[Elecraft] Strange K2 Behavior?

[Eric Swartz - WA6HHQ, Elecraft]

This is a known out-of-band birdie on the K2 and has always been there.  

Part of our design goal on the K2 was to place any strong mixing products lile this outdie the ham bands. 

All superhet receivers will have birdies. Fortunately most are quite weak and are usually covered by band noise. This strong one was unavoidable and we purposely adusted the synthesizer and bfo parameters to place it outside the ham band.

73,

Eric  WA6HHQ
_..._
-----Original Message-----
From: w9cf <w9cf at ptolemy.la.asu.edu>
Date: Friday, Oct 17, 2008 12:29 am
Subject: Re: [Elecraft] Strange K2 Behavior?
To: elecraft at mailman.qth.net


Mine does that too. The VCO for a frequency around 14.360 MHz should
be running aabout 19.274 MHz and the reference oscillator runs at about 
12.096 MHz.  2*19.274-2*12.096 = 14.356 MHz, so that seems to be the
culprit. It pops in because of the way the VCO is tuned. When you get to the edge of the fine tuning, the U4 tunes the VCO to the next 5KHz 
coarse step and U5 changes the reference oscillator back to the beginning of a fine step. For the previous coarse step the birdie is not heard, but for this coarse step the two
oscillators are tuned so that it is. On my K2, with the way I have RTTY set up, I can hear it pop in on RTTY at 14361.5 and then it pops out at the next coarse step at 14366.5

73 Kevin w9cf


Brian Mury-3 wrote:
 
 On Wed, 2008-10-15 at 19:34 -0600, Michael Lewis wrote:
> band. I actually tuned out of 20m by a little bit up to 14359
> (14359.03 on the display to be exact) and BAM! I got an S9 tone. It
> goes from totally quiet to S9 as soon as the tuning display hits
> 14359.03. happens with no external antenna.
 
 I just tried it and I get the same thing. Starts at exactly:
 
 14359.03 USB (I assume you were using USB?)
 14360.80 CW
 14359.25 CW reverse
 14361.74 LSB
 14361.50 RTTY
 14358.53 RTTY reverse
 
 It behaves exactly as you described. It always starts suddenly then
 gradually tapers off in strength while tuning to higher frequencies.
 
 
 
 _______________________________________________
 Elecraft mailing list
 Post to: Elecraft at mailman.qth.net
 You must be a subscriber to post to the list.
 Subscriber Info (Addr. Change, sub, unsub etc.):
  http://mailman.qth.net/mailman/listinfo/elecraft    
 
 Help: http://mailman.qth.net/subscribers.htm
 Elecraft web page: http://www.elecraft.com
 
 

-- 
View this message in context: http://n2.nabble.com/Strange-K2-Behavior--tp1339332p1344229.html Sent from the Elecraft mailing list archive at Nabble.com.

_______________________________________________
Elecraft mailing list
Post to: Elecraft at mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft    

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com