K2- frequencies

[Nick G3RWF]

Thanks for replies to my problem with filters - now sorted and I can hear the same signal on all filter settings!
Got watts coming out the back but no QSOs - I find that the transmit freq is more than 1 KHz lower than receive(which is about 2 KHz lower than the digital display. Can't find anything on the site to help but yet again sure I am doing something stupid.
Grateful for advice please(I have now finished building the K2 - now just trying to make it work. I could work split for ever but that isn't the plan!
73 Nick G3RWF
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[Don Wilhelm-3]

Nick,

It certainly sounds like you have the CW filters set to the wrong
sideband.  If you set the K2 to a band below 15 meters and use
Spectrogram while changing the BFO frequencies, you will find 2 places
where the passband lines up correctly with the audio frequency you
selected for your sidetone pitch.  On CW, set the BFO to the lower of
those 2 numbers (in the K2 display), and on CWr, set the passband to the
higher of the two numbers.

If you are curious about what is happening, say your sidetone pitch is
set for 500 Hz.  When the K2 receives in CW mode, the dial indicates the
carrier of the received signal minus your sidetone pitch setting.  Now
when you transmit, and you have the BFO on the high side of the signal
instead of the low, and the transmitted signal is higher than the
frequency indicated by the dial by 2 times 500 Hz or 1 kHz.  The K2
knows that the CW mode, it should subtract the sidetone pitch, and in
CWr the sidetone pitch will be added.  For this reason, you must set the
  BFO so the filter passband is on the correct side of the filter center.

If your filters have been so mixed up that you are totally lost, set the
BFOs to the values shown on page 89 of the manual and go from there.
After that, when using Spectrogram, be certain not to move the BFO
frequency so far that the passband goes through zero frequency (and
comes out on the other side which is the wrong sideband).

73,
Don W3FPR

Nick Henwood wrote:
> Thanks for replies to my problem with filters - now sorted and I can hear the same signal on all filter settings!
> Got watts coming out the back but no QSOs - I find that the transmit freq is more than 1 KHz lower than receive(which is about 2 KHz lower than the digital display. Can't find anything on the site to help but yet again sure I am doing something stupid.
> Grateful for advice please(I have now finished building the K2 - now just trying to make it work. I could work split for ever but that isn't the plan!
> 73 Nick G3RWF
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[Tom Hammond-3]

Nick:

>Thanks for replies to my problem with filters - now sorted and I can
>hear the same signal on all filter settings!
>
>Got watts coming out the back but no QSOs - I find that the transmit
>freq is more than 1 KHz lower than receive (which is about 2 KHz
>lower than the digital display. Can't find anything on the site to
>help but yet again sure I am doing something stupid.

Sounds as though there's still(!) an XFIL/BFO alignment problem.

1) Confirm that RIT (or XIT) has not been enabled.

2) What SIDETONE tone (ST P) have you selected?

3) Please send me the CAL FIL DAC (or frequency) values you now
    have for both CWN and CW REV. AND the values for the filter
    CENTER FREQ. (or DAC value) for each bandwith you've chosen.

4) On what band did you perform the CAL FIL operation? If you did
    it on on 15M or above, you MUST INVERT the 'sense' of the side-
    bands... e.g. CWN XFIL values will be ABOVE filter center
    instead of being BELOW, etc.  40M is probably the best band to
    use when performing CAL FIL.

Cheers,

Tom   N0SS


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