[NLRS] FYI: Optical QSO

[Rob Jahnke]

It's great to see some interest in optical communications again.
Warren (WF0T) and I (Rob - K0XL) made a presentation about our Optical
experiments at Aurora 2019. Warren made the same presentation at CSVHFS in
July and at MUD in MUD in October of 2019..
The presentations are available at https://sites.google.com/view/k0xl .
Just scroll down past the more recent presentations.

One thing that might be of interest is the modulator which runs on an
Arduino ATTiny85. It features an iambic keyer function for CW as well as an
audio modulator for voice/music. It also has a beacon mode where the power
is stepped down in -3dB steps for signal strength measurements. The
schematic and code is available in the appendix section.

I think Warren has exceeded 10 miles (16km) for a QSO. The biggest
problem we have in MN/WI is finding long line of site paths. At the end of
the presentation, we outlined the possibility of testing a 50 km  (32mi)
path from Duluth to a Wisconsin Park along the south shore. We also had
some ideas about testing "Over the Horizon" paths considering the
refraction of light in the atmosphere.

Maybe there will be enough interest to resume some of this activity :-)

See you all at Aurora 2025 June 7th.
Rob - K0XL
 .


On Tue, Apr 15, 2025 at 12:10 AM Glen Overby <gpoverby at gmail.com> wrote:

> They're using a receiver design by VE2UG, which is based on the one by
> KA7OEI and K0XL.  Transmit is a PWM generator they bought on Amazon.
>
> I'm collecting parts for a system.
>
> 73,
> Glen
>
> On Mon, Apr 14, 2025 at 11:14 AM Jon Platt via NLRS <nlrs at mailman.qth.net>
> wrote:
>
>> Some of us through the years have played with optical contacts.  Here is
>> a link to W1VLFs YouTube video discussing and showing his 940 Nm 14 mile
>> QSO.  The QSB and seeing the half power reduction testing is interesting.
>> https://youtu.be/OXYJw9PyHd8
>>
>> 73, Jon
>> W0ZQ
>>
>>
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