[Skimmertalk] Image frequencies falsely reported using QS1R

K1TTT K1TTT at ARRL.NET
Thu Feb 14 18:03:04 EST 2013


Yes, I have.  I blame the cause of it on damage to the qs1r from lightning,
it was still working, but had some kind of internal sampling problem that
caused images like that.  They only seemed to happen on the 192khz sampling
rate, below that it seemed to operate normally.  When I first started
noticing it a cold restart of the qs1r seemed to fix it for a while, so that
may be something to try.  I could also force it to misbehave using the
sdrmax program by driving the sampling rate way up, then it would start
generating random junk on the waterfall display.  You might want to take a
look at it with the cwsl Tee and HDSDR, with that combination it splits the
data stream so you can use the HDSDR and skimmer at the same time, this is a
great help in finding noises and problems like images.

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


-----Original Message-----
From: Bob Wilson, N6TV [mailto:n6tv at arrl.net] 
Sent: Thursday, February 14, 2013 22:16
To: SkimmerTalk Reflector
Subject: [Skimmertalk] Image frequencies falsely reported using QS1R

Today my Skimmer Server 1.3 is reporting stations on both the "right"
frequency, and the *wrong* frequency, due to some type of signal image issue
that I haven't noticed before:

 N6TV <http://www.reversebeacon.net/qrz/rbn/N6TV>
RU0ZM<http://www.reversebeacon.net/qrz/rbn/RU0ZM>
28019.2 CW CQ15 dB 24 wpm 2157z 14 Feb
N6TV<http://www.reversebeacon.net/qrz/rbn/N6TV>
 RU0ZM <http://www.reversebeacon.net/qrz/rbn/RU0ZM> 28162.8 CW CQ11 dB 24
wpm 2157z 14 Feb


 N6TV <http://www.reversebeacon.net/qrz/rbn/N6TV>
P40L<http://www.reversebeacon.net/qrz/rbn/P40L>
28160.4 CW CQ [LoTW]20 dB 38 wpm 2155z 14 Feb





N6TV <http://www.reversebeacon.net/qrz/rbn/N6TV>
P40L<http://www.reversebeacon.net/qrz/rbn/P40L>
28021.6 CW CQ [LoTW]22 dB 37 wpm 2151z 14 Feb


This is using a QS1R attached to a Pixel RF-Pro1A 8' high, with a Norton
pre-amp; I don't think it's a signal overload issue.

The only thing that has changed recently is that I'm using Aggregator
version 2.4, though I don't think that has anything to do with it.  I
selected my normal "Contest Rotation" .ini file.  Maybe I need to limit the
CW range to frequencies below 28.150 in the that .ini file?  Or lower the
"LO" frequency?

Has anyone else seen and cured this problem when using a QS1R with Skimmer
Server set for 192 kHz bandwidth on 80 - 10m?

73,
Bob, N6TV
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