FT-8 Slice Issues - Flex 6400

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  • Updated 2 years ago
While on FT-8 last evening with only slice A open on my Flex 6400, slice B unexpectedly opened on the PC monitor.  Worse yet, slice B took began to transmit instead of slice A, which had been in use. Fortunately, I quickly halted the FT-8 transmission.

This morning, I replicated the entire scenario again. To my dismay, while only using slice A, that pesky slice B pops up and takes over the transmission.  No, I am not using the split function.
I did make a video of the scenario, which I can post as needed. However, I did pull together some screen shots to illustrate the problem.

I did see prior postings that this may have been due to a persistence problem, which was identified years ago and corrected during SmartDSR revisions. Not sure if this is the same problem, but I thought that someone may have some suggestions on resolving this problem.

The following screen shots depict the issues...

Slice A indicates the active slice (TX is lit).  Slice B shows rig is on 14.076.011

Absence of slice from where it should be located.


Upon tuning the rig using slice A on 14.074 mHz, slice B actually was transmitting on 28.280 mHz). The slice B flag indicates TX, however, slice A was in use when TUNE was selected. The SWR jumped to 2:1 from that occurrence. No ham though as the tune power was at few watts.

Lastly, I selected slice B as active, but slice A indicated TX on the flag.

Guys, any suggestions on resolving this?

Photo of K3WR - Jim

K3WR - Jim

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Posted 2 years ago

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Photo of K3SF


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My first reaction was to see how wsjtx configuration is setup.

If wsjtx was not running then what other s/w is running that can send commands to the radio?

i have seen similar mix up happens when i have wsjtx and my logging program connected to the radio both of which can send commands to the radio. Commands sent to the radio some times get out of sync.

Every time it has happened to me, it has been operator error.

one time i had two instances of wsjtx improperly configured as to were to send the transmit command. One was set right  and the other was set wrong. when i hit 'tune' in FT8..i saw the opposite slice transmit...combo of dax setup and command port selection in wsjtx setup wrong ...DUH

Now when i operate the radio, i am more like a pilot and do a pre-flight inspection of s/w settings/configurations during their startup phase....

may not be you situation or maybe again could be something similar.

Photo of Pat N6PAT


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I've seen this before when you open an instance of WSJT-X that is configured with a DAX different from the current slice (in your case slice A)

For example:

If you have slice A open with DAX 1 and then launch WSJT-X and it is configured for DAX 2 it may open Slice B if Slice B was last set to DAX 2.

I have had this happen to me before on my 6700. It doesn't happen all the time. I've only experienced this twice so far.

To avoid this I have 4 different desktop icons. One for each instance of WSJT-X with each configured to a different DAX. I always check the current slice DAX assignment before opening the corresponding WSJT-X so I know they match

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K3WR - Jim

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Thanks guys for the suggestions.  The Flex 6400 is just fine.  Problem was in the WSJT-X application.

Never ever check "Split Operation" as in the example below. Not good!
Leave the selection as "None".

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I believe that that information on configuration was posted in one of Ria's posts a while back on wsjt configuration which was very helpful.