[Elecraft] K1 filter board question

[Mike Morrow]

Craig wrote:


>I bought both a 4-band and 2-band filter board for my K1. I built
> the 4-band board for 40, 30, 20, and 15 meters.

>I have parts to make the 2-band board either 80/17 or 80/15.

>What's really going to be involved when swapping boards? ...
>What about calibration?

The K1 MPU stores a display calibration factor for each HF (160m through
10m) band, not each filter board band.  When you calibrated your
40/30/20/15m board, the K1 stored the results for 40/30/20/15m.  If you
build a two band filter board for 80/17m and calibrate the display, then the
K1 will store the results for 80/17m.

After you swap in a two-band filter board, you must tell the K1 MPU which HF
band is assigned to K1 bands b1 and b2.  When you return to a four band
board, you must re-assign b1 and b2 to the appropriate HF band.  The K1
automatically uses the appropriate stored display calibration factor for the
HF band assigned to each K1 filter board band.

EXAMPLE:

If you remove your 40/30/20/15m board and install a 80/17m board, the K1
automatically detects that a two-band board in now in place.  Then you use
the menu to re-assign b1 to 80m and b2 to 17m.  The K1 automatically applies
the previously stored display calibration factors for 80m or 17m.

If you remove your 80/17m board and install a 40/30/20/15m board, the K1
automatically detects that a four-band board in now in place.  Then you use
the menu to re-assign b1 to 40 and b2 to 30m.  You won't have to change
anything for b3 and b4, since the K1 will remember that they had been
assigned to 20/15m when you first set up your four band board.

>They must be thinking I'm swapping two 2-band boards because
>4+2 is six bands to remember.

Just remember, the display calibration factor is stored in the K1 front
panel MPU for each HF band.  It doesn't matter how many bands your filter
board has, because once you tell the K1 MPU which HF band goes with each
filter board band, the appropriate display calibration factor for the HF
band will be used.

>Anybody else using this configuration

I use a 40/30/20/15m board and a 80/17m board.  I don't often swap boards,
but it's a nice feature to have anyway.

> and can tell me what all I'll have to do every time I switch boards?

Only two basic steps, anytime after you've initially calibrated and aligned
each board:

(1)  Physically swap boards.
(2)  Re-assign HF bands for b1 and b2.

That's it, no matter if it's a two-band or a four-band board swap!

NOTE:  You mentioned that you were considering building the two-band board
for 80/15m.  Your four band board already has 15m, and you have already
stored the display calibration factor for 15m in th K1.  The K1 can store
only one display calibration factor for each HF band.  If you install
another filter band board that also has 15m on it, when you assign b2 to 15m
the K1 will use the calibration factor that was based on the hetrodyne
crystal for 15m that was on your other filter board.  Unless the 15m
hetrodyne crystals on the two filter boards oscillate within about 100 Hz of
the same frequency, then the display will be somewhat inaccurate on the
second filter board that has 15m on it.  There's no way of getting around
this.  It's best to not duplicate the same HF band on multiple filter
boards.

73,
Mike / KK5F