[Skimmertalk] Image frequencies falsely reported using QS1R

[Pete Smith N4ZR]

It is probably worth looking for clipping resulting from strong MW or SW 
broadcast stations, because the QS1R has essentially no selectivity in 
front of the ADC.  The latest versions of SDRMAX include code to make 
the clip light stay on even if clipping is only occurring very briefly, 
so it might be worth running yourQS1R under that software to see what 
you see.  I wound up putting a Clifton Labs elliptical high-pass filter 
in front of my receiver, to get rid of an AM broadcast station on 1550 KHz.

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 2/15/2013 10:03 AM, Timothy Coker wrote:
> I am running 192khz with a Clifton Labs pre-amp like N6TV and yourself Rich.
>
> I wonder if I was online transmitting during a contest during those times
> you saw it? I often will let the QS1R run with pre-amp using a dipole
> oriented 90 degrees offset (but only 6' vertically spaced) from my TX
> antennas using LP or HP without grounding the input of the QS1R.
>
> Always up for anyone letting me know if they see any spot issues so I can
> improve the setup.
>
> 73,
>
> Tim / N6WIN.
> http://www.n6win.com
>
> On Thu, Feb 14, 2013 at 3:10 PM, Rich Hallman - N7TR <rich at n7tr.com> wrote:
>
>> I have seen this before.....using 192 kHz sample rate with a preamp.
>> Would be interested if others are seeing this.    I've noticed the N6WIN
>> skimmer spot me on wrong frequencies in the past and was worried I had
>> harmonics...but it was never on a harmonic from where I was operating.
>>
>> 73. Rich. N7TR
>>
>> On Feb 14, 2013, at 2:17 PM, "Bob Wilson, N6TV" <n6tv at arrl.net> wrote:
>>
>>> 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
>>> _______________________________________________
>>> Skimmertalk mailing list
>>> Skimmertalk at contesting.com
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