[Elecraft] CW filters

[Don Wilhelm]

Kieth,

If you are using Spectrogram to set your filters, try it this way (I suggest
also using a wideband noise generator, but 'dead band' noise will do - make
certain there are no active signals in the K2 passband):

First look at the Spectrogram display for FL1 (SSB mode) and pick a point on
the passband lower frequency edge (about 6 to 10 dB down from the peak) note
the audio frequency of this point - then set a Spectogram marker to that
frequency.

Then switch to FL2 and adjust the filter width to something reasonable for
SSB (maybe 1.8 kHz) and then set both BFOs (LSB and USB) so that the
passband crosses your marker frequency at about the same attenuation point
as it did on the OP1 filter display.  You should now be able to receive
intelligible SSB with FL2.  The response may be 3 to 6 dB lower than you
obtained with the OP1 filter, but that is the penalty one must pay for using
a filter that is optimized for narrow bandwidth work at a wide bandwidth.
Should the response be much less than 6 dB below the OP1 filter, you may
want to review your soldering and diode orientation on the SSB board -
especially in the area of the filter switching diodes.

Hope I didn't cause more confusion - if so, I can respond to your questions.

73,
Don W3FPR

----- Original Message -----

> I set up my cw filters and everything was fine until I installed
> my SSB unit. I set my filters according to the SSB manual but
> now I only get a very weak signal when switching to XFIL 2,3 and 4.
> I have read and re read the info on setting the filters but I am
> dazed and confused.
>