On Wed, Jul 23, 2008 at 3:17 PM, Allen Vinegar tokens@myranch.com wrote:
There are several good howto tutorials to help people get started on the FM birds with a handheld. How about one for digital mode using a Kenwood TH-D7AG? Or is it not practical to attempt digital mode with a handheld? I am new to the satellites and have much to learn.
Thanks for any help you all can provide.
73, Al, W8KHP
Al, that's a good question. I have found the AMSAT digital satellites guide to be a very good read, though I don't think it provides exactly what you want.
In lieu of a guide like you describe, I would recommend that you use the FM guide to understand the tuning and reception issues and, at the same time, experiment with similar terrestrial digital modes.If you have a TH-D7AG, then start with APRS, since there is certain to be traffic on that mode in your area, and it's really easy to see when the ht is receiving data. Then combine the two skills to receive a bird that is running APRS.
A more advanced skill is to use the tnc inside the Kenwood to talk to a program on your laptop. Again, test that this is working terrestrially first. Use 1200 bps at first, and test it using local APRS signals and a terminal program on your computer. There are lots of cubesats, etc that run this mode many of these projects provide programs that decode their telemetry. When this is working, go up to 9600 baud and download from GO-32 and AO-51's telemetry.
If you can get your hands on a SSB radio, like a FT-817, give Delfi C3 a shot. Its software does soundcard demodulation of the telemetry *and* provides a graphical display of the meaning of the telemetry *and* uploads your frames to the folks in the Netherlands. Flat-out-cool, and it sounds like pretty soon we won't be able to play with this because the bird will become a communications satellite :-)
A severe warning, though: collecting digital information, especially telemetry, can be quite an addicting activity. After all, the other radio operator is on the ground, but the spacecraft's telemetry is all about the conditions in that hostile and fearsome territory, outer space.
73, Bruce VE9QRP