[Elecraft] K2 filter alignment question

[Don Wilhelm]

LS,

That method works, but it suffers from the fact that finding the actual 
filter center frequency is difficult to do.  As the filter width is 
changed, the lower and upper skirts do not change at the same rate  - 
that is the main problem.  Yes, you are correct that in 1999 tapping the 
DISPLAY button did not display the BFO frequency.

There were many attempts back in 1999 to figure out a god way to align 
the K2 filters with better precision.  Then one day, someone mentioned 
Spectrogram - the visual displays provided by Spectrogram gave better 
results with less difficulty than any other method that had been tried 
before.  After several passes using Spectrogram in different ways over 
the next year or so, the current methods for using Spectrogram were 
evolved.  The latest information is on the Elecraft website documents 
(mostly by Tom Hammond N0SS), and Tom has a lot more information on his 
website www.n0ss.net.  The K2 Dial Calibration article on my website 
attempts to pull this information together along with the procedure for 
setting the K2 Dial Calibration - take a look at www.w3fpr.com for details.

73,
Don W3FPR

lstavenhagen wrote:
> Hi all,
> Not meaning to add to the wealth of info already on this topic, but I have a
> specific question about the "setting up your CW filters for the tonally
> challenged" article on the elecraft website.
>
> Specifically, part of the instructions in it to read the BFO frequencies
> after audibly finding the passband centers for each filter width. It
> instructs you to switch to Rev to get it to display the BFO freq. rather
> than the BFx number. My question is, why not just hit Display which shows
> the freq. already? I see the article was written in 1999, was there not the
> Display capability in the older K2's?
>
> Reason I ask is I decided to revisit my filter alignment (partly for an
> educational exercise to learn how this all works) and after fighting with a
> spectrum analyzer (iSpectrum on the mac, which just got me way off each
> time) I abandoned ship and tried this method. I was all set to put
> Spectrogram on my work machine and use that instead to try again but this
> seems to work far better.
>
> By doing it with the displayed frequencies, I got the filters utterly nailed
> in both normal and reverse simple as pie (after once doing the math wrong
> and aligning each one on the wrong side hi hi, like I said a great learning
> experience). If I want to change the pitch of the sig, I just push a pencil
> on the numbers and viola I have all the settings....
>
> Just wondering if this is too easy and I'm doing something wrong hi hi?
>
> 73,
> LS
> W5QD
>   
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