[hpsdr] A chirp and a Whisper - very long post Part 3 of 3

[Phil Harman]

.Continuation from part II



The free sound card software Spectrum Lab:



< http://www.qsl.net/dl4yhf/spectra1.html >



will both generate and demodulate chirp signals.



What would be interesting would be to have a single board that generates a

chirp modulated carrier and could be used as the replacement for the low

level drive stage in a conventional  6m beacon.  You guessed it - Penelope!



Bill kindly offered to take on this 'Weekender Project'  (which did actually

fit in a weekend for once!) and produced a version of his PennyWSPR code

that included BOTH a chirp and WSPR beacon and would trigger on the 1 PPS

from a GPS receiver.   The nominal frequency of the beacons is at 50.3MHz

(for initial testing) with the chirp extending  from 300Hz to 1300Hz above

this and the WSPR beacon  1500Hz above.  The WSPR beacon is 6dB below the

power level of the chirp beacon.



Since VHF beacons in VK are allocated on a 2kHz channel spacing the spectrum 
of the two signals fits nicely within an allocated channel.



Work is also in progress to look at including an aural CW ident on the 
allocated carrier frequency.



Testing is about to start and I'll report progress in due course.



If testing is successful then we intend to develop an FPGA based PCB that 
will provide a 6m/2m beacon exciter stage. The board is intended to be used 
as a replacement for the low level driver board in an existing beacon. As 
well as the FGPA, power supplies etc, it will include a GPS receiver and 
oven controlled 10MHz reference.



TAPR have already expressed an interest in manufacturing the board.



73's Phil....VK6APH



P.S. Sorry, I not able to provide copies of the Dubus article.








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