30m QRSS beacon: QRV: Post-modification reports Print
Written by Hans Summers   
Monday, 25 May 2009 02:51

Post-Modification Reception Reports

After the modifications, 3 signal reports came in. None yet from PA and ON, the propagation hasn't been suitable for the much shorter distance than to Germany. The new frequency measurement was confirmed and appears to be a good choice. The "stictches" on some of the dashes seem to have dissappeared, due to the new power supply.

But... the staircase is now 30Hz high compared to about 20Hz before, and the lower half of it is less linear than it used to be. Furthermore, there is signficiant chirp on ths signal, a lowering of the frequency by a Hz or two during the first 1 or 2 seconds of each key-down.

From Peter DF3LP in Kiel, 31-Mar-04 18:00 UTC, showing the complete sequence. The chirp is easily visible. It appears much more noticeable on this screenshot than the others, because Peter has used a more expanded vertical axis and a more compressed horizontal (time) axis.

Next some beautifully clear shots from Peter DL6NL near Munich, 31-Mar-04 17:26 UTC. Here's the trademark staircase, the nice thing about this shot is that you can easily read the amount of frequency shift using the scale on the right hand side. You can see it's now about 30Hz high, and also notice the slight non-linearity towards the bottom of the stair. The two parallel horizontal lines just before the staircase are the signature of the callsign ID which is transmitted in 12wpm CW. This picture also shows G0UPL in the slow-hell section, almost visible despite Nyquist's prohibition!

On this second screen from Peter you can see a strange mark on the last dash in the "0" of the callsign. I'm not sure what this is, it doesn't appear on the other screenshots.

The final report was from Heinz Schnait OE5EEP, 31-Mar-04 19:44, from Austria JN67TW. It shows that the "stitching" problem of before has been solved, but also shows rather clearly the chirp.