TX delay on WSJT-X in SSDR v3.5.8?

John, G3WKL

Upgrade the Flex 6600/Maestro radio at the National Radio Centre, Bletchley Park, this morning to the latest version, and came across something that I thought might be worthwhile sharing / discussing. Following a successful upgrade, there was a noticeable transmit delay running WSJT-X through the Maestro/6600 combination, with SmartCAT running on the Windows machine. This delay was new - the WSJT-X config was unaltered from the CAT control used for months/years with a Kenwood profile.

Changing the SmartCAT control from CAT to TCP, along with the appropriate change in the WSJT-X config, the TX delay was vastly reduced to acceptable levels, along with WSJT-X frequency changes being much quicker.

I suppose the TCP protocol is going to be faster than the CAT control, though it's unclear to me why it has worked well for so long. It also seems logical to me to use the FlexRadio 6xxx profile in WSJT-X, something I have done for a number of years with my home station.

73 John, G3WKL

Mike-VA3MW

The delay can on CAT can happen due to the processing and I suspect it has something to do with Windows and less with SmartSDR and WSJT. The delay may be related to some sort of timeout or flow control of the RS232 ports, again at the windows level.

If it was my station, I would turning off anything to do with Flow control on those serial ports within Windows Device Manager.

But, yes, using TCP is a more efficient way to communicate rather that RS232 which is a very lethargic method at times. :)

David Decoons, wo2x

Since virtual serial ports are still sent over TCP from SmartSDR CAT, it makes sense to use the Flex 6xxx virtual TCP port. Not sure what speed you had the virtual com port set to in WSJT-X but the virtual TCP port will run at fastest speed.

Last, when you performed the upgrade to 3.5.8, did you perform a cold boot of the radio and reboot the PC after the upgrade?

73

Dave wo2x

John, G3WKL

Thanks for your comments MIke and Dave. Much appreciated. Yes, I did a cold boot of the 6600 and restarted Windows following the upgrade.

73 John, G3WKL