[Elecraft] Crystal Filter Offset in 4.81, What does it mean?

[Wayne Burdick]

This just establishes the low-pitched rolloff by adjusting the filter position relative to zero-beat.

Setting it to 0.1 or 0.2 (the default) will have the least impact on the CW passband. 0.1 provides better low-end audio. 0.3 is for cases where you have such extreme signals that you need to lop off a bit more of the low end to eliminate any vestige of low-pitched opposite-sideband signals. For 99% of users, 0.1 or 0.2 will suffice.

Shifting the crystal filter center frequencies should not be necessary. I recommend just sticking with the offsets printed on the filters (0.00 for all 8-pole filters).

73,
Wayne
N6KR

On Feb 5, 2014, at 5:40 AM, Mike K2MK <k2mk at comcast.net> wrote:

> I installed the 4.81 beta firmware and I am able to change the crystal filter
> offset as described in the firmware notes. I can hear slight differences in
> a CW signal between 0.1, 0.2, and 0.3 KHz. What I don't understand is what
> does it mean. Previous to this release I would have assumed that the crystal
> filter is centered on my chosen CW pitch suggesting a 0 KHz offset. If I
> choose one of the 3 offsets am I now listening (and transmitting) slightly
> off zero beat. Why would I want this? Wouldn't I also want a 4th choice of 0
> KHz?
> 
> Explanations in layman's terms would be appreciated.
> 
> 73,
> Mike K2MK