Fljande info frn ANS:
If you have been following AO-40 telemetry on the Goddard server recently, you may have seen curious A-blocks with the message:
+——————————————————-+
~~ RECONSTRUCTED FROM DECODED FEC BLOCK ~~
+——————————————————-+
These blocks were decoded by Stacey Mills, W4SM, using a modification of the G3RUH MK II 400 BPS PSK demodulator, and a new version of the P3T telemetry decoding software program. The modification to the demodulator, developed by G3RUH, involves the addition of an 8 bit ADC, with minimal changes. For more details, see:
http://www.jrmiller.demon.co.uk/products/p3adc.html
With this modification, the MK II demodulator can continue to function in standard or hardware mode or, with the flip of a switch, can output ADC data at 9600 BPS, 1 byte per bit of telemetry data. P3T will also function in standard mode as before, but now includes the option for ADC input. In ADC input mode, P3T expects a serial port data stream as detailed above of one 8-bit byte per bit of telemetry data. In this mode, it will decode standard format telemetry blocks and will also handle all FEC decoding processes, generating a reconstituted A-block with the header as seen above. Eventually, P3T will be further modified to accept ADC data from a soundcard.
The performance of this system really has to be seen to be fully
appreciated. In FEC mode with even a modest receiving setup, every single block should be properly error corrected if the squint is less than 90 degs. FEC blocks that are barely audible or with severe spin-modulation fading will decode correctly. The P3T software is in final beta testing and will be available within a few days. This system will be demonstrated live at the upcoming AMSAT-UK meeting in Surrey by G3RUH using a solo RHCP patch antenna (no dish).
Klla: ANS 201