Strangebehaviour with WSJT

Paul F6EXV

Hi all
I am using SmartSDR version 2.4.9 on a Fex 6500, and WSJT-x version 2.0.0
When WSJT-x goes on transmit, it QSY 1 KHz .
So obviously, if I set WSJT to reply to the DX station on his own frequency, I will in fact be 1 KHz down.
So far, the only solution I found was to loch the receive frequency, but why is this happening, and where can I solve this a "normal" way ?

Andreas Junge

You probably have Split Mode "Fake" enabled in the WSJTX radio setup.

WSJT will QSY on TX and shift the audio tone accordingly. You are still on the correct effective frequency. 

The fake is usually for radios that have less than 3KHz of usable passband available. 

Andreas, N6NU 

Paul F6EXV

Hello Andreas
Yes, that was it...
When am I supposed to use fake split ?

Dave Spencer

Paul,
I use "Fake it" all the time. WSJT-X moves frequency on transmit to keep the transmitted signal in the middle of the passband and enables maximum power output. If you TX close to the passband edges without "fake it", you may find the power output drops off. You're still TXing where you wanted to in the first place.

Andreas Junge

Paul,

I think WSJTX is insisting on "fake" split when in Fox/Hound mode to increase the usable bandwidth. It's not really required on a Flex since the filters are not physical with limiting skirts, but WSJTX does not know that. Just make it happy and select "fake" :-)

Andreas, N6NU

Paul F6EXV

Thanks ! Now all OK !
73
Paul