[Laser] Laser Communications in the Sacramento, Ca. area.

[n9jim]

Kerry,
I'd be glad to put it up at my site...
http://www.qth.net/wb9ajz/laser/laser.html
Jim
N9JIM/6
San Jose (where we have 4 known laser ops)

Kerry Banke wrote:

> Chuck, WB6IGP and I built up a couple of Laser pointer communicators a few
> years back & Chuck published a three part article in 73 Magazine on those
> units.  If someone is willing to put a number of pictures up on a web site
> somewhere, I can provide the article as well as a number of photos of the
> parts & pieces.   Basically the transmitter unit uses the VCO from a 4046
> type PLL chip to provide a 35 KHz square wave which is modulated by audio
> from an electret microphone and  op-amp for about 5 KHz deviation.  The VCO
> drives a FET which supplies a 4 volt square wave to the laser pointer.  The
> laser pointer may be used with or with out additional optics (beam
> expander).   The receiver consists of a Fresnel reading lens cut &  mounted
> inside a 4" PVC pipe housing with a PIN photo detector  at the focal point.
>  The diode feeds a high gain  35 KHz preamp which was salvaged from an old
> TV remote control and modified for a linear output.  The amplified receive
> signal is then mixed with a 144 MHz oscillator to upconvert to 144.035 MHz
> so we can use a basic 2 meter FM handytalki for the final receiver.  For
> data and SSTV we connect the sound input & output from a laptop computer to
> the receiver and mic audio on the optical communicator and use share ware
> programs available off the web.   Probably the most critical item for
> success is building a stable and accurate pointing setup.  We use 24X rifle
> scopes (4X will do) and have added  fine micrometer adjustments which move
> the laser & scope together.   It's very important to check out the
> alignment of the laser, scope and receiver each time the unit is setup to
> avoid wasted time and frustration when  making the contact.  With this type
> of approach, the main time spent  in establishing contact is initially
> locating each other visually on the hill tops using high power  spot
> lights.  After that it's a piece of cake. 
> 
>  - Kerry N6IZW -
>  
> 
> At 11:05 AM 5/13/02 -0400, you wrote:
> 
>>Please share with the group your interface and modulation
>>techniques..........
>>
>>mcsdottom
>>
>>60 miles NE of Detroit..
>>
>>Macintosh for productivity;
>>Linux for reliability;
>>Palm OS for portability;
>>Windows for solitaire.
>>
>>
>>
> 
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