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Re: [CQ-Contest] KA9SWE skimmer frequencies - is it just me ?

To: Mike & Coreen Smith VE9AA <ve9aa@nbnet.nb.ca>
Subject: Re: [CQ-Contest] KA9SWE skimmer frequencies - is it just me ?
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Wed, 14 Aug 2013 06:33:09 -0400
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
Hi Mike - I noticed those spots over the weekend, but was too busy dealing with other issues here, and so haven't been in touch with him yet.

From the info we have, it appears that KA9SWE's running some sort of SDR that puts out stereo audio in I/Q format, probably a Softrock. If there is too great a disparity between the phase or amplitude of the two channels, the result is an I/Q image, which will appear at a frequency that is offset from the receiver's center frequency by the same amount as it is, but in the opposite direction. For example, if his center frequency was set at 14040, and you were really at 14020, then the image would appear at 14060.

KA9SWE has not been putting out "image spots" before this weekend (that I know of), so he should be able to fix his problem, whatever it is.

The new RBN filtering system, now in public beta test, is designed to let the user decide whether to ignore such spots until/unless it becomes apparent that the CQing station actually has QSYed.

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

On 8/13/2013 8:54 PM, Mike & Coreen Smith VE9AA wrote:
During this weekends WAE CW I saw that KA9SWE skimmer heard me lots.
(whether those spots go to a cluster, I have no idea)

What troubles me is that often it was on the wrong frequency.  I don't mean
a few hundred

Hertz, or even a kC but often, say I was on 14.048 it would report me on
14.114 or something crazy like that.

No other skimmers posted erroneous frequencies for me  (that I noticed) so I
think my signal is probably clean.

I was going to forget about it, but this has happened before on CW
contesting weekends and always with KA9SWE.

I don't have the foggiest clue where/how to search the history to even give
exact examples, but I saw it in real time on the weekend.



Mike, Coreen & Corey

Keswick Ridge, NB

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