[Elecraft] Re:Discrete Passband Tuning Revisited

[W3FPR - Don Wilhelm]

Whoops,
Folks, discrete passband tuning will work best by using the same fiilter 
width for all the filters - I had a slip of memory and temporarily forgot 
that the CW and CWr filters share the same bandwidth.
I guess discrete passband tuning could be something for the RTTY filters - 
now how do we get the sidetone offset integrated into the RTTY filters?  And 
how do we activate keying and other CW funtions in RTTY mode since that is 
really treated as a special case of SSB?  Problems, problems, problems. --  
for CW use it has to be the CW filters.

I am still going to try the discrete passband tuning as well - My current 
thoughts - leave FL1 wide but usable (1.0 kHz or 800 Hz). then go to 
passband tuning with FL2, 3 and 4 with a 400 Hz filter width; center FL2 at 
650 Hz, FL3 at 750 Hz, and FL4 at 550 Hz (assuming a 600 Hz sidetone).  That 
should allow a normal 400 Hz filter for crowded band use (FL2) plus the 
ability to drop a lower pitched interfering signal out with FL3 and a higher 
frequency interfering signal out with FL4.  Turn the centering for FL3 and 4 
around if you want to drop off the high end first and the low end with FL4. 
I assume most listening would be done with FL1 or FL2   This scheme should 
allow better rejection than a narrower filiter and avoid the attenuation 
that occurs with very narrow filters.

An extension of the above, one could use CWr to drop off the high frequency 
side and CW to drop the low frequency side (or vice-versa) that would still 
provide a wide filter for FL1 (but 2 BFOs), and 400 Hz for all the rest, 
giving the normal centered filter plus 5 shifted passband positions.  Let 
your imagination run wild and try it out.

73,
Don W3FPR

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

> W3FPR - Don Wilhelm wrote:
>
>>   Also, I seldom use the reverse sideband for CW, and
>> there is no reason that the BFOs have to be set for sideband reversal -
>
> As someone who has done a lot of playing with the K2's filters, tried 
> discrete passband tuning, etc., I have to say:
>
> Neat idea!  Why didn't I think of it?  Another passband position for each 
> filter width!
>
>