[Elecraft] Filters OP1,OP2,etc.

[Ron D' Eau Claire]

> Trying to get the K2 back in working condition after the upgrade to 2.0.
> Can someone  explain the OP1 and the other OPs? Do they all have the same
> bandwidth and the BFO can be changed to tailor the pitch.?
>
> Alex N4BYJ

All of your filter, BFO, etc., settings should have  been preserved when you
installed the Rev 2 firmware. If you lost them, something didn't happen
right!

In any case, OPT1 is the filter on your SSB adapter board. It is the only
active "OPT" filter that I know of at this time.

If you have the SSB board installed, OPT1 will come up in filter position 1
for CW because it makes a very nice wideband filter for casually tuning
across the CW frequencies.

The bandwidth of the OPT1 filter is fixed. All you can do is adjust the BFO.

The BFO is set up as described in your KSB2 manual. The BFO setting for OPT1
in FL1 position is ALWAYS used for transmit. So that one is critical for the
proper sound on the air.

You can then use OPT1 in the other filter settings (FL2, FL3, etc.) with
different BFO settings to simulate a sort of "passband tuning"
characteristic by shifting the relationship of the passband to the BFO. This
will not affect your transmitted signal sound. The K2 reverts to the
FL1/OPT1 BFO setting for transmit regardless of the filter being used for
receive.

Ron AC7AC
K2 # 1289