[Elecraft] Tuning noise on K2 - 40M

[Geoffrey Mackenzie-Kennedy]

Many thanks for the lead. Strangely the frequency separation between 
adjacent clicks seems to be related to the number, separation and strengths 
of strong received signals. Also on occasion when tuning through a 40m BC 
station whose received carrier level is in the region of -10dbm, the 
receiver will lock onto the BC signal and not let go until it has been tuned 
further a few kHz, typical is approx 3 kHz and always (I think) down in 
frequency, then a 'plop'. This is why I have the *suspicion* previously 
mentioned.

73,
Geoff
GM4ESD

----- Original Message ----- 
From: "Kevin Schmidt" <w9cf at ptolemy.la.asu.edu>
To: <elecraft at mailman.qth.net>
Sent: Monday, February 12, 2007 9:06 PM
Subject: Re: [Elecraft] Tuning noise on K2 - 40M


>
> I think this is the known "feature" described by Wayne in:
> http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-03/msg01007.html
>
> 73 Kevin w9cf
>
>>My K2 also produces clicks on 40m which disappear if the antenna
>>is disconnected or turned away from strong BC stations above 7100
>>kHz. Running CAL PLL has not cured the problem, and I have since found
>>the same problem on 15m. It might exist on other bands but I have not
>>had the time to check. I have a *suspicion* that strong signals from the
>>antenna / banspass filters reach the VCO and Reference oscillator area
>>of the RF board by some direct route, not via the Preamp / attenuator /
>>mixer and momentarily 'upset' the VCO causing the click. The VCO (VFO)
>>could be upset if some product produced by multiple mixing attempted to
>>take over control of the loop, sometimes a problem with locked loops. But
>>I cannot confirm this yet due to lack of time at the moment.
>>
>>73,
>>Geoff
>>GM4ESD