Re: Can't get my uBitX to transmit CW on the Dial frequency

Tim Gorman


It would actually make the most sense to me if *both* the TX and RX
frequency stayed the same, only the BFO would be shifted. If you are
working CW on 7030 the both the TX and RX should show 7030! If you
change from CWL to CWU only the BFO should move. Otherwise you wind up
continually having to do math in your head to determine what frequency
you are actually listening to!It's far easier and quicker to make the
rig do that!

tim ab0wr

On Thu, 14 Jun 2018 18:19:42 -0700
"Michael Babineau" <@ve3wmb> wrote:

I have confirmed the same thing in the CEC firmware V1.08.  The uBITX
display frequency is the RX frequency not the TX frequency.

I will now explain why this is a problem.

This is not theoretical .. I tried this with my Flex-1500 with both
rigs side-by-side, TXing into dummy loads. 

My Flex is transmitting on 7.030 Mhz CWU exactly (dial frequency BTW)
using a 700 Hz RX offset. The uBITX is on CWU has a 700 Hz sidetone
set (ie offset) then the dial on the uBITX needs to be at 7.029.300
Mhz  so that it is receiving a the Flex with a 700hz audio tone. Both
stations can hear each other with a 700 Hz tone. This confirms that
the uBITX dial frequency is the receive frequency not its transmit
frequency.  I can also see and hear that the uBITX is transmitting on
7.030 Mhz with this dial setting.

Now I switch the Flex to CWL without changing frequency. I leave the
uBitx on the same frequency (7.029.300 Mhz) and still on CWU. Both
stations can still hear each other with a 700 Hz tone. Changing modes
on the Flex left the TX (dial) frequency the same and only moved the
RX frequency of the Flex to the other sideband (ie. the Flex RX
frequency switches from 7.029.300 Mhz to 7.030.700 Mhz). 

I put back Flex back on CWU without changing frequency (ie. dial
still shows 7.030 Mhz). Now switch I the uBITX from CWU to CWL. The
dial frequency on the uBITX still shows 7.029.300 Mhz on the dial but
it is now transmitting at 7.028.600 Mhz and is inaudible to the Flex
which is still listening at 7.029.300 Mhz !

With any rig in CW mode, when you have a station tuned in and are
listening you should be able to switch from CWL to CWU at at any time
and without retuning and you should be able to hear the other station
and he should still be able to hear you. The whole idea of switching
sidebands in CW mode is to be to use it as a means of avoiding
adjacent noise. Sometimes switching from CWU to CWL will allow you to
avoid QRM. 

That is only possible if the uBITX TX frequency remains fixed on CW
sideband changes (CWU/CWL) and the RX frequency changes according to
the sideband selected and the configured offset.  

So that means that the display frequency since it is fixed, must be
the TX frequency. The RX frequency should change on switching from
CWU to CWL based on a minus or plus offset from the TX frequency. 


Michael VE3WMB

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