Subject: [Laser] Ramsey transmit to CdS
References: <7a.4c50186a.2d01179a@aol.com>
Message-ID: <3FCFC2F0.D233899A@quik.com>

TWOSIG@aol.com wrote:

> I was not aware that CdS had slower frequency response in low light levels.
> My previous experiment would have suggested that the reverse is true.  Can you
> explain why?
>
> James
> N5GUI

Not offhand. I remember it from an old Clairex application booklet. Try looking here:

http://www.clairex.com/datasheets/cl900_series.pdf

or email them a question.
-John


From laser@mailman.qth.net  Thu Dec  4 23:27:00 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Thu, 4 Dec 2003 18:27:00 EST
Subject: [Laser] Ramsey transmit to CdS
Message-ID: <157.29137e45.2d011cc4@aol.com>

Hmmmmm.   I don't quite understand the point you are making.   If I was 
sending a PWM signal at  2.4 GHz and my neighbor HAM is sending another at 2.4005 
GHz, I would expect to be able to separate the two signals.

With the detection scheme used on the Ramsey LBC6, if I am using a red laser 
and my neighbor is using a green one, I cannot tell the difference between the 
two.  For that matter, I cannot tell either from a light beam that uses an 
amplitude modulated current to control the brightness of a neon bulb.

Even if you use LEDs of the same color, the system response the same to one 
that is PWM with pulses at 20 KHz,  at 50 KHz, at 500 KHz.  And if you use the 
same percentage of modulation, you can make it "look" like an LED driven with 
an audio signal with a DC bias current.

I guess that I am really looking for a better detector system.  This works.  
It is (sorta) inexpensive.  And it is what I have.  I would like to know about 
more.

Thank you for your comments.

James
N5GUI


Hi
That is exactly how PWM is used ... classically.  If you truly have a PWM
light source, and the PWM sampling frequency is above 8 khz or so, usually
16 or 20 khz, then the 0-4 khz band contains an exact copy of the sampled
audio source.  The photo detector should have a BW of at least 3-4 khz for
audio.
John Matz KB9II

From laser@mailman.qth.net  Fri Dec  5 00:19:53 2003
From: laser@mailman.qth.net (J. Forster)
Date: Thu, 04 Dec 2003 19:19:53 -0500
Subject: [Laser] Ramsey transmit to CdS
References: <157.29137e45.2d011cc4@aol.com>
Message-ID: <3FCFCF29.312FCF79@quik.com>


TWOSIG@aol.com wrote:

> Hmmmmm.   I don't quite understand the point you are making.   If I was
> sending a PWM signal at  2.4 GHz and my neighbor HAM is sending another at 2.4005
> GHz, I would expect to be able to separate the two signals.
>
> With the detection scheme used on the Ramsey LBC6, if I am using a red laser
> and my neighbor is using a green one, I cannot tell the difference between the
> two.  For that matter, I cannot tell either from a light beam that uses an
> amplitude modulated current to control the brightness of a neon bulb.

If you want to separate the laser colors, use an optical BP filter.  That's the
carrier.

> Even if you use LEDs of the same color, the system response the same to one
> that is PWM with pulses at 20 KHz,  at 50 KHz, at 500 KHz.

Those would be sub-carriers.

> And if you use the
> same percentage of modulation, you can make it "look" like an LED driven with
> an audio signal with a DC bias current.

The problem is that your detector, the CdS, looks like a LP filter with a light level
dependent cutoff of a few Hz to a few 100s Hz. You can't get 20 HKz through it. The
data shows the long CdS response times.

> I guess that I am really looking for a better detector system.  This works.
> It is (sorta) inexpensive.  And it is what I have.  I would like to know about
> more.

Use a back-biased photodiode. Even a solar cell would work better.-J

> Thank you for your comments.
>
> James
> N5GUI
>
> Hi
> That is exactly how PWM is used ... classically.  If you truly have a PWM
> light source, and the PWM sampling frequency is above 8 khz or so, usually
> 16 or 20 khz, then the 0-4 khz band contains an exact copy of the sampled
> audio source.  The photo detector should have a BW of at least 3-4 khz for
> audio.
> John Matz KB9II

It's called 'the sampling theorem' You must sample at twice the maximum information
rate.-J



From laser@mailman.qth.net  Sat Dec 13 05:38:14 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Sat, 13 Dec 2003 00:38:14 EST
Subject: [Laser] halos, pillars, and lasercomm?
Message-ID: <12e.3766b9f9.2d0bffc6@aol.com>

I confess that I do not understand troposcater, less for light than uhf, but 
I have had some thoughts on light communication using clouds.  Below the idea 
is to use high thin ice crystal clouds, which are very common, for over the 
horizon communications.  For more information I suggest checking the atmospheric 
optics link on the web page for spaceweather, especially halos and pillars.  
(If I included the link, I don't think that my message would get past the spam 
filter.)

High thin clouds are often made of ice crystals in the form of hexagonal 
rods, some long and some short.  

The short ones seem to fall flat side down and are associated with weather 
phenomina called pillars and sun dogs.  A laser beam sent into such a cloud 
would be reflected with its energy distributed over an area that depends on the 
amount of wobble or tilt the crystal have.  The more wobble, the bigger the area 
of dispersion.  To use this for lasercomm, the geometry would be similar to a 
large horizontal mirror that reflects (less than 100%) and expands the beam 
(more wobble, more beam expansion).  Knowing the angle of the transmitted beam 
and the distance to cloud would allow calculation of the cloud height and the 
"footprint" of the reflected beam and approximate signal strength.  If the 
receive station is within the footprint, communication is possible.  The return 
path should be open, but I think that the signal strength will be better when 
the distance from the transmitter to the cloud is longer than the distance from 
the cloud to the receiver. 

The long hexagonal rods might also be used for lasercomm.  If the axis of the 
rod is perpendicular to the line of sight from the transmitter, the light 
striking one of the three faces toward the transmitter (ignore the other cases 
which are rare) will be refracted by an angle that is minumum 21.7 degrees and 
maximum 33.8 degrees (see the simulation on the formation of 22 degree ice 
halos).  Combine this with the skewing caused by crystals whose axies are not 
quite perpendicular to the line of sight from the transmitter and the result is 
another footprint with signal strength distribution.  There is a greater 
concentration of the light near the minimum refraction angle.  The 22 degree halos 
around the sun, (full or partial) are caused by this.  

Calculation of the geometry for the communication path using long hexagonal 
rods should be similar to the short rod example, but I expect three distinct 
differences.  

1.  The signal strength for the long rod best refraction directions should be 
less the short rod reflection best direction.  

2. The short rod has a single aim point above the line between the 
transmitter and the receiver, whereas the long rod geometry can use any aim point along 
an arc whose center is the transmitter to receiver line.  (The angle from 
transmitter to cloud to receiver will be close to 180 degrees minus 22 degrees, or 
158 degrees. )  

3.  The footprint of the short rod geometry is better for stable atmosphere, 
but should not affect the long rod case.  For short rods, the more wobble, the 
longer any given crystal will be away from the desired cone of best signal, 
but "wobble" for the other system will cause as many rods to go into the 
desired cone as out of it, because they were randomly arranged.


I imagine the equipment to use these clouds of crystals would be a 
transmitter that first serves as a LIDAR to get the range to the cloud crystals.  The 
azimuth and elevation angle of the beam combined with the range to the clouds 
and the location of the transmitter, would allow the computation of the 
footprint and signal strength estimates.  Slewing the direction of the transmitted 
beam would allow sending the best signal to the receiver as the conditions 
change.  If there is a similar system on the other end, and a liason communications 
link is available, it can be directed to the most probable direction of 
signal.  Once communication is established, if either system detects changing 
condition, it can send the information to the other side before it adjusts the 
transmit direction, reducing the need for separate liason.  Also, the receiver may 
need to be pointed independently.  The system could also be used to map the 
"real" signal strength compared to the predicted value.  In turn that can be 
used to improve the prediction.

Lots of things to work out for such a scheme -- field of view for the 
transmitter and receiver, can the LIDAR receiver be the same as the communication 
receiver, ........


I feel that the crystal would provide a stronger signal than troposcatter, 
but could be used less often.  The same equipment could be used for both, unless 
there are color advantages that I have not heard about.  It also seems that 
this system would provide interesting information on the ice crystals in the 
clouds at the same time it allows communication.

James
N5GUI


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From laser@mailman.qth.net  Sat Dec 13 05:38:19 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Sat, 13 Dec 2003 00:38:19 EST
Subject: [Laser] moon repeater
Message-ID: <1db.16785c74.2d0bffcb@aol.com>

This seems to be my night for wild ideas.  

I have heard a lot of news media chatter about the President announcing a 
bold new venture for NASA on the 100th anniversary of the Wright Brothers flight, 
next week.  What got my interest was returning to the Moon with a permanently 
manned base.  

If such a base was built and maintained, the chance for a system like ARISS 
could be added.  Then the system would be accessable whenever the moon is above 
the horizon instead of a few minutes at a time.  And gee, why not use a 
laser?  Ok, how big?  How to arrange the effort?

To simplify the idea, I limited the concept to a repeater.  There are passive 
and active repeaters.  The retro-reflectors left on the Moon by the Apollo 
program are passive repeaters, but are too small and too narrow.  A passive 
repeater would have to be large and allow a beam to expand to a large area on the 
return to Earth.  How large would depend on the power in the transmitted beam. 
 The expansion should be most of the earth to support EME.  For an active 
repeater, the receiver and transmitter will need similar field of view.  The 
earth stations can use a much narrower transmit FOV.


The Moon looks about the same size as a quarter ten feet away (a half of a 
degree).  From the Moon, the earth looks four times bigger (two degrees).  If a 
laser is on the Moon, it will be easier to detect when it is in shadow and the 
earthbound field of view does not include any of the Moon that is Sunlit.  , 
So receiver field of view should be less than

Lots of amateur astronomers view the Moon on a variety of telescopes.  A 
lasercomm system put up there should not interfere with their hobby, but should 
not require an exotic optical system at either end.

Would a laser pointer on the Moon apear brighter than a sunlight reflection 
from shinny object (say a flat sheet of aluminumized mylar 10 feet by 10 feet) 
to an observer on the Earth?  If not, then I am guessing that it would not 
interfere with most amateur Moon watchers any more than the Moon Base itself 
would.

The ideas are disjointed and incomplete.....are they interesting?


James
N5gui


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From laser@mailman.qth.net  Mon Dec 15 17:02:20 2003
From: laser@mailman.qth.net (Rochte, Robert)
Date: Mon, 15 Dec 2003 12:02:20 -0500
Subject: [Laser] RE: NLOS laser communication
Message-ID: <B5797316A5FED4119BBA0002A507D0375F20CE@GPA_PDC>

>I have looked into the geometry of rainbows (refraction from water
droplets) and Sun Dogs 
>(refraction from thin clouds of ice crystals) and even Sun pilars
(reflection from clouds of
>hexagonal crystal "disks" that tend to fall flat face down) for possible
use in NLOS 
>communication because they have angles where most of the light is
channeled, and thus should 
>have better range, if a very narrow field of view, and dependence on
specific weather 
>conditions.

Given the results that some amateurs (notably K3PGP) have obtained using
both visible-red and IR lasers, I assume that most non-line-of-sight (NLOS)
laser communication is the result of Mie scattering.  This could be from
aerosols or, as you suggest, from ice or water.

My particular interest is in flying a laser beacon experiment on one of my
high altitude balloons.  The laser beacon experiment (LBE) would be designed
to test NLOS using various take-off angles while at altitude and thereby
allow us to learn more about the nature of such scattering.

In the meantime (i.e., while I work on the design of the LBE), I am
interested in attempting NLOS laser communication with other amateurs in the
region (I'm in Detroit).  If you're interested, please let me know!  I'd
also invite anyone interested in helping with the LBE design and
construction to contact me.

73,
Robert
KC8UCH

--
Robert Rochte
Director of Information Technology
The Grosse Pointe Academy
171 Lake Shore Road
Grosse Pointe Farms, MI 48236
Tel. +1 313-886-1221 x155
FAX  +1 313-886-1418
www.gpacademy.org

From laser@mailman.qth.net  Mon Dec 15 21:30:37 2003
From: laser@mailman.qth.net (Tim Toast)
Date: Mon, 15 Dec 2003 13:30:37 -0800 (PST)
Subject: [Laser] moon repeater
In-Reply-To: <20031213090754.1FCB2328971@mailman.qth.net>
Message-ID: <20031215213037.63198.qmail@web13707.mail.yahoo.com>

i think it would be a worthwhile experiment to take
along a laser repeater with any future moon missions.
Not to mention being inexpensive in the case of the
passive repeater at least. There are many highly
reflective lightweight materials that could be used.

The reflectance of the moon's surface itself is very
low of course, maybe 5% or less? A plain white sheet
for a reflector is better than nothing but is
wastefull because it scatters the light in all
directions.

Better still, those screens that are used for motion
picture projection, which are semi-retroreflective
with a rather broad angle spread. Then next in line
possibly, some kind of retroreflective paint, like the
kind used on street signs and automobile tags. 
That type of material has some significant "gain" in
that it reflects most of the light back to the source,
yet not at so narrow an angle that it would only be
usefull for hearing ones own signals. Somewhere
between the movie screen and a corner cube in
reflectance angle spread. 

I think most kinds of retro-reflective paint have a
backscatter spread of about 5 to 10 degrees? That
might be great for covering the whole earth as seen
from the moon (2 degrees) without wasting an excessive
amount of the energy. 
Even though the moon keeps one side always toward the
earth, it liberates a bit during the month by a few
degrees (6 or 7). So an extra margin on top of that 2
degree "earth width" would take that into
consideration as well. Also with the added benefit of
being much less critical in alignment when being set
up, compared to say, a plane mirror type reflector. 

I was wondering if anyone has tried using the Apollo
retroreflectors with low power lasers in combination
with the 20 hz QRSS type modulation? Since that seems
to be the cutting edge of weak signal tech these days.
Even though it would only be usefull for hearing your
own signals i suppose.

Tim
toasty256@yahoo.com


````````````````````````````````````

Laser digest, Vol 1 #194 - 2 msgs

Message: 2
From: TWOSIG@aol.com
Date: Sat, 13 Dec 2003 00:38:19 EST
To: laser@mailman.qth.net
Subject: [Laser] moon repeater
Reply-To: laser@mailman.qth.net


This seems to be my night for wild ideas.  

I have heard a lot of news media chatter about the
President announcing a bold 
new venture for NASA on the 100th anniversary of the
Wright Brothers flight, 
next week.  What got my interest was returning to the
Moon with a permanently 
manned base.  

If such a base was built and maintained, the chance
for a system like ARISS 
could be added.  Then the system would be accessable
whenever the moon is above 
the horizon instead of a few minutes at a time.  And
gee, why not use a laser?  
Ok, how big?  How to arrange the effort?

To simplify the idea, I limited the concept to a
repeater.  There are passive 
and active repeaters.  The retro-reflectors left on
the Moon by the Apollo 
program are passive repeaters, but are too small and
too narrow.  A passive 
repeater would have to be large and allow a beam to
expand to a large area on the 
return to Earth.  How large would depend on the power
in the transmitted beam. 
 The expansion should be most of the earth to support
EME.  For an active 
repeater, the receiver and transmitter will need
similar field of view. The 
earth stations can use a much narrower transmit FOV.


The Moon looks about the same size as a quarter ten
feet away (a half of a degree).
>From the Moon, the earth looks four times bigger (two
degrees).  If a laser is on 
the Moon, it will be easier to detect when it is in
shadow and the earthbound field 
of view does not include any of the Moon that is
Sunlit. So receiver field of view 
should be less than 
Lots of amateur astronomers view the Moon on a variety
of telescopes.  A lasercomm 
system put up there should not interfere with their
hobby, but should not require 
an exotic optical system at either end.

Would a laser pointer on the Moon apear brighter than
a sunlight reflection from 
shinny object (say a flat sheet of aluminumized mylar
10 feet by 10 feet) to an 
observer on the Earth?  If not, then I am guessing
that it would not interfere 
with most amateur Moon watchers any more than the Moon
Base itself would.

The ideas are disjointed and incomplete.....are they
interesting?


James
N5gui


__________________________________
Do you Yahoo!?
New Yahoo! Photos - easier uploading and sharing.
http://photos.yahoo.com/

From laser@mailman.qth.net  Tue Dec 16 00:04:21 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Mon, 15 Dec 2003 19:04:21 EST
Subject: [Laser] moon repeater
Message-ID: <1cd.1607e522.2d0fa605@aol.com>

In a message dated 12/15/03 9:32:00 PM GMT Standard Time, toasty256@yahoo.com 
writes:

> I was wondering if anyone has tried using the Apollo
> retroreflectors with low power lasers in combination
> with the 20 hz QRSS type modulation? Since that seems
> to be the cutting edge of weak signal tech these days.
> Even though it would only be usefull for hearing your
> own signals i suppose.
> 
> 

This could be a very good idea. 
I have used slow CW to make many QSOs on the LF bands ( 73kHz and 136kHz) and 
it's a technique that works well.
I guess some further questions would be:
1) Over what distance on the earths surface would the reflected laser be 
visible?
I'm not at all sure of what happens to the divergence of a laser after it 
encounters a retroreflector?
2) although we can modulate audio onto the laser by chopping it with an 
accurate source what happens with doppler as the relative distance changes? I guess 
that the carrier changes wavelength but does the modulation? Possibly it does 
too, which would be a problem for very narrow bandwidth reception.

Probably still need a few Watts.

73

David   G0MRF


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From laser@mailman.qth.net  Tue Dec 16 01:09:42 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Mon, 15 Dec 2003 20:09:42 EST
Subject: [Laser] moon repeater
Message-ID: <1c5.1269d942.2d0fb556@aol.com>

I like the thinking that my weird ideas generated.  I don't know a whole lot, 
but I have two comments on the excerpt I copied below.   

On using the Apollo retro reflectors, please forgive me if my memory is 
faulty, but I think that a web site on the Lunar range experiment at the McDonald 
observatory in west Texas described the experiment.  In it, a high energy 
compressed laser pulse is sent through a one meter diameter telescope at the tar
get.  The light pulse expands from one meter to about two kilometers.  The 
retroreflector panel is about area of a disk a half meter in diameter, and reflects 
almost all of the incident light in a beam that returns to the earth with an 
expansion to an area of about 20 kilometers.  The photons of the beam are 
collected in a 1 meter telescope (I don't remember if it is the same one, or 
another.)  The point of this description was that they collected one photon from 
most of the pulses.  They then ran a statistical analysis on when the photons 
were received to use it it as a distance measuring device, which by now has an 
accuracy of about one or two inches.   Also as I remember there are three Apollo 
retro-reflectors and another one that I think is French made on a Russian 
probe.  They have been tracking not only the orbit of the Moon, but its "rocking" 
as well.   Cool stuff.

For a communication from the Moon to be received on the Earth, the beam will 
need to be more powerful when it leaves the Moon than the above system.  If 
you send a beam from Earth to the retroreflectors, you will need a much narrower 
beam or a lot more power.  If a lower power beam is sent to the Moon, it will 
need to be tightly columated to have a similar energy.  I guess that some 
astronomers (amateur or not) would know what kind of telescope would be needed.   
  On the down side, I think that any beam from the retroreflectors would come 
back to the Earth in a beam 20 kilometers around its origin.  EME for 
neighbors.

 That brings me to the other point about retroreflectors.  If a beam comes 
from the Earth, it does not matter how much the Moon rocks from side to side.  
The return beam will be back toward the line of origin with some additional 
expansion.  A retroreflector will need no more than two degrees of expansion.  
Practically, I think that one degree will be plenty.  The typical STOP sign is a 
lot more beam expansion.

Someone else suggested that the natural reflectivity of the moon is about 5%. 
 I think the number is more like 2 - 3 %.

As much as I like the I like the idea of a passive reflector, I am afraid 
that it will need to be too big for the first decade of a lunar base.  



James
N5GUI




I think most kinds of retro-reflective paint have a
backscatter spread of about 5 to 10 degrees? That
might be great for covering the whole earth as seen
from the moon (2 degrees) without wasting an excessive
amount of the energy. 
Even though the moon keeps one side always toward the
earth, it liberates a bit during the month by a few
degrees (6 or 7). So an extra margin on top of that 2
degree "earth width" would take that into
consideration as well. Also with the added benefit of
being much less critical in alignment when being set
up, compared to say, a plane mirror type reflector. 

I was wondering if anyone has tried using the Apollo
retroreflectors with low power lasers in combination
with the 20 hz QRSS type modulation? Since that seems
to be the cutting edge of weak signal tech these days.
Even though it would only be usefull for hearing your
own signals i suppose.

Tim
toasty256@yahoo.com

From laser@mailman.qth.net  Tue Dec 16 01:18:25 2003
From: laser@mailman.qth.net (J. Forster)
Date: Mon, 15 Dec 2003 20:18:25 -0500
Subject: [Laser] moon repeater
References: <1cd.1607e522.2d0fa605@aol.com>
Message-ID: <3FDE5D60.6F17784B@quik.com>

Someone needs to do a link calculation, IMO. From what I remember, the numbers just
didn't work for the amateur.

As I recall that the transmitter was a pulsed laser of several watts at least, the Tx
was a 24" or larger telescope, the Rx was similar and they only got a few photons back,
if they were lucky. The Rx was a range gated PMT.

This is not really practical for amateurs.

-John




From laser@mailman.qth.net  Tue Dec 16 01:22:36 2003
From: laser@mailman.qth.net (Andrew T. Flowers, K0SM)
Date: Mon, 15 Dec 2003 20:22:36 -0500
Subject: [Laser] moon repeater
References: <1cd.1607e522.2d0fa605@aol.com>
Message-ID: <3FDE5E5C.20207@alltel.net>

If I remember correctly from a conversation I had with PGP, he thought 
he might have detected his echo with about 500mw of IR and LF 
modulation, but we are talking about very long-term averaging.  Any kind 
of doppler effect should be insignificant--wavelength at 20Hz is around 
15000 km.  The biggest problem is likely the light from the moon.  Even 
a new moon is quite "bright" to a sensitive receiver.  Perhaps a very 
narrow filter for 780nm would be in order.  BTW, if anyone is going to 
try this, keep in mind that you'll have to pause every 2.5 seconds to 
listen for your echo--your own backscatter off the atmosphere will be 
MUCH stronger.  

I'm taking my LF tx/rx pairs back to Nebraska this week.  I might get a 
chance to play with some troposcatter stuff if the wx cooperates and I 
can convince N0RHL to man the other station  I'll have to figure out how 
to pack it in the suitcase.  I'll probably dissassemble quite a bit of 
the gear, especially the tunifish can assembly.  I imagine those would 
look pretty scary on the xray machine. :-)

Andy K0SM/2

G0MRF@aol.com wrote:

>In a message dated 12/15/03 9:32:00 PM GMT Standard Time, toasty256@yahoo.com 
>writes:
>
>>I was wondering if anyone has tried using the Apollo
>>retroreflectors with low power lasers in combination
>>with the 20 hz QRSS type modulation? Since that seems
>>to be the cutting edge of weak signal tech these days.
>>Even though it would only be usefull for hearing your
>>own signals i suppose.
>>
>>
>
>This could be a very good idea. 
>I have used slow CW to make many QSOs on the LF bands ( 73kHz and 136kHz) and 
>it's a technique that works well.
>I guess some further questions would be:
>1) Over what distance on the earths surface would the reflected laser be 
>visible?
>I'm not at all sure of what happens to the divergence of a laser after it 
>encounters a retroreflector?
>2) although we can modulate audio onto the laser by chopping it with an 
>accurate source what happens with doppler as the relative distance changes? I guess 
>that the carrier changes wavelength but does the modulation? Possibly it does 
>too, which would be a problem for very narrow bandwidth reception.
>
>Probably still need a few Watts.
>
>73
>
>David   G0MRF
>
>
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>to post in Plain-Text go to: http://www.expita.com/nomime.html  ---
>_______________________________________________
>Laser mailing list
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>http://mailman.qth.net/mailman/listinfo/laser
>




From laser@mailman.qth.net  Tue Dec 16 03:01:09 2003
From: laser@mailman.qth.net (Art)
Date: Mon, 15 Dec 2003 22:01:09 -0500
Subject: [Laser] moon repeater
In-Reply-To: <3FDE5E5C.20207@alltel.net>
References: <1cd.1607e522.2d0fa605@aol.com>
 <3FDE5E5C.20207@alltel.net>
Message-ID: <6.0.1.1.0.20031215215052.01cd3c28@mail.uninets.net>

>
>
>I'm taking my LF tx/rx pairs back to Nebraska this week.  I might get a 
>chance to play with some troposcatter stuff if the wx cooperates and I can 
>convince N0RHL to man the other station  I'll have to figure out how to 
>pack it in the suitcase.  I'll probably dissassemble quite a bit of the 
>gear, especially the tunifish can assembly.  I imagine those would look 
>pretty scary on the xray machine. :-)


Andy,

I think you meant you were flying back to zero land. If so, make sure your 
laser gear is taken apart and that it has the CDRH sticker on it. A 
reasonable facsimile will do as long as it is permanently attached (no 
string tags). If you don't disassemble the gear, you have to comply with 
more complicated regs because the laser is part of a complete assembly and 
the regs are much more stringent.

Remember, these airport people are paranoid and the average citizen things 
lasers will cut through flesh at 10 miles away!

Have fun in the dark skies of zero land!

Art 



From laser@mailman.qth.net  Tue Dec 16 10:41:12 2003
From: laser@mailman.qth.net (David D. Rea)
Date: Tue, 16 Dec 2003 05:41:12 -0500
Subject: [Laser] moon repeater
In-Reply-To: <6.0.1.1.0.20031215215052.01cd3c28@mail.uninets.net>
References: <1cd.1607e522.2d0fa605@aol.com> <3FDE5E5C.20207@alltel.net>
 <6.0.1.1.0.20031215215052.01cd3c28@mail.uninets.net>
Message-ID: <1071571272.16494.3.camel@liberty>

Don't recall if K3PGP hangs out on this reflector, but I'm almost
surprised we haven't seen a link to his laser "eyeball EME" page yet on
this thread...

http://66.51.112.117/k3pgp/Notebook/viseme.htm

Meanwhile, things are quiet at the K2THZ laser camp - been kept very
busy at work, which translates to a good thing for our company and a bad
thing for my terrahertz development! Here's hoping some free time opens
up soon...

73 de K2THZ

On Mon, 2003-12-15 at 22:01, Art wrote:
> >
> >
> >I'm taking my LF tx/rx pairs back to Nebraska this week.  I might get a 
> >chance to play with some troposcatter stuff if the wx cooperates and I can 
> >convince N0RHL to man the other station  I'll have to figure out how to 
> >pack it in the suitcase.  I'll probably dissassemble quite a bit of the 
> >gear, especially the tunifish can assembly.  I imagine those would look 
> >pretty scary on the xray machine. :-)
> 
> 
> Andy,
> 
> I think you meant you were flying back to zero land. If so, make sure your 
> laser gear is taken apart and that it has the CDRH sticker on it. A 
> reasonable facsimile will do as long as it is permanently attached (no 
> string tags). If you don't disassemble the gear, you have to comply with 
> more complicated regs because the laser is part of a complete assembly and 
> the regs are much more stringent.
> 
> Remember, these airport people are paranoid and the average citizen things 
> lasers will cut through flesh at 10 miles away!
> 
> Have fun in the dark skies of zero land!
> 
> Art 
> 
> 
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser


From laser@mailman.qth.net  Tue Dec 16 15:30:07 2003
From: laser@mailman.qth.net (Steve Bailey)
Date: Tue, 16 Dec 2003 10:30:07 -0500
Subject: [Laser] moon repeater
References: <1c5.1269d942.2d0fb556@aol.com>
Message-ID: <000b01c3c3e9$7d20be40$3e28b0cc@xxxxx>

I suppose one could lobby NASA to explode a large package of glass
micro-spheres [the kind used in highway centerline paint] over the lunar
surface.    -ka1rxx
----- Original Message -----
From: <TWOSIG@aol.com>
To: <laser@mailman.qth.net>
Sent: Monday, December 15, 2003 8:09 PM
Subject: Re: [Laser] moon repeater


> I like the thinking that my weird ideas generated.  I don't know a whole
lot,
> but I have two comments on the excerpt I copied below.
>
> On using the Apollo retro reflectors, please forgive me if my memory is
> faulty, but I think that a web site on the Lunar range experiment at the
McDonald
> observatory in west Texas described the experiment.  In it, a high energy
> compressed laser pulse is sent through a one meter diameter telescope at
the tar
> get.  The light pulse expands from one meter to about two kilometers.  The
> retroreflector panel is about area of a disk a half meter in diameter, and
reflects
> almost all of the incident light in a beam that returns to the earth with
an
> expansion to an area of about 20 kilometers.  The photons of the beam are
> collected in a 1 meter telescope (I don't remember if it is the same one,
or
> another.)  The point of this description was that they collected one
photon from
> most of the pulses.  They then ran a statistical analysis on when the
photons
> were received to use it it as a distance measuring device, which by now
has an
> accuracy of about one or two inches.   Also as I remember there are three
Apollo
> retro-reflectors and another one that I think is French made on a Russian
> probe.  They have been tracking not only the orbit of the Moon, but its
"rocking"
> as well.   Cool stuff.
>
> For a communication from the Moon to be received on the Earth, the beam
will
> need to be more powerful when it leaves the Moon than the above system.
If
> you send a beam from Earth to the retroreflectors, you will need a much
narrower
> beam or a lot more power.  If a lower power beam is sent to the Moon, it
will
> need to be tightly columated to have a similar energy.  I guess that some
> astronomers (amateur or not) would know what kind of telescope would be
needed.
>   On the down side, I think that any beam from the retroreflectors would
come
> back to the Earth in a beam 20 kilometers around its origin.  EME for
> neighbors.
>
>  That brings me to the other point about retroreflectors.  If a beam comes
> from the Earth, it does not matter how much the Moon rocks from side to
side.
> The return beam will be back toward the line of origin with some
additional
> expansion.  A retroreflector will need no more than two degrees of
expansion.
> Practically, I think that one degree will be plenty.  The typical STOP
sign is a
> lot more beam expansion.
>
> Someone else suggested that the natural reflectivity of the moon is about
5%.
>  I think the number is more like 2 - 3 %.
>
> As much as I like the I like the idea of a passive reflector, I am afraid
> that it will need to be too big for the first decade of a lunar base.
>
>
>
> James
> N5GUI
>
>
>
>
> I think most kinds of retro-reflective paint have a
> backscatter spread of about 5 to 10 degrees? That
> might be great for covering the whole earth as seen
> from the moon (2 degrees) without wasting an excessive
> amount of the energy.
> Even though the moon keeps one side always toward the
> earth, it liberates a bit during the month by a few
> degrees (6 or 7). So an extra margin on top of that 2
> degree "earth width" would take that into
> consideration as well. Also with the added benefit of
> being much less critical in alignment when being set
> up, compared to say, a plane mirror type reflector.
>
> I was wondering if anyone has tried using the Apollo
> retroreflectors with low power lasers in combination
> with the 20 hz QRSS type modulation? Since that seems
> to be the cutting edge of weak signal tech these days.
> Even though it would only be usefull for hearing your
> own signals i suppose.
>
> Tim
> toasty256@yahoo.com
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser


From laser@mailman.qth.net  Tue Dec 16 23:17:10 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Tue, 16 Dec 2003 18:17:10 EST
Subject: [Laser] moon repeater
Message-ID: <42.42f45f03.2d10ec76@aol.com>

Hmmmm.  This is an interesting idea.  I wonder how big a "spot" you can get 
per kilogram of spheres?

At full moon, it might be big enough to see in a small telescope.  There may 
be a natural equivalent -- there is a bright ring around most craters and rays 
that radiate from them which are noticeable on full moons.   

I also think that a flat mirror on the moon would work with more efficiency 
than retroreflectors.  The field of view of the earth is less than two degrees. 
 That is under 35 milliradians.  A small curve to expand the beam to 
.......say 10 milliradians........ might be as effective as, and a lot cheaper than 
retroreflector.   It would have to be aligned, but that might be done 
robitically, and as the Moon rocks on its axis, it may require re-adjustment.

On another subject, the story of the eyeball EME using a commercial laser 
display device to point at the moon and then being able to see a flash from the 
Apollo reflectors:   I believe in health skepticism.  Can anybody run an 
estimate on how many photons would have come back to the Earth from such a round 
trip.

I have heard that the human eye can detect a single photon, in a dark room.  
Bye for now.

James
N5GUI




>>>>>>
I suppose one could lobby NASA to explode a large package of glass
micro-spheres [the kind used in highway centerline paint] over the lunar
surface.    -ka1rxx

From laser@mailman.qth.net  Wed Dec 17 14:14:15 2003
From: laser@mailman.qth.net (WA4QAL)
Date: Wed, 17 Dec 2003 09:14:15 -0500
Subject: [Laser] moon repeater
References: <20031217090849.46EFC328B8B@mailman.qth.net>
Message-ID: <3FE064B7.8EBDACC4@ix.netcom.com>

Firstly, the environmentalists (and, probably the astronomers and 
planetary geologists) would throw a fit (possibly even justified).
Nextly, persuading NASA to do anything is almost impossible without
an excessive amount of paperwork and an incredible delay.  
Thirdly, I'm not real sure it would even work, since the glass
microspheres might settle into the lunar dust and be obscured.

Here's an alternate idea (just so I don't come across as 
throwing cold water over everthing).  What are the possibilities
of making either a hot air or Helium balloon out of the 
movie screen material (the kind covered with the 
micro-retro-reflectors) and sending it up?  Would there be
enough reflectance off of it to bounce laser signals off of
it?  Would this have to be done during the day, or could it be
floated at night?  I know the FAA has some rather stringent
rules on size and weight of balloons and their launch requirements,
but, since this would be just a balloon with no payload (other than
the envelope), it might qualify for a night launch.  Maybe.
Aiming might be a problem, but, then again, a simple sweep might 
be able to find it.  

Dave
WA4QAL

> Message: 2
> From: "Steve Bailey" <stevebailey@hypernet.com>
> To: <laser@mailman.qth.net>
> Subject: Re: [Laser] moon repeater
> Date: Tue, 16 Dec 2003 10:30:07 -0500
> Reply-To: laser@mailman.qth.net
> 
> I suppose one could lobby NASA to explode a large package of glass
> micro-spheres [the kind used in highway centerline paint] over the lunar
> surface.    -ka1rxx

From laser@mailman.qth.net  Wed Dec 17 14:28:20 2003
From: laser@mailman.qth.net (Rochte, Robert)
Date: Wed, 17 Dec 2003 09:28:20 -0500
Subject: [Laser] moon repeater
Message-ID: <B5797316A5FED4119BBA0002A507D0375F20E8@GPA_PDC>

You might want to look at the Peacestar project web site:
http://www.thepeacestar.org.  The ultimate goal is to launch an Echo style
balloon satellite -- no reason you couldn't bounce your lasers off it!

(The Grosse Pointe Academy, my school, is a sponsor of the project.)

73,
Robert
KC8UCH

>-----Original Message-----
>From: WA4QAL [mailto:wa4qal@ix.netcom.com]
>Sent: Wednesday, December 17, 2003 9:14 AM
>To: laser@mailman.qth.net
>Subject: Re: [Laser] moon repeater
>
>
>Firstly, the environmentalists (and, probably the astronomers and 
>planetary geologists) would throw a fit (possibly even justified).
>Nextly, persuading NASA to do anything is almost impossible without
>an excessive amount of paperwork and an incredible delay.  
>Thirdly, I'm not real sure it would even work, since the glass
>microspheres might settle into the lunar dust and be obscured.
>
>Here's an alternate idea (just so I don't come across as 
>throwing cold water over everthing).  What are the possibilities
>of making either a hot air or Helium balloon out of the 
>movie screen material (the kind covered with the 
>micro-retro-reflectors) and sending it up?  Would there be
>enough reflectance off of it to bounce laser signals off of
>it?  Would this have to be done during the day, or could it be
>floated at night?  I know the FAA has some rather stringent
>rules on size and weight of balloons and their launch requirements,
>but, since this would be just a balloon with no payload (other than
>the envelope), it might qualify for a night launch.  Maybe.
>Aiming might be a problem, but, then again, a simple sweep might 
>be able to find it.  
>
>Dave
>WA4QAL
>
>> Message: 2
>> From: "Steve Bailey" <stevebailey@hypernet.com>
>> To: <laser@mailman.qth.net>
>> Subject: Re: [Laser] moon repeater
>> Date: Tue, 16 Dec 2003 10:30:07 -0500
>> Reply-To: laser@mailman.qth.net
>> 
>> I suppose one could lobby NASA to explode a large package of glass
>> micro-spheres [the kind used in highway centerline paint] 
>over the lunar
>> surface.    -ka1rxx
>_______________________________________________
>Laser mailing list
>Laser@mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/laser
>

From laser@mailman.qth.net  Wed Dec 17 23:27:18 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Wed, 17 Dec 2003 18:27:18 EST
Subject: [Laser] moon repeater
Message-ID: <1a5.1d6ea99d.2d124056@aol.com>

Dave, WA4QAL makes some good points about the glass beads being covered by 
Moon dust if they were balistically scattered.   If you want to know how much it 
takes to get ideas past the "filters" at NASA, ask someone about SAREX and 
ARISS.  For that matter, ask them it was worth the effort.  

The Moon is nice to think about.  So are orbital ideas and baloons.   I still 
need to work on what I can get out of my equipment on the ground.  


Found out some interesting things about reflective signs, cloth, and 
microspheres.  The spheres act like spherical lenses (duh?).  If you put a mirror at 
the focal point of a lens, then a ray of light that passes through the lens 
will strike the mirror and be reflected.  If everything is aligned, the reflected 
ray will travel back out the lens and be refracted parallel with the 
incomming ray.  The mirror does not have to be particularly good for a bright spot to 
show, as in the case of a cat's eye shining in the dark.  A lot of reflective 
signs are made with a reflective layer covered by a spacing layer, then the 
spherical lenses, and usually covered with a protective transparent layer.

The focal length of a spherical lens depends on the index of refraction of 
the material.  It is possible to have a material that will focus much of the 
light striking a sphere on the surface of the opposite surface of the sphere.  If 
the light is reflected from that surface, it will come back out.  This would 
make a cloud of such spheres a very interesting reflector.  There might also 
be preferential reflections like water droplets that make rainbows. 

Would such spheres be better at reflecting light than crystals?  I am sure 
that there are crystal structures that have a retroreflective character, but 
would they have as good a reflective characteristic?

If we got a supply of retroreflective "dust" would it be worthwhile to 
release some from a balloon?  Would it be any advantage over a few yards of 
reflective cloth (perhaps used to make part of the parachute?) hung underneath?   (Or 
as suggested, the body of the baloon.)  For that matter could it be released 
from a satellite close to geosynchronous orbit?  (The dust would have to be 
tiny, or it might pose a hazzard to other satellites?)  If you let glass beads 
out near a radio satellite, it should not  affect radio waves.  Again, would the 
mass of a dust cloud be better used in a more conventional reflector.

James 
N5GUI





In a message dated 12/17/2003 8:16:45 AM Central Standard Time, 
wa4qal@ix.netcom.com writes:

Firstly, the environmentalists (and, probably the astronomers and 
planetary geologists) would throw a fit (possibly even justified).
Nextly, persuading NASA to do anything is almost impossible without
an excessive amount of paperwork and an incredible delay.  
Thirdly, I'm not real sure it would even work, since the glass
microspheres might settle into the lunar dust and be obscured.


Here's an alternate idea (just so I don't come across as 
throwing cold water over everthing).  What are the possibilities
of making either a hot air or Helium balloon out of the 
movie screen material (the kind covered with the 
micro-retro-reflectors) and sending it up?  Would there be
enough reflectance off of it to bounce laser signals off of
it?  Would this have to be done during the day, or could it be
floated at night?  I know the FAA has some rather stringent
rules on size and weight of balloons and their launch requirements,
but, since this would be just a balloon with no payload (other than
the envelope), it might qualify for a night launch.  Maybe.
Aiming might be a problem, but, then again, a simple sweep might 
be able to find it.  

Dave
WA4QAL

> Message: 2
> From: "Steve Bailey" <stevebailey@hypernet.com>
> To: <laser@mailman.qth.net>
> Subject: Re: [Laser] moon repeater
> Date: Tue, 16 Dec 2003 10:30:07 -0500
> Reply-To: laser@mailman.qth.net
> 
> I suppose one could lobby NASA to explode a large package of glass
> micro-spheres [the kind used in highway centerline paint] over the lunar
> surface.    -ka1rxx

From laser@mailman.qth.net  Fri Dec 19 00:51:22 2003
From: laser@mailman.qth.net (Jim Moss)
Date: Thu, 18 Dec 2003 16:51:22 -0800 (PST)
Subject: [Laser] moon repeater
In-Reply-To: <3FE064B7.8EBDACC4@ix.netcom.com>
Message-ID: <20031219005122.83337.qmail@web80403.mail.yahoo.com>

Perhaps some of you will recall...
1) many of the existing satellites contain retroreflectors. You can use them as targets and they are much closer (lower power required) but usually smaller.
http://ilrs.gsfc.nasa.gov/index.html
link budget:
http://www.wettzell.ifag.de/publ-cgi-bin/linkbudget.py
 
2) Japan launched a mirror covered satellite a while back. (another target with scattering potential) Sorry can't remember the bird...
 
Jim
N9JIM/6


WA4QAL <wa4qal@ix.netcom.com> wrote:
Firstly, the environmentalists (and, probably the astronomers and 
planetary geologists) would throw a fit (possibly even justified).
Nextly, persuading NASA to do anything is almost impossible without
an excessive amount of paperwork and an incredible delay. 
Thirdly, I'm not real sure it would even work, since the glass
microspheres might settle into the lunar dust and be obscured.

Here's an alternate idea (just so I don't come across as 
throwing cold water over everthing). What are the possibilities
of making either a hot air or Helium balloon out of the 
movie screen material (the kind covered with the 
micro-retro-reflectors) and sending it up? Would there be
enough reflectance off of it to bounce laser signals off of
it? Would this have to be done during the day, or could it be
floated at night? I know the FAA has some rather stringent
rules on size and weight of balloons and their launch requirements,
but, since this would be just a balloon with no payload (other than
the envelope), it might qualify for a night launch. Maybe.
Aiming might be a problem, but, then again, a simple sweep might 
be able to find it. 

Dave
WA4QAL

> Message: 2
> From: "Steve Bailey" 
> To: 
> Subject: Re: [Laser] moon repeater
> Date: Tue, 16 Dec 2003 10:30:07 -0500
> Reply-To: laser@mailman.qth.net
> 
> I suppose one could lobby NASA to explode a large package of glass
> micro-spheres [the kind used in highway centerline paint] over the lunar
> surface. -ka1rxx
_______________________________________________
Laser mailing list
Laser@mailman.qth.net
http://mailman.qth.net/mailman/listinfo/laser

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From laser@mailman.qth.net  Fri Dec 19 01:17:51 2003
From: laser@mailman.qth.net (Jim Moss)
Date: Thu, 18 Dec 2003 17:17:51 -0800 (PST)
Subject: [Laser] moon repeater
In-Reply-To: <20031219005122.83337.qmail@web80403.mail.yahoo.com>
Message-ID: <20031219011751.93915.qmail@web80403.mail.yahoo.com>

One mirrored satellite was STARSHINE.
Apparently a number of these have been launched.
http://science.msfc.nasa.gov/headlines/y2001/ast09oct_1.htm
http://www.azinet.com/starshine/ss4_manual_full.html
 
Apparently they have only about a 6 month life
http://www.space.com/businesstechnology/technology/starshine_orbit_000215.html
 
 
SEESAT-L (1998)
 
SUNSAT
http://www.jamsat.or.jp/oscar/sunsat/mirror/sspapers/s%26epayl1.htm
 
 
 
 

Jim Moss <n9jim-6@pacbell.net> wrote:
Perhaps some of you will recall...
1) many of the existing satellites contain retroreflectors. You can use them as targets and they are much closer (lower power required) but usually smaller.
http://ilrs.gsfc.nasa.gov/index.html
link budget:
http://www.wettzell.ifag.de/publ-cgi-bin/linkbudget.py

2) Japan launched a mirror covered satellite a while back. (another target with scattering potential) Sorry can't remember the bird...

Jim
N9JIM/6


WA4QAL wrote:
Firstly, the environmentalists (and, probably the astronomers and 
planetary geologists) would throw a fit (possibly even justified).
Nextly, persuading NASA to do anything is almost impossible without
an excessive amount of paperwork and an incredible delay. 
Thirdly, I'm not real sure it would even work, since the glass
microspheres might settle into the lunar dust and be obscured.

Here's an alternate idea (just so I don't come across as 
throwing cold water over everthing). What are the possibilities
of making either a hot air or Helium balloon out of the 
movie screen material (the kind covered with the 
micro-retro-reflectors) and sending it up? Would there be
enough reflectance off of it to bounce laser signals off of
it? Would this have to be done during the day, or could it be
floated at night? I know the FAA has some rather stringent
rules on size and weight of balloons and their launch requirements,
but, since this would be just a balloon with no payload (other than
the envelope), it might qualify for a night launch. Maybe.
Aiming might be a problem, but, then again, a simple sweep might 
be able to find it. 

Dave
WA4QAL

> Message: 2
> From: "Steve Bailey" 
> To: 
> Subject: Re: [Laser] moon repeater
> Date: Tue, 16 Dec 2003 10:30:07 -0500
> Reply-To: laser@mailman.qth.net
> 
> I suppose one could lobby NASA to explode a large package of glass
> micro-spheres [the kind used in highway centerline paint] over the lunar
> surface. -ka1rxx
_______________________________________________
Laser mailing list
Laser@mailman.qth.net
http://mailman.qth.net/mailman/listinfo/laser

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From laser@mailman.qth.net  Fri Dec 19 04:34:01 2003
From: laser@mailman.qth.net (Kevin Forbes)
Date: Fri, 19 Dec 2003 15:34:01 +1100
Subject: [Laser] Driver circuits?  ZD1954 10mW
Message-ID: <Law11-F60MOQTCTMHTb0005383e@hotmail.com>

Hi folks, I am requesting a bit of help regarding finding a suitable circuit 
to drive a laser diode that I have recently come across purchased and would 
like to experiment with. I purchased it from Jaycar Electronics in 
Australia, it s a 10 mW ZD1954,655nm TO18 supplied with a collimating lense. 
I did read somewhere that the supplied lense is not much chop, anyone 
support this? Should I or is it O.K. to make a driver circuit like the 
following, a variable voltage regulator at 2.3 volts in line with another 
voltage regulator wired up as a current limiter for 30-45 mA operating, 60 
mA MAX? Oh, and bye the way, I'd better ask how to utilise the built in 
photo diode properly while I'm at it.
Cheers folks and thanks in advance. Kevin Forbes, VK3UKF.

_________________________________________________________________
Hot chart ringtones and polyphonics. Go to  
http://ninemsn.com.au/mobilemania/default.asp


From laser@mailman.qth.net  Fri Dec 19 05:17:35 2003
From: laser@mailman.qth.net (David D. Rea)
Date: Fri, 19 Dec 2003 00:17:35 -0500
Subject: [Laser] Driver circuits?  ZD1954 10mW
In-Reply-To: <Law11-F60MOQTCTMHTb0005383e@hotmail.com>
References: <Law11-F60MOQTCTMHTb0005383e@hotmail.com>
Message-ID: <1071811055.14254.23.camel@liberty>

Hi Kevin - 

You can get as complicated as you want with laser driver circuits,
depending on the sensitivity of the diode, and in many cases how much it
costs. I've built complicated feedback-controlled instrumentation-grade
drivers for diodes that cost hundreds of dollars apiece, used in
holography. Our fellow laser board member Andy, K0SM, has had plenty of
success driving infrared diodes using constant current supplies; but his
diodes have a very wide operating current range.

Could you give us a bit more information about your diode... such as:

1) Do you have the datasheet, and if so what are the Iop and Ith values?
2) What is your intended use?
3) Do you need all 10mW, or would 7 or 8mW do?

73
Dave K2THZ

On Thu, 2003-12-18 at 23:34, Kevin Forbes wrote:
> Hi folks, I am requesting a bit of help regarding finding a suitable circuit 
> to drive a laser diode that I have recently come across purchased and would 
> like to experiment with. I purchased it from Jaycar Electronics in 
> Australia, it s a 10 mW ZD1954,655nm TO18 supplied with a collimating lense. 
> I did read somewhere that the supplied lense is not much chop, anyone 
> support this? Should I or is it O.K. to make a driver circuit like the 
> following, a variable voltage regulator at 2.3 volts in line with another 
> voltage regulator wired up as a current limiter for 30-45 mA operating, 60 
> mA MAX? Oh, and bye the way, I'd better ask how to utilise the built in 
> photo diode properly while I'm at it.
> Cheers folks and thanks in advance. Kevin Forbes, VK3UKF.
> 
> _________________________________________________________________
> Hot chart ringtones and polyphonics. Go to  
> http://ninemsn.com.au/mobilemania/default.asp
> 
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser


From laser@mailman.qth.net  Fri Dec 19 07:11:42 2003
From: laser@mailman.qth.net (Derek Weston)
Date: Fri, 19 Dec 2003 18:11:42 +1100
Subject: [Laser] Driver circuits?  ZD1954 10mW
In-Reply-To: <Law11-F60MOQTCTMHTb0005383e@hotmail.com>
References: <Law11-F60MOQTCTMHTb0005383e@hotmail.com>
Message-ID: <3FE2A4AE.90405@alphalink.com.au>

There's no laser hobbyist resource quite as useful as Sams:
http://www.repairfaq.org/sam/laserdps.htm#dpstoc

Kevin Forbes wrote:
> Hi folks, I am requesting a bit of help regarding finding a suitable 
> circuit to drive a laser diode that I have recently come across 
> purchased and would like to experiment with. I purchased it from Jaycar 
> Electronics in Australia, it s a 10 mW ZD1954,655nm TO18 supplied with a 
> collimating lense. I did read somewhere that the supplied lense is not 
> much chop, anyone support this? Should I or is it O.K. to make a driver 
> circuit like the following, a variable voltage regulator at 2.3 volts in 
> line with another voltage regulator wired up as a current limiter for 
> 30-45 mA operating, 60 mA MAX? Oh, and bye the way, I'd better ask how 
> to utilise the built in photo diode properly while I'm at it.
> Cheers folks and thanks in advance. Kevin Forbes, VK3UKF.
> 
> _________________________________________________________________
> Hot chart ringtones and polyphonics. Go to  
> http://ninemsn.com.au/mobilemania/default.asp
> 
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
> 
> .
> 


From laser@mailman.qth.net  Fri Dec 19 16:13:14 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Fri, 19 Dec 2003 11:13:14 -0500
Subject: [Laser] One test
Message-ID: <20031219.112010.116.3.riese-k3djc@juno.com>


Had a chance to test the Ramsey laser TX... this uses a 17/18 Khz sub
carrier
with audio modulation etc etc

Looks like the K3PGP front end will allow for copy of the audio. I dont
know
how sensitive this in but in day light it would work. Now this was short
distance
and with the laser spot on the side of mycar was able to decode OK

The output was fed into a simple audio amp 


IFY

I was able to see the Low Frequency output from this detector by running
the output into my LF converter.... Did this several years ago and dont
recall
the upper end.... Looking at the ramsey Kit I may pick one up 

I also suspect the PGP detector may feed the rcv OK by a simple
substitution
for the device provided  

Bob  K3DJC

From laser@mailman.qth.net  Wed Dec 24 22:30:34 2003
From: laser@mailman.qth.net (Pierre)
Date: Wed, 24 Dec 2003 17:30:34 -0500
Subject: [Laser] *****VHF DXCC VUCC WAS WAZ WAC date ? *****
Message-ID: <00fe01c3ca6d$8c2cd420$4b1ec818@moi>

Band #  Date        Grid   Call   Name  Worked Confirmed 
L#1                 DM33   KY7B   Bruce     5    5  -
L#2                 ?      WA7LYI ?         5    5  -
L#3     24 Aug 1995 DM13   W2ODH  Jim       5    5  ex-WB2ODH
L#4                 ?      WA6JOX ?         5    5  -
L#5                 DM44   WB7VVD Ward      5    5  -
L#6                 DM43   N7VUB  GREG      5    5  -
L#7                 ?      WB7WES ?         5    5  ex-KC7PCV
Hello, I'm looking for the date on VHF: DXCC VUCC WAS WAZ WAC certificate?
  day/month/year

Band #  Date        Grid   Call          Name    Worked Confirmed

list of VHF certificate
---------------------------------------------
http://pages.infinit.net/ve2pij/6mvucc.html
http://pages.infinit.net/ve2pij/2mvucc.html
http://pages.infinit.net/ve2pij/vhfdxcc.html
http://pages.infinit.net/ve2pij/vhfwas.html
http://pages.infinit.net/ve2pij/vhfwaz.html
http://pages.infinit.net/ve2pij/vhfwac.html

GRID:
CALL:
NAME:
BANDS:
STATE:
EMAIL:
ex-call:
tel.:
EME:
VUCC#+date:
VHFdxcc#+date:
VHFwas#+date:
VHFwaz#+date:
VHFwac  date:

A=50MHz, 7=70MHz Rcv, B=144MHz, C=222MHz, D=432MHz, 9=902MHz,
E=1296MHz, F=2304MHz, G=3456MHz, H=5760MHz, I=10GHz, J=24GHz,
K=47GHz, M=76GHz, N=119GHz, P=142GHz, R=241GHz, S=300GHz, L=Light
--
exemple 
VUCC
Band #  Date        Grid   Call          Name     Worked Confirmed 
A#972   12 Aug 1998 FN35   VE2PIJ        Pierre     300  300  -
G#65    14 Oct 2003 FN35qi VE2PIJ        Pierre       5    5  -

73 de Pierre VE2PIJ              FN35
http://pages.infinit.net/ve2pij
Grid square list + vhf contest calendar + all vhf-uhf contest info


From laser@mailman.qth.net  Sat Dec 27 00:07:53 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Fri, 26 Dec 2003 19:07:53 -0500
Subject: [Laser] TapTap
Message-ID: <20031226.190753.3736.0.riese-k3djc@juno.com>


Creak

Bob  K3DJC

From laser@mailman.qth.net  Sat Dec 27 05:56:33 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Fri, 26 Dec 2003 23:56:33 -0600
Subject: [Laser] cloudbounce
Message-ID: <20031227055633.OOKI15697.mta02-srv.alltel.net@mta02-srv>

I finally got out to do some tests with the PGP front end and my 11"x11" fresnel lenses.  It was overcast this evening, so I fired up my IR laser into the clouds (with expander).  I was able to get 40db S/N returns from my receiver 30 yds away pointing parallel to the transmitter. Next step is to see how far away I can receive this signal and maybe even do a xband QSO before I build another reciever for a 2x QSO.  I'll make some recordings and pictures when I get out next.

Andy K0SM

> 
> From: riese-k3djc@juno.com
> Date: 2003/12/26 Fri PM 06:07:53 CST
> To: laser@mailman.qth.net
> Subject: [Laser] TapTap
> 
> 
> 
> Creak
> 
> Bob  K3DJC
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
> 


From laser@mailman.qth.net  Sat Dec 27 07:26:09 2003
From: laser@mailman.qth.net (J. Forster)
Date: Sat, 27 Dec 2003 02:26:09 -0500
Subject: [Laser] cloudbounce
References: <20031227055633.OOKI15697.mta02-srv.alltel.net@mta02-srv>
Message-ID: <3FED3410.C66CA437@quik.com>

Are you sure it was cloudbounce, not backscatter?
-John

flowersa@alltel.net wrote:

> I finally got out to do some tests with the PGP front end and my 11"x11" fresnel lenses.  It was overcast this evening, so I fired up my IR laser into the clouds (with expander).  I was able to get 40db S/N returns from my receiver 30 yds away pointing parallel to the transmitter. Next step is to see how far away I can receive this signal and maybe even do a xband QSO before I build another reciever for a 2x QSO.  I'll make some recordings and pictures when I get out next.
>
> Andy K0SM




From laser@mailman.qth.net  Sun Dec 28 01:28:44 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Sat, 27 Dec 2003 20:28:44 -0500
Subject: [Laser] Just messing round
Message-ID: <20031227.202845.2368.1.riese-k3djc@juno.com>

I have the Ramsey TX finished and ran my K3PGP
detector into my LF rcv. As I thought it might
the 17 Khz signal, and its Modulation products are quite loud 
It will be interesting to see how much better the RX will be
in that it is filtered to get rid of the 60 cycle crap.

I have a C mount on the detector and the lens I am using isnt
terribly suited but the detc. output will pin the S meter when the
lens is centered on the reflected Laser light at a distance of 
several feet.

my only bitch is the method that Ramsey uses to mount the Pointer pen
and the method to operate the switch 

but whatever   HAR

Bob  K3DJC

From laser@mailman.qth.net  Sun Dec 28 03:57:11 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Sat, 27 Dec 2003 22:57:11 -0500
Subject: [Laser] And furthermore
Message-ID: <20031227.225711.3200.0.riese-k3djc@juno.com>

Just did a quick test and set the Laser up in the Living room and 
allowing 2 hops off the Hall wall into the shack

You cant see the light from the Laser in the shack

All the other lights are turned off but the PC screen was up

Using a Spectrum analyzing program ARGO I was able to see the 14 Khz 
signal from the Ramsey TX as a trace. The 14 Khz frequency appears to be 
stable enough to go to even slower analysis .I was using the 20 second
dot setting
on ARGO

this was with the PGP circuit feeding the LF converter and tuned to 14
Khz

NOW the bitch

This pen doesnt put out a proper signal and the dot is 3 to4 inches
across at 20 Ft
It looks like the diode may have some thing on it which is smearing the
signal
has anyone taken one of these apart or should I just yell at Ramsey for a
replacement

Lotsa fun anyhow

Bob  K3DJC

From laser@mailman.qth.net  Sun Dec 28 05:51:56 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Sat, 27 Dec 2003 23:51:56 -0600
Subject: [Laser] And furthermore
Message-ID: <20031228055156.GUC15697.mta02-srv.alltel.net@mta02-srv>

With the laser pens that I got in the kit, all you need to do is unscrew the "bullet" style cap (silver on mine).  Under that you will see an adjustable lens that is made for a large flat screwdriver.  Try screwing that in and out--it will adjust the distance between the lens and the diode to give you a tighter spot.  Make sure you don't use too small of a screwdriver lest you scratch the lens.

Andy K0SM

> 
> From: riese-k3djc@juno.com
> Date: 2003/12/27 Sat PM 09:57:11 CST
> To: laser@mailman.qth.net
> CC: wa3usg@comcast.net
> Subject: [Laser] And furthermore
> 
> 
> Just did a quick test and set the Laser up in the Living room and 
> allowing 2 hops off the Hall wall into the shack
> 
> You cant see the light from the Laser in the shack
> 
> All the other lights are turned off but the PC screen was up
> 
> Using a Spectrum analyzing program ARGO I was able to see the 14 Khz 
> signal from the Ramsey TX as a trace. The 14 Khz frequency appears to be 
> stable enough to go to even slower analysis .I was using the 20 second
> dot setting
> on ARGO
> 
> this was with the PGP circuit feeding the LF converter and tuned to 14
> Khz
> 
> NOW the bitch
> 
> This pen doesnt put out a proper signal and the dot is 3 to4 inches
> across at 20 Ft
> It looks like the diode may have some thing on it which is smearing the
> signal
> has anyone taken one of these apart or should I just yell at Ramsey for a
> replacement
> 
> Lotsa fun anyhow
> 
> Bob  K3DJC
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
> 


From laser@mailman.qth.net  Sun Dec 28 06:23:50 2003
From: laser@mailman.qth.net (John Matz)
Date: Sun, 28 Dec 2003 00:23:50 -0600
Subject: [Laser] And furthermore
References: <20031227.225711.3200.0.riese-k3djc@juno.com>
Message-ID: <001301c3cd0b$2a110a40$040110ac@dadsibm166>

 Hi
I don't know what style it is, but on a style that I have ....
1. Don't try to take the barrel apart.  The diode was on a little pcb which
fit into a slot on the lens assembly. The pcb switch was actuated by the
button on the side of the barrel.
2. The front light exit had a removable/interchangeable "image projector".
On one unit, the beam grazed the opening on one side until I removed it.
3. I found that when I removed that piece, the lens for the diode was
actually adjustable by screwing it in and out, closer and farther from the
diode.  It was hard to break loose, but once I knew it could move, it was
straightforward. The spot size became totally adjustable.
John Matz KB9II
----- Original Message -----
From: <riese-k3djc@juno.com>
To: <laser@mailman.qth.net>
Cc: <wa3usg@comcast.net>
Sent: Saturday, December 27, 2003 9:57 PM
Subject: [Laser] And furthermore


>
> Just did a quick test and set the Laser up in the Living room and
> allowing 2 hops off the Hall wall into the shack
>
> You cant see the light from the Laser in the shack
>
> All the other lights are turned off but the PC screen was up
>
> Using a Spectrum analyzing program ARGO I was able to see the 14 Khz
> signal from the Ramsey TX as a trace. The 14 Khz frequency appears to be
> stable enough to go to even slower analysis .I was using the 20 second
> dot setting
> on ARGO
>
> this was with the PGP circuit feeding the LF converter and tuned to 14
> Khz
>
> NOW the bitch
>
> This pen doesnt put out a proper signal and the dot is 3 to4 inches
> across at 20 Ft
> It looks like the diode may have some thing on it which is smearing the
> signal
> has anyone taken one of these apart or should I just yell at Ramsey for a
> replacement
>
> Lotsa fun anyhow
>
> Bob  K3DJC
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
>


From laser@mailman.qth.net  Sun Dec 28 11:48:07 2003
From: laser@mailman.qth.net (Tim Toast)
Date: Sun, 28 Dec 2003 03:48:07 -0800 (PST)
Subject: [Laser] almost ready
In-Reply-To: <20031227090722.58217328C33@mailman.qth.net>
Message-ID: <20031228114807.56630.qmail@web13706.mail.yahoo.com>

Next month i should be able to start doing some tests.
I've built the pgp front end (night version) and have
a short focal length (F:1) 16 inch plastic parabolic
mirror to use with it. I just need to make a mounting
for it. I have Argo and some other software.

I'll be using LED's and IR diode lasers from junk cd
players as transmitters/beacons. These cd player
diodes seem to have a nice 5 mw output or better just
judging from how they look through a b&w video camera.

I will probably post some images and stuff on my
website soon as i get results.
http://www.aladal.net/toast/

How far should the transmitter and receiver be from
each other to make sure your seeing a true cloud
bounce signal and not backscatter?



=====
Tim
toasty256@yahoo.com

__________________________________
Do you Yahoo!?
New Yahoo! Photos - easier uploading and sharing.
http://photos.yahoo.com/

From laser@mailman.qth.net  Sun Dec 28 19:15:15 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Sun, 28 Dec 2003 14:15:15 -0500
Subject: [Laser] And furthermore
Message-ID: <20031228.141848.2312.0.riese-k3djc@juno.com>

Thanks for the ideas on the adjustment
I was able to change the shape of the spot
but still isnt as sharp as I think it should be

I will drop Ramsey a note ,, see what they think

Bob K3DJC

From laser@mailman.qth.net  Mon Dec 29 23:13:44 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Mon, 29 Dec 2003 17:13:44 -0600
Subject: [Laser] laser and law
Message-ID: <20031229231344.FVZG11508.mta01-srv.alltel.net@mta01-srv>

I know this thread comes up from time to time, but I still haven't been able to get a straight answer.  Anyway, I'm just about ready to try some cloud-bounce QSOs.  What exactly are the rules for how much power I'm allowed to shoot into the sky--All of my stuff goes into a 3" beam expander, so the power density should be very low even with my 100mw IR diode.  Can anyone address this?  For now I'm just going to keep the beam away from aircraft, not that they would ever have a chance of being endanged by it in the first place.

Andy K0SM


From laser@mailman.qth.net  Mon Dec 29 23:26:17 2003
From: laser@mailman.qth.net (John McNulty)
Date: Tue, 30 Dec 2003 00:26:17 +0100
Subject: [Laser] laser and law
In-Reply-To: <20031229231344.FVZG11508.mta01-srv.alltel.net@mta01-srv>
Message-ID: <BC1676A9.C806%john@generalrobots.com>

"Set phasers to stun" ;-)

Sorry, couldn't resist...
73
J McN


On 30/12/03 0:13, "flowersa@alltel.net" <flowersa@alltel.net> wrote:

> I know this thread comes up from time to time, but I still haven't been able
> to get a straight answer.  Anyway, I'm just about ready to try some
> cloud-bounce QSOs.  What exactly are the rules for how much power I'm allowed
> to shoot into the sky--All of my stuff goes into a 3" beam expander, so the
> power density should be very low even with my 100mw IR diode.  Can anyone
> address this?  For now I'm just going to keep the beam away from aircraft, not
> that they would ever have a chance of being endanged by it in the first place.
> 
> Andy K0SM
> 
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
> 


From laser@mailman.qth.net  Tue Dec 30 01:58:54 2003
From: laser@mailman.qth.net (laser@mailman.qth.net)
Date: Mon, 29 Dec 2003 20:58:54 EST
Subject: [Laser] laser and law
Message-ID: <1d6.1768cb99.2d2235de@aol.com>

In a message dated 12/29/03 11:14:52 PM GMT Standard Time, 
flowersa@alltel.net writes:

> I know this thread comes up from time to time, but I still haven't been 
> able to get a straight answer.  Anyway, I'm just about ready to try some 
> cloud-bounce QSOs.  What exactly are the rules for how much power I'm allowed to 
> shoot into the sky--All of my stuff goes into a 3" beam expander, so the power 
> density should be very low even with my 100mw IR diode.  Can anyone address 
> this?  For now I'm just going to keep the beam away from aircraft, not that 
> they would ever have a chance of being endanged by it in the first place.
> 
> Andy K0SM
> 
> 

Hi Andy.

With the expanded beam you should be OK as the power density will be low and 
the IR cannot be seen.  I was worried by this until I discovered a high power 
green laser located a few miles south of here. It's used for bouncing off 
retroreflectors fitted to satellites. Apparently it generates element sets that 
are much more accurate than the usual NASA radar. We asked what precautions they 
took regarding aircraft......and they just looked blank!

73

David   G0MRF


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From laser@mailman.qth.net  Tue Dec 30 03:08:39 2003
From: laser@mailman.qth.net (B.E. Coyne)
Date: Mon, 29 Dec 2003 22:08:39 -0500
Subject: [Laser] laser and law
References: <1d6.1768cb99.2d2235de@aol.com>
Message-ID: <3FF0EC37.10C3@ix.netcom.com>

The link below gives airspace Notice to airman (NOTAM) and By zooming in
on the 
purple dots you will find info like I pasted below. There is other info
for the
curious also.




http://airspace.blm.gov/mapping/blm/index.cfm

3/3590 - GA.. LASER LIGHT RESEARCH ACTIVITY WILL BE CONDUCED AT AGNES
SCOTT COLLEGE, DECATUR, GEORGIA, 334555N/ 0841739W AND THE ATLANTA /ATL/
VORTAC 041 DEGREE RADIAL AT 11 NAUTICAL MILES. 0305120000 UTC UNTIL
0312310400 UTC AT AN ANGLE OF 90 DEGREES FROM THE SURFACE, PROJECTING UP
TO 14036 FEET. THIS BEAM IS INJURIOUS TO PILOTS''/AIRCREWS'' AND
PASSENGERS'' EYES IF VIEWED ON DIRECT AXIS. MACON /MCN/ AFSS, PHONE
478-752- 3475, IS THE FAA COORDINATION FACILITY. WIE UNTIL UFN 






G0MRF@aol.com wrote:
> 
> In a message dated 12/29/03 11:14:52 PM GMT Standard Time,
> flowersa@alltel.net writes:
> 
> > I know this thread comes up from time to time, but I still haven't been
> > able to get a straight answer.  Anyway, I'm just about ready to try some
> > cloud-bounce QSOs.  What exactly are the rules for how much power I'm allowed to
> > shoot into the sky--All of my stuff goes into a 3" beam expander, so the power
> > density should be very low even with my 100mw IR diode.  Can anyone address
> > this?  For now I'm just going to keep the beam away from aircraft, not that
> > they would ever have a chance of being endanged by it in the first place.
> >
> > Andy K0SM
> >
> >
> 
> Hi Andy.
> 
> With the expanded beam you should be OK as the power density will be low and
> the IR cannot be seen.  I was worried by this until I discovered a high power
> green laser located a few miles south of here. It's used for bouncing off
> retroreflectors fitted to satellites. Apparently it generates element sets that
> are much more accurate than the usual NASA radar. We asked what precautions they
> took regarding aircraft......and they just looked blank!
> 
> 73
> 
> David   G0MRF
>


From laser@mailman.qth.net  Tue Dec 30 16:29:02 2003
From: laser@mailman.qth.net (Jim Moss)
Date: Tue, 30 Dec 2003 08:29:02 -0800 (PST)
Subject: [Laser] laser and law
In-Reply-To: <1d6.1768cb99.2d2235de@aol.com>
Message-ID: <20031230162902.6565.qmail@web80407.mail.yahoo.com>

In the USA, the CLASS IIIa (<5mW) seems to be the maximum permitted power, regardless of density. (This is from everything that I have been able to determine.)
Indoor activities accessible to the public require a waiver above this amount.
I'd expect outdoor activities to be the same.
 
We've previously had a post on how to get a waiver....It included a link to a waiver form.
 
Jim
N9JIM/6


G0MRF@aol.com wrote:
In a message dated 12/29/03 11:14:52 PM GMT Standard Time, 
flowersa@alltel.net writes:

> I know this thread comes up from time to time, but I still haven't been 
> able to get a straight answer. Anyway, I'm just about ready to try some 
> cloud-bounce QSOs. What exactly are the rules for how much power I'm allowed to 
> shoot into the sky--All of my stuff goes into a 3" beam expander, so the power 
> density should be very low even with my 100mw IR diode. Can anyone address 
> this? For now I'm just going to keep the beam away from aircraft, not that 
> they would ever have a chance of being endanged by it in the first place.
> 
> Andy K0SM
> 
> 

Hi Andy.

With the expanded beam you should be OK as the power density will be low and 
the IR cannot be seen. I was worried by this until I discovered a high power 
green laser located a few miles south of here. It's used for bouncing off 
retroreflectors fitted to satellites. Apparently it generates element sets that 
are much more accurate than the usual NASA radar. We asked what precautions they 
took regarding aircraft......and they just looked blank!

73

David G0MRF


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_______________________________________________
Laser mailing list
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http://mailman.qth.net/mailman/listinfo/laser

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From laser@mailman.qth.net  Tue Dec 30 20:25:32 2003
From: laser@mailman.qth.net (Jean-Marie Capdeville)
Date: Tue, 30 Dec 2003 21:25:32 +0100
Subject: [Laser] laser and law
References: <20031230162902.6565.qmail@web80407.mail.yahoo.com>
Message-ID: <004e01c3cf13$143d5d40$0a0a0a0a@capgi5t4t47uo5>

Ther is some things writed about this subject in Sam's Laser faq.
There are also the sollowing links :
a.. CDRH - Center for Devices and Radiological Health (USA)
b.. CDRH Device Advice - On-Line Documents (USA)
c.. NRPB - National Radiological Protection Board (UK)
d.. RPB - Radiological Protection Bureau (Canada)
e.. Laser Institute of America (LIA) (Laser safety - ANSI Z136 standard)
f.. LIA - Laser Safety Information Bulletin
g.. LaserFX.com - Basic Laser Safety
h.. Naval Surface Warfare Center (Laser safety, info, links)
i.. Rockwell Laser Industries, Inc. Lasernet (Laser safety programs, laser
links)
j.. University of Pensylvania - Laser Safety Manual (Complete document)
k.. University of Waterloo - Laser Safety Manual (Complete document)
l.. USACHPPM - Laser and Optical Radiation Hazards Program
m..
n.. ----- Original Message -----
From: "Jim Moss" <n9jim-6@pacbell.net>
To: <laser@mailman.qth.net>
Sent: Tuesday, December 30, 2003 5:29 PM
Subject: Re: [Laser] laser and law


> In the USA, the CLASS IIIa (<5mW) seems to be the maximum permitted power,
regardless of density. (This is from everything that I have been able to
determine.)
> Indoor activities accessible to the public require a waiver above this
amount.
> I'd expect outdoor activities to be the same.
>
> We've previously had a post on how to get a waiver....It included a link
to a waiver form.
>
> Jim
> N9JIM/6
>
>
> G0MRF@aol.com wrote:
> In a message dated 12/29/03 11:14:52 PM GMT Standard Time,
> flowersa@alltel.net writes:
>
> > I know this thread comes up from time to time, but I still haven't been
> > able to get a straight answer. Anyway, I'm just about ready to try some
> > cloud-bounce QSOs. What exactly are the rules for how much power I'm
allowed to
> > shoot into the sky--All of my stuff goes into a 3" beam expander, so the
power
> > density should be very low even with my 100mw IR diode. Can anyone
address
> > this? For now I'm just going to keep the beam away from aircraft, not
that
> > they would ever have a chance of being endanged by it in the first
place.
> >
> > Andy K0SM
> >
> >
>
> Hi Andy.
>
> With the expanded beam you should be OK as the power density will be low
and
> the IR cannot be seen. I was worried by this until I discovered a high
power
> green laser located a few miles south of here. It's used for bouncing off
> retroreflectors fitted to satellites. Apparently it generates element sets
that
> are much more accurate than the usual NASA radar. We asked what
precautions they
> took regarding aircraft......and they just looked blank!
>
> 73
>
> David G0MRF
>
>
> --- StripMime Report -- processed MIME parts ---
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> or had an attachment. Attachments are not allowed. To learn how
> to post in Plain-Text go to: http://www.expita.com/nomime.html ---
> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
>
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> _______________________________________________
> Laser mailing list
> Laser@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/laser
>