[Elecraft] K2 drift

Sun Apr 12 02:33:33 EDT 2015

The fact that the pitch sounds very low when you centre the signal in the passband filter indicates a BFO problem, not a VCO/PLL problem.

73,
Matt VK2RQ

> On 12 Apr 2015, at 3:15 pm, Bernie KF0QS <hamdan at ix.netcom.com> wrote:
> 
> Don:
> 
> When I switch to a filter, I can't hear the signal I had centered in 
> the passband.  I can only hear the signal if I tune about 1 khz down, 
> and then I do hear the signal, albeit very low in pitch as opposed to 
> the pitch I heard before I switched in the filter.
> 
> Given that, I suppose it sounds like the VFO is the problem?
> 
> Bernie
> 
> At 11:10 PM 4/11/2015, Don Wilhelm-4 [via Elecraft] wrote:
>> Bernie, Again, I ask - does the audio pitch change when the signal 
>> is centered in the CW filter? If that changes, then the problem is 
>> with the BFO. If the audio pitch is the same at the filter center, 
>> the the shift is due to the PLL/VCO. 73, Don W3FPR On 4/12/2015 
>> 12:46 AM, Bernie KF0QS wrote:
>>> It only shifted that far with regard to the cw filters. > > On 
>> QSO's, it's only noticeable on long QSO's apparently.  I've never > 
>> noticed it myself, but I've had two hams point it out to me, both > 
>> during long QSO's. > > At 04:59 PM 4/11/2015, vk2rq [via Elecraft] 
>> wrote: >> You say it is shifting by as much as 1kHz? That is 
>> definitely not >> normal. My K2 built last year will only drift by 
>> around 20Hz or so >> as it warms up, it is pretty stable. The BFO 
>> inductor is L33, the >> pre-wound one that sits on a rubber bumper. 
>> Wasn't there a thread >> some time last year where someone was 
>> having problems with BFO >> frequency stability, and it turned out 
>> there was some contaminant on >> the rubber bumper that was making 
>> it conductive? 73, Matt VK2RQ >>> On 12 Apr 2015, at 1:13 am, 
>> Bernie KF0QS <[hidden email]> >> wrote: > > Dear OM's and YL's: > > 
>> Twice, I've had people tell me >> my K2 (which I've had on the air 
>> for over 3 > years) drifts a bit >> in frequency.  Both times have 
>> occurred during long > QSO's so it >> appears to be a slight 
>> drift. > > This phenomenon may also explain >> something else that 
>> happens.  Whenever I > set up the filter >> settings, they work 
>> well for a while.  After a while, the > sweet >> spot (i.e., the 
>> point at which the heard signal is in the middle >> of > the filter 
>> bandpass) seems to migrate eventually to about 1khz >> below > 
>> wherever I set it (at least that's where I have to move the >> RIT 
>> to hear the > signal when I switch in the filters).   > > Is >> 
>> there a common fix for both these problems, or am I experiencing >> 
>> two > different things.  Any help you can give would be >> 
>> appreciated. > > 73 de Bernie, KF0QS > > > > -- > View this 
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