[Elecraft] e: Using K3 with CW Skimmer

[Edward R Cole]

Pete, Joe and all:

I am not running CW Skimmer so this post is a little OT, but I do run 
the LP-Pan with MAP65 (JT65B).

For good info go to: http://www.telepostinc.com/LP-PAN.html#faq
Scroll down till you see LP-PAN Manuals and chose the version for 
your unit serial number.
e.g. S/N 514-799 page-24 has the Circuit description which ought to 
help understand the LP-Pan.
Page 26 shows the schematic.

For the K3 1st IF=8.215 MHz, the LP-Pan LO =32.836 MHz which counts 
down to 8.209 MHz which imparts a 6-KHz shift to suppress LO 
leakage.  I had to request the original xtal=32.860 MHz to correct 
this as it shifted my MAP65 frequency too far to be correctable by 
the sw.  That does leave me a center carrier artifact but I do not 
operate there so it doesn't matter.  I did have to swap I/Q to have 
sw operate properly.

Actual frequency of the xtal LO may be off exact frequency a little 
(maybe a couple hundred Hz) but that should not affect most users.

If you are curious how I am using the LP-Pan with my K3, go to:
http://www.kl7uw.com/LINRAD.htm

This also has the instructions on how I added IF output from my KRX3 
sub-receiver.
near the top are links to LP-Pan website and manual.

Hope this is helpful.
73, Ed - KL7UW


------------------------
From: "Joe Subich, W4TV" <lists at subich.com>
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Using K3 with CW Skimmer
Message-ID: <54D2A552.6010605 at subich.com>
Content-Type: text/plain; charset=utf-8; format=flowed


Pete,

LP-Pan does not use an 8125 KHz crystal to prevent the oscillator
leakage from getting back into the K3 IF strip and to offset the
"DC spike" from many sound cards.  The crystal used divides down
to approximately 8131.6 KHz which results in the audio frequency
being shifted by -6150 Hz (+/-).

It's been a while since I looked at the LP-Pan schematic/details
so the numbers may be off a bit.

73,

     ... Joe, W4TV


73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
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