[Skimmertalk] skimmer image rejection

Pete Smith n4zr at contesting.com
Sun Dec 5 13:49:47 PST 2010


This is an indication that the balance between the I and Q channels is 
off, either in gain or phase.  Skimmer has the ability to automatically 
compensate for this, but it requires that you turn it on and then either 
find or supply strong signals across the entire passband.  Check the 
Help file for more info.

Really bad imbalance can lead to images that are essentially the same 
level as the fundamental; with good compensation 60-80 dB of 
cancellation seems pretty easy to achieve

73, Pete N4ZR

The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000


On 12/5/2010 1:51 PM, Mark N2QT wrote:
> During the ARRL 160 test a couple of local guys were on and skimmer was
> reporting them
> on the image frequencies.  They were at SN levels on the fundamental of
> 60-80 DB. Is this
> typical?
>
> Running an EMU-0202/LP-PAn and a Softrock / Quartet.  They seem pretty
> similar but didn't
> really check too carefully.
>
>   Mark n2qt
>
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