[hpsdr] HPSDR Transmit Frequency

[Joe Martin K5SO]

Merv,

Perhaps part of your confusion stems from this:

1)  If you set 14.310000 MHz into VFO A and have USB selected you will  
transmit as I noted in the previous email.

2)  If, without changing the VFO A setting, you then select CWU to  
operate CW instead of USB, your transmit frequency will be 14.310000  
MHz + the CW offset pitch frequency you have put into the  "Pitch Freq  
(Hz)" window on the front panel and the VFO A indication will be  
updated to show 14.310000 MHz + the offset.

This "offset" behavior is there so that if you were operating voice  
(USB) on 14.31000MHz and switched to CW to communicate in CW with the  
person you were just talking with via USB he will be able to hear you  
with an audio tone equal to your "Pitch Freq (Hz)" setting while he is  
still in USB  receive mode.  If your CW transmission were sent exactly  
on 14.310000 MHz the receiving station will not hear you unless he  
"down tunes" away from 14.310000 MHz because if you transmit exactly  
on 14.310000 MHz he will be "zero beat" with your transmit frequency  
and will not hear any CW keying from you.   The offset behavior  
automatically takes care of the "BFO" function that is found on old  
analog radios.

Now,  if you happen to have a pre-arranged CW sked set up with some  
station and you have an agreed-upon operating frequency of 14.31000  
MHz, you will want to first select CWU then set the VFO A to 14.31000  
MHz.  In this case you will be transmitting exactly on 14.31000 MHz.

I hope this helps you understand the behavior better.

73,  Joe K5SO


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