[Laser] transverter and transceiver schematics (EXCELLENT butnot first !!!)

[Les Rayburn]

It’s excellent work. I’d love to see someone make a printed circuit board of this design, and bundle it with the parts as a complete kit. I’m much more towards the “appliance operator” side of the scale than the “engineer” side of the scale. Kits are about my speed. 

I suspect that there are many hams who are interested in optical communications, perhaps even pushing the limits of propagation, but who are not interested in homebrewing their own gear. 

Anyone out there like to make some extra money by assembling a pair of these transverters for me!? 

73,

Les Rayburn, N1LF
EM63nf


From: laser 
Sent: Wednesday, November 17, 2010 7:10 PM
To: Free Space LASER Communications 
Subject: Re: [Laser] transverter and transceiver schematics (EXCELLENT butnot first !!!)

Congratulations on a nice circuit!!!

However, I suggest you rephrase the title, "World's first RF to Optical
Tranverter" as it is not accurate.  Over the years quite a few (on this
reflector as well as elsewhere) have built transverters specifically to
allow multimode HF and VHF transceivers to be used to modulate lasers mostly
using SSB and NBFM.

Although I haven't heard much out of them lately I know Dave, AA1A, and
John, K3PGP both were doing this many (~15?) years ago.  Dave was using a
10.0 to 10.5 Mhz IF (10 Mhz xtal) and John was using an 80 meter IF (3500
Khz xtal) tuning 3500 to 4000 Khz.  From what I remember they claimed the
performance was quite spectacular using the K3PGP front end and eliminated
the issues with AC hum from stray lighting.  They both claimed that although
the gain decreased at higher frequencies the sensitivity remained extrememly
good and cautioned people to not confuse gain with sensitivity.  I think
both were hanging out around 10 to 25 Khz when driving the laser.  I know
they tried the Radio Shack Jumbo LED.   High power LEDs like we have today
were not available.

About the same time period there was also someone on the west coast (Kerry?) 
that was using a two meter IF which consisted of a 2 meter hand held radio 
feeding a double balanced mixer with a 144 Mhz LO.  I know it performed well 
on NBFM but I'm not sure if it was ever used on SSB.

I did a search for AA1A and originally found his qsl.net url which linked to
a dead end (when I checked this afternoon) but after a bit more searching
was able to find Dave's transverter circuit and even a photo!

>From the AA1A website at http://www.radiocom.net/

"This baseband transverter used with the subcarrier laser equipment has
other uses. It makes an all mode transceiver covering 0-500 khz. out of a HF
amateur transceiver by using the transverter port. This will allow the
reception of whistlers, VLF, part 15, Fema, Boulder NIST 60 khz., European
broadcasting, aero beacons, Lowfer band, DGPS stations, the 500 khz. cw
marine band and even the new 136khz  band.

Schematic (dated 10/98 !!!) is here: http://www.radiocom.net/txvr.jpg

Photo is here: http://www.radiocom.net/txvrpix1.jpg

And so it seems, what is new is old and what is old is new.

=====

----- Original Message ----- 
From: "Tim Toast" <toasty256 at yahoo.com>
To: <laser at mailman.qth.net>
Sent: Tuesday, November 16, 2010 4:11 PM
Subject: [Laser] transverter and transceiver schematics


> hi all,
> I have posted Stuart's LED transceiver/transverter schematics on my
> site at: http://www.aladal.net/toast/detector.html
>
> -toast

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