MultiFLEX with two users on FT8 Different Bands

Bart Haynes · March 2020

I have two (2) Towers 1,000 feet apart, myself and a friend want to be operating remotely (MulitFLEX) on FT8, each to his own tower on 2 different bands, one TX on even cycle the other on the odd cycle. I'm trying to figure out how to do it using a Flex 6700 and a Power Genius running JTDX. Presently CW is no problem but using FT8, the JTDX program transmits on the same freq on both remote operations.

Thanks for the help.

Bart

Al K0VM · March 2020

this may help from WSJT-X FAQ...

How should I configure WSJT-X to run multiple instances?

Start WSJT-X from a command-prompt window, assigning each instance a unique identifier as in the following two-instance example. This procedure will isolate the Settings file and the writable file location for each instance of WSJT-X.

wsjtx --rig-name=TS2000  wsjtx --rig-name=FT847    rig name could be east tower & west tower...    AL, K0VM

Steve Sterling · March 2020

I've done it (SO2R only) but there are complications. 1st-- "normal" FT8 runs in 15 second intervals, transmitting for 15 seconds then receiving for 15 seconds. There is only one transmitter in the 6700 (or any Flex) so only one user can be transmitting at a time whilst the other user is receiving. Thus the two computers in two shacks each running WSJT-X would need to be using a common time source (to a few milliseconds) so both weren't trying to xmit at the same time and would need close coordination between the users "I will take the even time slot, you take the odd".
2nd- since one user will be receiving when the other is transmitting, you would need to set up the 6700 for full duplex. Not hard for radio settings but obviously your antenna and bandpass filter situation must be perfect or you run the risk of dumping amp-level watts into a receiver.

Radio is capable.

Paul - K6HR · March 2020

Hi Bart,

If the two WSJT-X instances are running on different bands, and antennas have 1000 ft separation. You should be fine. I've done what you describe, running two instances of WSJT-X, with antennas much closer (on a small city lot) and everything worked fine as long as they had their time synced and worked on even and odd intervals. I ran mine on the same PC but if you use something like Meinberg for sync on both PC's you should be fine. As I was. The 6700 is protected from high RF input and will immediately tell you if that is a problem. It was never a problem for me even on the small sized property. However I was always on different bands and utilizing the FDX feature.

I am not sure what you meant "but using FT8, the JTDX program transmits on the same freq on both remote operations"

As long as the dual OP's agree to stay on different bands, as stated earlier by Steve, the 6700 is capable.

Bart Haynes · March 2020

Thank you to all that replied, we have decided to play it safe for now and only operate one at a time on different bands and stay on the same band when working together. Thanks again for all your replies and by the way, the FDX fixed the issue with controlling JTDX on both remote computers.

MultiFLEX with two users on FT8 Different Bands

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