Tuesday, 27 January 2009

PSK with eeePC (from 3B8)


I have been asked in letter sent along with a recent qsl card to show any images of psk operating from 3B8 so here are a few images. I operated from 3B8CF shack and he uses an Alpha linear and an ICOM rig which we left in place and you can see them in the images. I operated an FT817 (PSK and CW) and FT897 (SSB). The images are small initially but if you click on them they should open full size. I used HRD psk31 (not DM780) and set up the software to operate a beacon as in this image.


You can see in the waterfall the band has some stations audible to me at this time. I was about the only 3B8 psk station present during the initial part of the trip, and always psk was qrp <5w.>

The key to operating psk pile ups was the ft817 I used was setup with 500Hz filters on ssb (operating 20m mostly for psk) and I would between the beacon sending scan the RX frequency (what ever you do don't touch either the software or the TX frequency). The FT817 would be operating split so the tx freq was locked but I could manually tune the RX. As I scanned I would note the callsigns and approximate freq up or down of the stations answering the small pileups. I was nearly always listening up from the TX freq, which I usually set to an odd frequency just above the start of the PSK freq window. Sometimes I would operate the 20m psk station in beacon mode for a while, if there was no response, or waiting for propogation to change whilst I was operating ssb on another frequency (I did this on 17m a couple of times). Then I would respond as I have just done in this case with RG3K.


As you can see sometimes the exchanges are very brief and subject to interference. Once spotted in the DX clusters (just added to the pain of others trying to contact me?) I didn't need to send the beacon and the qso were almost constant one after another. When you are the DX station it is interesting to note who calls you as propogation changes but it is so very important to maintain a regular pattern to your psk operating otherwise you will have huge amounts of qrm. I would advise make sure stations don't send you lots of information and ask in any cq for short qso like contests only. The other stations trying to contact you will appreciate it. In this case the RG3K station was in a contest already.
I made electronic logs of all the psk operating and double checked my qso logs afterwards.
psk from 3B8 was an enormously successful mode qrp.