Topband: Crazy high RBN SNR reports

[VE6WZ_Steve]

I have been operating my RBN skimmer for 8 years. It is common for me to get emails asking about unusually high SNR reports, especially from trans-continental CQs.

I thought it would be good to post some information here on the reflector about how this happens.

I am referring to those 50-90 dB SNR reports that we get, but sometimes even the 20-30 dB reports when 2-5 dB is more likely.

Here are some of the reasons how this happens at my RBN:

1.) My SDR skimmer is decoding RA4LW at 3 dB.  CW skimmer has decoded the RA4LW CQ, but a LOCAL NA calls RA4LW, and the local caller gets his very high SNR value included with the RA4LW spot.  RA4LW gets spotted at 50 dB. This is especially likely when the local NA station uses RA4LW’s call in the exchange.
This is not uncommon. I can be calling CQ on 160m, and get RBN reports from OH6BG at 50 dB, even though I am usually only 3-5 dB.  This is probably because some “local EU” like OH1XX is calling me, and his very high SNR gets mixed in with my CQ at the OH6BG skimmer.

2.) As above, but it is ME calling RA4LW, and even though my SDR skimmer radio is muted during TX, it is still very overloaded and the high overload signal gets included in the SNR value.  RA4LW gets spotted at 95 dB.  (Note; My RBN SDR skimmer radio is always on, even when I am transmitting).

3.) My skimmer is decoding RA4LW and gets the CQ at 3 dB, but I am currently calling CQ and overloading my skimmer SDR even though I am off frequency, and that very strong overload signal gets included in the SNR calculation.  RA4LW gets spotted at 95 dB.

4.) Someone local is calling CQ, but for some reason includes a DX call.  A combination of CQ and the call is requires for a spot.

Continued fantastic topband DX at VE6WZ.  Last night I logged 52 EU in 2 hours. Over the last week I have been working 30-50 EU each night. Many new “never worked before on 160” calls.  Over 520 EU CW QSOs  here at VE6WZ in the last 3 months.
All on CW.  160m is alive with CW ops!

73, es lets continue to enjoy the great 160m DX this season.

de steve ve6wz