[Elecraft] Re: K3 in SS Phone

[wayne burdick]

One of the variable-passband filters we've been considering is one for 
SSB, with a range of about 1.4 to 2.2 kHz. It would have 5 poles rather 
than 8, but I'm sure it would work well in combination with the I.F. 
DSP. The MCU would automatically dial in the crystal filter bandwidth 
to match the DSP.

This would be a slot-saver for those want multiple SSB RX bandwidths. 
Once the CW variable-passband filter was also ready, you might have:

    FL1  6.0 kHz
    FL2  2.7 or 2.8 kHz
    FL3  1.4-2.2 kHz (SSB variable passband crystal filter)
    FL4  0.4-0.8 kHz (CW variable passband crystal filter)
    FL5  200 Hz

Variable filters covering a wide range will have slightly greater 
ripple than fixed filters when they approach either end of their range, 
so we'd only use them in receive mode. In the example above, FL2 would 
be used for SSB/CW/DATA transmit and FL1 for AM transmit. Those who 
wanted FM and were less concerned about the narrowest possible CW/DATA 
bandwidths could shift all of the filters down one slot, bumping out 
the 200-Hz filter.

73,
Wayne
N6KR

On Nov 19, 2007, at 11:37 AM, Ed Muns wrote:

> If there were a 1.5kHz filter available, I might consider it....

> ---

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