[Elecraft] Tuning noise on K2 - 40M

[Geoffrey Mackenzie-Kennedy]

Dave,

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

----- Original Message ----- 
From: "Dave-Boat Guy" <anavig8or at yahoo.com>
To: <elecraft at mailman.qth.net>
Sent: Monday, February 12, 2007 1:58 AM
Subject: [Elecraft] Tuning noise on K2 - 40M


> Hi,
> I was tuning around on 40M this evening and noticed
> some clicks when I tuned from 7119.82 to 7120.00.  I
> started checking and I noticed this behavior from
> about 7050 through 7320...every 10 KHz.  If I
> disconnect my antenna this problem goes away.  The
> problem remains if I use the attenuator or change mode
> or filter settings.  Disabling the AGC or changing
> from slow to fast has no effect.  This appears to be
> only happening on 40M.
>
> Since the problem goes away when I remove the antenna,
> I'm wondering if it is due to some mixing product
> although it happens even when the band is quiet...but
> the antenna is connected.
>
> Any ideas?
>
> Thanks in advance.
>
> Dave