Pete, I certainly understand that the skimmers can overestimate S/N based
on applying a broadband noise model to what is really a nearby carrier. And
my gut feeling is that 40-67dB S/N's on a NA to EU path must be anomalous -
heck, most of the time I'm more than happy to be spotted by GW8IZR at 3dB
or 6dB S/N. At same time I was actually on the air making QSO's with EU and
the conditions were simply the best I've ever heard.
The way me, N3RR, and NO3M saw that enhancement to multiple EU skimmers in
the same hour makes me think that this was a real enhancement.
My belief that the enhancement was particularly strong to Belgium is not
just the ON5KQ skimmer report - I worked lots of ON's in that hour that I
had never heard on topband before. NO3M with his better antennas probably
worked many more that I didn't!
Tim N3QE
On Tue, Sep 22, 2015 at 9:37 AM, Pete Smith N4ZR <n4zr@contesting.com>
wrote:
> Thanks for the info, Tim. ON5KQ is one of our long-time RBN contributors,
> with something like the reference configuration (QS1R receiver, Skimmer
> Server 1.40.0.138, Aggregator 4.1). I wonder if maybe he has a very close
> station on 160M or AM broadcast whose signal drives his RX into clipping. I
> had to put in a high-pass filter here to control the effects of an AM
> station on 1550 KHz, but only during daytime, because at night it runs 6
> watts(!).
>
> The QS1R has no selectivity between the antenna and the ADC, other than a
> low-pass filter. Measurement of SNR takes place at the instant that CW
> Skimmer Server decides that it should spot a station, and normally
> anomalous SNRs only result if another station is near zero-beat. but with
> ADC clipping all bets are off.
>
> 73, Pete N4ZR
> Download the new N1MM Logger+ at
> <http://N1MM.hamdocs.com>. Check
> out the Reverse Beacon Network at
> <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
>
> On 9/17/2015 9:18 AM, Tim Shoppa wrote:
>
>> I felt conditions were really good to EU last night on 160M.
>>
>> But look at these S/N numbers below that came from reversebeacon. I know
>> that due to measurement to measurement jitter that we have to reject
>> outliers.
>>
>> There is a string of spots where me and other 3-landers are consistently
>> being spotted in EU with S/N in the 30-67 dB range.
>>
>> I my experience anything above 50dB S/N, pretty much means a bonecrushing
>> local. This sort of consistent spotting S/N over a whole hour, is just
>> amazing if it was true.
>>
>> The ON5KQ spots from 49dB to 67dB spots stand out as really strong, but at
>> same time, I worked so many small-gun ON's last night that I have never
>> heard on topband before, so maybe there was a supreme enhancement to
>> Belgium for most of that hour.
>>
>> Tim N3QE
>>
>> (Hope cut-and-paste job below survives E-mail)
>>
>> DX continent: NA - North America / DE continent: EU - Europe / band: 160m
>> cancel filter selection / search spot by callsign
>> de dx freq cq/dx snr speed time
>> EA5WU NO3M 1824.7 CW CQ [LoTW] 15 dB 24 wpm 0541z 17 Sep
>> EA5WU NO3M 1824.7 CW CQ [LoTW] 27 dB 24 wpm 0520z 17 Sep
>> EA5WU N3QE 1821.6 CW CQ [LoTW] 7 dB 23 wpm 0517z 17 Sep
>> EA5WU W4DJL 1814.5 CW CQ [LoTW] 15 dB 17 wpm 0516z 17 Sep
>> GW8IZR NO3M 1824.7 CW CQ [LoTW] 12 dB 26 wpm 0510z 17 Sep
>> EA5WU NO3M 1824.7 CW CQ [LoTW] 17 dB 26 wpm 0510z 17 Sep
>> ON5KQ NO3M 1824.7 CW CQ [LoTW] 54 dB 26 wpm 0508z 17 Sep
>> GW8IZR NO3M 1824.7 CW CQ [LoTW] 23 dB 26 wpm 0508z 17 Sep
>> EA5WU N3QE 1821.6 CW CQ [LoTW] 16 dB 23 wpm 0506z 17 Sep
>> DF4UE NO3M 1824.7 CW CQ [LoTW] 3 dB 25 wpm 0506z 17 Sep
>> ON5KQ N3QE 1821.6 CW CQ [LoTW] 49 dB 23 wpm 0504z 17 Sep
>> GW8IZR W4DJL 1814.5 CW CQ [LoTW] 40 dB 17 wpm 0503z 17 Sep
>> EA5WU W4DJL 1814.5 CW CQ [LoTW] 31 dB 17 wpm 0503z 17 Sep
>> EA5WU NO3M 1824.7 CW CQ [LoTW] 22 dB 28 wpm 0500z 17 Sep
>> GW8IZR N3QE 1821.6 CW CQ [LoTW] 12 dB 22 wpm 0459z 17 Sep
>> ON5KQ NO3M 1824.7 CW CQ [LoTW] 67 dB 28 wpm 0458z 17 Sep
>> GW8IZR NO3M 1824.7 CW CQ [LoTW] 35 dB 28 wpm 0458z 17 Sep
>> EA5WU N3QE 1821.6 CW CQ [LoTW] 18 dB 23 wpm 0457z 17 Sep
>> ON5KQ W4DJL 1814.5 CW CQ [LoTW] 16 dB 17 wpm 0456z 17 Sep
>> ON5KQ N3QE 1821.6 CW CQ [LoTW] 59 dB 22 wpm 0452z 17 Sep
>> DF4UE NO3M 1824.7 CW CQ [LoTW] 23 dB 28 wpm 0452z 17 Sep
>> ON5KQ N3QE 1821.6 CW CQ [LoTW] 61 dB 23 wpm 0450z 17 Sep
>> GW8IZR N3QE 1821.6 CW CQ [LoTW] 16 dB 23 wpm 0449z 17 Sep
>> EA5WU NO3M 1824.7 CW CQ [LoTW] 28 dB 31 wpm 0447z 17 Sep
>> GW8IZR NO3M 1824.7 CW CQ [LoTW] 34 dB 30 wpm 0447z 17 Sep
>> ON5KQ NO3M 1824.7 CW CQ [LoTW] 39 dB 30 wpm 0447z 17 Sep
>> EA5WU N3QE 1821.6 CW CQ [LoTW] 30 dB 23 wpm 0446z 17 Sep
>> DF4UE NO3M 1824.7 CW CQ [LoTW] 3 dB 24 wpm 0443z 17 Sep
>> GW8IZR NO3M 1824.7 CW CQ [LoTW] 14 dB 29 wpm 0440z 17 Sep
>> GW8IZR N3QE 1821.6 CW CQ [LoTW] 10 dB 22 wpm 0439z 17 Sep
>> ON5KQ NO3M 1824.7 CW CQ [LoTW] 10 dB 26 wpm 0437z 17 Sep
>> EA5WU N3QE 1821.6 CW CQ [LoTW] 6 dB 23 wpm 0435z 17 Sep
>> DF4UE N3RR 1820.5 CW CQ [LoTW] 32 dB 23 wpm 0435z 17 Sep
>> S50ARX N3QE 1821.6 CW CQ [LoTW] 18 dB 23 wpm 0433z 17 Sep
>> GW8IZR N3QE 1821.6 CW CQ [LoTW] 42 dB 22 wpm 0428z 17 Sep
>> EA5WU N3RR 1823.0 CW CQ [LoTW] 23 dB 22 wpm 0420z 17 Sep
>> ON5KQ N3RR 1823.0 CW CQ [LoTW] 20 dB 22 wpm 0420z 17 Sep
>> GW8IZR N3RR 1823.0 CW CQ [LoTW] 15 dB 22 wpm 0418z 17 Sep
>> GW8IZR N3QE 1821.6 CW CQ [LoTW] 42 dB 22 wpm 0417z 17 Sep
>> ON5KQ N3QE 1821.6 CW CQ [LoTW] 4 dB 23 wpm 0414z 17 Sep
>> GW8IZR N3QE 1821.6 CW CQ [LoTW] 7 dB 23 wpm 0408z 17 Sep
>> DF4UE N3QE 1821.6 CW CQ [LoTW] 5 dB 23 wpm 0406z 17 Sep
>> SV8RV NO3M 1824.7 CW CQ [LoTW] 6 dB 26 wpm 0404z 17 Sep
>> GW8IZR NO3M 1824.7 CW CQ [LoTW] 9 dB 26 wpm 0404z 17 Sep
>> S50ARX NO3M 1824.7 CW CQ [LoTW] 6 dB 27 wpm 0403z 17 Sep
>> DF4UE NO3M 1824.7 CW CQ [LoTW] 7 dB 25 wpm 0400z 17 Sep
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