[amsat-bb] Re: Video: micro-controller doppler tuning

Bruce Robertson ve9qrp at gmail.com
Fri Feb 5 04:32:15 PST 2010

On Fri, Feb 5, 2010 at 8:01 AM, Mark L. Hammond <marklhammond at gmail.com> wrote:
> Very nice, Bruce!  What a great project.
> In the video you mention something about CW--is that an ID for the bird currently being tracked, or what?  I might have missed it...

Correct. The tracker announces the bird in CW as it rises and sets,
and it periodically announces its azimuth and elevation, like 'HO68
WSW H[igh]'. The final product is potentially so very small that I
didn't want a display screen to increase its size unreasonably.

What it *doesn't* do is provide any prediction. I figure you can print out
a chart of these things, or just take pot luck as the tracker scans
through the 10 or so birds for which its EEPROM provides space.

You can hear the CW announcement during the QSO at the beginning of
that video, but a clearer indication is 47s through this video:

What the spectran view in the video shows is how the tracker stops
tuning the radio while it is announcing in CW, causing doppler shift
briefly to take over. I need to rewrite my CW library so that it calls
the tuning function during the elements that are long enough to allow
it, such as spaces between words.



> At 01:23 AM 2/5/2010 -0400, Bruce Robertson wrote:
>>The following video shows the current state of my
>>doppler-tuning-on-a-chip project. It shows the project's first QSOs
>>and  its stability while tracking a LEO beacon.
>>73, Bruce
>>Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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> Mark L. Hammond  [N8MH]

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