 |
FT8 anomaly or long delayed echo?
24 December 2017 | by My friend Alf, LA2NTA, has sent med these screenshots from when he has been operating FT8. The first image is when operating 10 meters and took place early in November.
 |
| Two of LA2NTA CQs being received by himself on 10 meter (in red) |
It shows how his own CQ comes back to him at 10.54.00 and at 11.00.00 and is decoded in his own receiver.
The second example is from 20 meters and took place just a few days ago.
 |
| LA2NTA CQ being received by himself on 20 meter (in red) |
For the first example he also took an image of the spectral display. It shows lots of repeated noise burst all over the FT8 band.
 |
| FT8 band on 10 meters showing some form of noise all over the band |
It is hard to explain this, but my hunch is that it is something local and not a propagation phenomenon, but who knows?
5 Responses to “FT8 anomaly or long delayed echo?”
Please support our generous sponsors who make AmateurRadio.com possible:
 Ham Radio Deluxe |
 Ham Radio Prep |
 Ham Radio School |
 KB3IFH QSL Cards  Hip Ham Shirts  HamRadioAuctions Reliance Antennas Enigma Shop |  morseDX  Ni4L Antennas  R&L Electronics antennas.us Ears to Our World |
- Matt W1MST, Managing Editor
Someone is pirating LA2NTA’s callsign.
The screenshots show the received signal with the same timestamp as when he was transmitting. As the timestamp is not included in the wspr message this is a local problem.
Around 1967 this was common at night on 20M. Both on ssb and Cw
I get that sometimes to and isn’t limited to just this mode, has to with buffering? My best guess is the some buffer isn’t empty when the receive cycle begins.
My wsjt program displays my own cq in the RX window when it reaches the tx limit. That is certainly a bug, and sound like it’s related to the op problem.