[Elecraft] Filter alignment question

[Don Brown]

Hi

Here is a way to check the alignment of the filters. Assuming a 600 Hz 
sidetone tune to 4.000 MHz in CW normal mode You should hear the 4 MHz 
internal oscillator as a 600 Hz tone, Switch to each filter and the tone 
should not change frequency by more than a few hertz. Then switch to CW 
reverse and go back through the filters. Again the 600 Hz tone should not 
change. To check the SSB filters select LSB and tune to 4.00060. You should 
hear the same 600 hertz tone then check each SSB filter and the tone should 
not change. Now change to USB and tune to 3.99940 MHz and check for the 600 
hertz tone on each filter. If you do not hear the correct tone on any of the 
above tests then you need to recheck the filter alignment for that filter. 
You may have it set on the wrong side of the filter slope or may need to 
move it slightly. Use spectrogram to re-align the filters after first 
setting them to the values listed in the manual so they are in the ballpark. 
You should move each filters BFO frequency slightly even if it is correct so 
the firmware will recalculate the sidetone offsets.

Don Brown
KD5NDB


----- Original Message ----- 
From: <info4mjs at att.net>
To: <elecraft at mailman.qth.net>
Sent: Monday, March 13, 2006 7:05 AM
Subject: [Elecraft] Filter alignment question


>
> Hi,
>
> I was monitoring the K2's local oscillator frequency and I noticed that as 
> I tune to WWV in the various modes, that the LO frequency is different at 
> zero beat.  I expected an offset (w/respect to SSB) in the CW mode but I 
> expected the LO to be the same at zero beat whether I was in LSB or USB 
> modes.  It isn't so I am wondering if something is not aligned properly.
>
> Any insight is appreciated.
>
> Thanks
>
> Mike, WA1SEO
> K2 4778
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