[Elecraft] K2 Filter Alignment

[Don Wilhelm]

Bernie,

It is good to hear that you have found success.

As far as the filter alignment "instability" that you have alluded to, I 
think that impression has other causes - lack of properly zero beating 
for one.

I have recently worked on 3 K2s that I had aligned 3 to 5 years ago, and 
I find that the settings did not change.  The K2 alignment and 
calibration settings are quite stable and do not drift over time once 
they are properly set.  Do it right and it will stay put for a very long 
time.

For additional information about setting the filters (and dial 
calibration) on your K2, please refer to the K2 Dial Calibration article 
on my webpage at www.w3fpr.com.

73,
Don W3FPR

On 1/15/2013 11:33 PM, Bernie KF0QS wrote:
> Don:
>
> Thanks for your reply.  I have to admit that I had completely forgotten the
> "spot" function.  I guess my ear was attuned to something different from
> what the spot function would show.  I have found that, if I use the spot
> function, I am able to keep the received signal within the passband of the
> filter in use.
>
> I did recheck my dial calibration, and I did the filter alignment all over
> again.  It now seems to work fine.  Indeed, I gave it a bit of an acid test
> during the North American QSO Party last weekend.  I would tune into one of
> the most crowded frequencies, get a signal in the middle of the passband for
> one of the narrower filters (I do now understand that the filters are
> 1500khz, 700, 400 and 200khz - sorry for the error), and then try and reply
> to that signal.  It worked perfectly every time.  In other words, a signal
> in the center of the filter passband was pretty close to my transmitted
> signal.
>
> I wanted to wait a bit before replying because, on a few past occasions when
> I realigned the filters, the filter alignment seemed to change as time went
> on.  In other words, the received signals seemed to end up more and more out
> of the passband as time went on.  However, at this point, two weeks after I
> did the latest realignment, everything seems stable and working well.
>
> Thanks so much for your patience and help.
>
> 73 de Bernie, KF0QS
>