Thursday, July 23, 2009

PropNet Spots are Now Being Received

OK, I now have a PropNet Spots being received by other stations. I think my transmitter was off frequency via the tones from the sound card. I am somewhat at the mercy of the 6 digit display of the ICOM-730 and it frequency drift.

Normally I can set the received base frequency right on the money (via my band edge marker) but things drift over time on the ICOM.

It is kind of fun watching WSPR and PropNet programs compete for the transmitter, actually they share as their sound card tones are different. Due to the two programs slightly random transmitting schedule, they sometime are actually send tones at the same time. The transmitter just turns the two tones into two different FSK RF signals.

I use VOX on the transceiver and all works well with the sound card and the two programs. Except if the computer needs to "beep" (as on an error) - the transmitter is triggered. I try to turn off the VOX if I know I am doing something on the computer that will generate a lot of beeps. It would be best to use PTT via the serial DTR line as documented on the web, but I have not built that connection yet.

In this capture, you can see the WSPR program output started first at (10.)140225mHz, and then the PropNet program started at a higher tone (RF Frequency (10.)140425mHz) .

WSPR signal transmits for 2 minutes, while PropNet transmits for about 20 seconds. Click on the image to see a larger view.

Note: the display program "Spectran" does not support 8 digit frequency calibration scale, so add 10mHz to what you see.

Also note, this image capture was created on another local computer and a standalone local Kenwood R-2000 Receiver - which was somewhat overloaded by the transmissions.

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