Sometimes my software give some stations on WSPR quite decent reports as the signal decodes well. In these situations I am surprised not to be decoded myself as, even allowing for power difference, I should still be well above -30dB S/N. The reasons could be many:
- The other station is just on TX only
- The other station has a very high noise floor
- The other station has a deaf RX.
Apart from these, I cannot think why I should not be copied.
Hi Roger,
ReplyDeleteJust to let you know, the reason you get few spots from me is due to high noise level beaming in your direction at least (S4). I can normally get nice decodes of you when I beam east and the noise floor drops to a decent level, as does the aircraft scatter.
73 Colin - G6AVK
Other possible causes:
ReplyDelete- You are not putting out the power you think you are. I wonder if this might explain the non-reciprocity between us that we sometimes see.
- Aircraft Doppler might be hitting you worse than others owing to your proximity to flight paths from Stansted. Certainly this evening a lot of your 6m signals were quite badly disrupted.
Cheers, David G0LRD
I had it once before, when I put down the ALC | audio input, suddenly I got reports. 73 Paul
ReplyDeleteRoger's WSPR signals are very clean at my receiver so I don't think there is an ALC problem.
ReplyDeleteI thought of another possible reason for asymmetry: The frequency stability changing during receive and transmit. Most rigs are very stable during receive, but the short-term heat generation of transmit tends to cause drift on non-TCXO rigs. I think your rig Roger does this a little. Some, but certainly not all, of your transmissions show a slight slant and -1 drift reading.
Also being off frequency at either end can lose band edges. I think you are reporting CN8LI about 25Hz lower than he is putting him right on band edge according to you. I have him 25Hz in. I used to find the most drift on receive in the cycle after a transmission. FT897 with cooling fans good for 100 watts permanently on on Tx at 5 watts out!It caused me to miss a few on 28MHz, several on 50MHz and completely useless at 144MHz. I now have phaselock to an external OCXO. Also previously I could not complete a JT9 QSO on 28MHz
ReplyDeleteUsually I am giving other stations better reports than they give me. Appreciate I may be off in frequency a bit, but that is NOT the reason Bob. CN8LI is just above lower band edge with me currently.
ReplyDeleteG0LRD has just frequency calibrated one of my transmissions, so I should be able to offset a tad.