[Elecraft] Re: BFO on KX1

[Wayne Burdick]

"C. GONDARD" wrote:

> I performed the BFO calibration (see page 69 of the manual) with WWV on 10
> MHZ. I was able to reach a good balance between LSB and USB with a BFO
> parameter of 57....

Chris, 

I haven't noticed any offset error due to BFO calibration. I'll certainly look
into it if warranted. Your BFO parameter (0.57 kHz) is much higher than any I've
seen before, possibly indicating a component problem in the BFO, or incorrect
adjustment. -0.2 kHz is more typical, 

I also want to make sure you know what to expect in each mode (CW, USB, LSB)
when checking using an external transceiver. The differences between these modes
are explained on page 66 of the manual (and reiterated below). The "BFO" menu
entry applies to all three modes.

The most important difference from a CW operating standpoint is where the offset
is introduced. But there always *is* an offset, so you can make CW or CW/SSB
cross-mode contacts in all three modes.

In CW mode, the KX1 firmware uses an offset equal to 600 Hz during receive. This
means that if you listen to a received signal at a pitch of about 600 Hz, your
VFO will equal the other station's carrier frequency. You should also be very
close to their carrier frequency when you transmit.

In LSB and USB modes, there is no receive offset, so that you can zero-beat
signals to determine thier carrier frequency. This is useful when listening to
SSB or AM stations. But of course for CW use, you'll still listen to about a 600
Hz pitch, so the VFO will be "off" in this case by about this amount. The 600 Hz
CW offset is then introduced on transmit. SSB stations would hear your
transmitted signal at a 600 Hz pitch, and CW stations will simply hear you at
the correct frequency. 

I'll re-test all of these with a simulated BFO offset that's similar to what you used.

73,
Wayne
N6KR


-- 

http://www.elecraft.com