15 Aug 2014

472kHz early evening

The move to 472kHz was made at about 1914z. Spots have been plentiful in both directions (received and given) but so far, no new reporters. I check results on WSPRnet. The first 30 minutes or so are show here.
472kHz WSPR spots - so far this evening
This evening, there are more stations active on 472kHz WSPR than I can ever recall (42). There were even more a little later.
UPDATE 2155z:  G3XIZ (46km) has just spotted me at -15dB S/N for spotter number 13 this summer.


Martin G7MRV said...

Monitoring again overnight, getting good spots already. Same set-up as last night - FRG-100 clipped to one half of main doublet.

Ive been testing my Wispy's receiver today Roger but have very poor sensitivity of only about -20dB, can you remember what your sensitivity figures were?

Im sure it will turn out to be a minor issue though

Roger G3XBM said...

Hope you copy me again this evening on 472kHz.

Try the 28MHz WISPY RX without the LPF and make sure the input tuned circuit on the mixer input peaks at 28MHz. Also, make sure the osc stage peaks at half frequency as needed for a Polyakov mixer. As I said, I have never built the full transceiver, just the separate circuits for TX and for RX. Both worked well. Can't see why it should not work as transceiver though.

Martin G7MRV said...

Havent copied you yet, but it was the early hours this morning, I expect much the same times.

Tx is fine, the oscillator is spot on. My suspicion is that its something to do with the change from your 3-pole Pi LPF to the 7-pole im using, or the fact ive gone from the trimmer at the diode switch to the toroid, mounted by the FET, via a short length of RG-174! I'll feed the test set direct to the RF amp tomorrow when I have time, bypassing the LPF and the switching diodes, see what happens then.

As you say, there should be no reason for it not to work as expected