[Skimmertalk] extremely high SN readouts

[Andy KU7T]

Just FYI, 

I also get occasional high S/N numbers for stations I have just worked at
the same station. I do not have the QS1R locked out in any way except with
the front end protection from the wiki. The numbers for me are as high as 70
- 90 db (never higher than 90, but possibly this may be band dependent, and
I never operate on bands lower than 40m).  Overall, it does not happen very
often, so I have not bothered.  Antennas are about 250 feet apart.

Also, I have submitted a feature request to Alex for an improvement of the
skimmer software to exclude spots that are higher than a configurable S/N
value. I would set this to 65 db and that would just ignore these spots.
Hope that this will get added at some point.

Andy
KU7T


-----Original Message-----
From: Skimmertalk [mailto:skimmertalk-bounces at contesting.com] On Behalf Of
David Robbins
Sent: Sunday, October 23, 2016 12:30 PM
To: 'Larry - K1UO' <k1uo at tds.net>; 'Skimmertalk'
<skimmertalk at contesting.com>
Subject: Re: [Skimmertalk] extremely high SN readouts

The bogus snr doesn't bother me.  may cause some confusion if anyone tries
using your skimmer to compare snr with other stations, but that should be
minor.   Full duplex may be interesting, or just turn power all the way down
and key on ssb, that would eliminate any rf possible problems... it may be a
question for ve3nea to see if the noise level is averaged over a long time
period so if a signal is there right after the receiver is unmuted would
that give the odd snr values.

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373



-----Original Message-----
From: Larry - K1UO [mailto:k1uo at tds.net]
Sent: Sunday, October 23, 2016 19:18
To: k1ttt at arrl.net; Skimmertalk
Subject: Re: [Skimmertalk] extremely high SN readouts

Yes,  Skimmer is receiving the complete selected IQ bandwidth (24,48,96 or
192) from the 6700 via the Flex DAX (Digital Audio System) IQ transport.
RX is muted during TX normally but I could try using the Full Duplex feature
of the Flex to test your theory Dave.
If the occasional spots with bogus SN ratios are bothersome to the RBN
please let me know and I will take down the Skimmer.
Thanks for the hints.

-----Original Message-----
From: David Robbins
Sent: Sunday, October 23, 2016 12:54 PM
To: 'Larry - K1UO' ; 'Skimmertalk'
Subject: RE: [Skimmertalk] extremely high SN readouts

Is the skimmer receiving from the flex6700??  If so, what does it receive
when you tx??  If it is muted maybe the noise detector in the skimmer is
hearing dead quiet and it takes it some time to get a new real noise
sample??

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373



-----Original Message-----
From: Skimmertalk [mailto:skimmertalk-bounces at contesting.com] On Behalf Of
Larry - K1UO
Sent: Sunday, October 23, 2016 16:24
To: Skimmertalk
Subject: Re: [Skimmertalk] extremely high SN readouts

I thought of Skimmer software overload but the skimmer software and PC is
here at the HOA and the Flex6700 and TX antenna is at my remote 8 muiles
away.   I am using a Flex Maestro connected to the remote via VPN.
I usually only send RBN spots for 80 or 160 when I am on but I cant pinpoint
why the occasional extreme SN ratios reported.

Larry  K1UO

-----Original Message-----
From: David Robbins
Sent: Sunday, October 23, 2016 11:00 AM
To: 'Skimmertalk'
Subject: Re: [Skimmertalk] extremely high SN readouts

I would guess that the tx overloads the skimmer software itself and drives
the calculated noise floor way down.

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373



-----Original Message-----
From: Skimmertalk [mailto:skimmertalk-bounces at contesting.com] On Behalf Of
Larry - K1UO
Sent: Saturday, October 22, 2016 22:59
To: Skimmertalk
Subject: [Skimmertalk] extremely high SN readouts

Running SSDR 1.9.13, CW Skimmer 1.9, Aggregator 4.1 and SDR Bridge 1.5.

I am running this with a Flex6700 and I am trying to figure out what is
causing the SN ratios on the reported skimmed cw spots to be reading so
high.  The skimmer/bridge combo seems all ok up to the point I transmit on
the 6700 and after that for a period of time the SN reports are over the
100db range!    One a minute ago was 146db on a EU station in the Stew Perry
on 160 that should have read around the 20-25db range as I was listening to
it.  Any ideas?

Larry  K1UO
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