[Elecraft] K2- frequencies

[Don Wilhelm]

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