CAT command for one slice changes frequency on this slice and another (4.1.5)

Carsten G0SYP · December 2025

I am using SmartSDR 4.1.5 on Windows 11 with my Flex 6600M in SmartControl Mode.

I usually have 3 panadapters running:

Panadapter 1 with 6m and Slice A for CW/SSB

Panadapter 2 with 6m and Slice B for FT8

Panadapter 3 with 2m and Slice C and D for FT8 and MSK

I sometimes close Slice A on Pan1 and add it to Pan3 if there is good Tropo or similar to be able to run traditional modes while still monitoring the digital frequencies and move it back afterwards.

My JTDX instances for FT8 are set to "Fake It" for split which means that it sends a CAT command to change frequency depending on my TX Audio frequency. CAT is using separate TCP Ports (except Sice D which is using a virtual COM port for MSHV).

This has always worked fine. Now recently I again moved Slice A from 6m to 2m as above. But now when I transmit on Slice C it also changes the frequency of Slice A to the same (so say 144.1725 on TX and then to 144.174 on RX).

I've tried restarting the Radio and SmartSDR several times, also restored a known profile but the link is still there. Sometimes it is Slice B that causes another slide to QSY. I haven't found a consistent rule. I also can't see any setting that would cause this (DIV is off!).

Has anybody seen this before?

73 Carsten G0SYP

Carsten G0SYP · January 3

Looks like a factory reset has resolved the issue. I had done one after upgrading to 4.01 and it was working then. Anyway, all fine now.

Tom C · December 2025

Carsten, I have had a similar problem but found it was caused by n3FPJ logger. If I had the wrong slice active it would QSY. I was using transverters on 2200 and 630 meters. Once I figured it out I worked around it. I hope yours is as easy to fix

Tom

N9RU

Carsten G0SYP · January 1

I've checked that but after disconnecting the logging program (which is only connected to Slice A)

I have found which VFO is being followed. Whichever VFO has the TX focus is followed. I am not sure what determines which VFO follows. So if TX focus is set onto VFO A, frequency changes are not followed but of course in practice, the TX focus will always change to the Slice I am operating on. (I should have mentioned that Auto Switch TX is enabled for all CAT ports)

Still looking for a solution.

73 Carsten G0SYP

Geoff AB6BT · January 1

I found that N3FJP ACLog caused odd behaviour in another situation.

I had 2 slices open one for FT4 and one for FT8 both on 15 meters. I had the FT8 slice configured as TX and the FT4 slice as RX.

When I transmitted using FT8 the transmission was terminated at the end if the FT4 period. It was not usable.

I asked Scott, N3FJP, about it and he had no soluton.

Carsten G0SYP · January 2

Further update - I think I have found what the behaviour is:

Of the 4 slices, one is the active slice (selected by clicking on it) and one is the TX slice (where the TX is highlighted in red). If a CAT command for frequency is sent to the TX slice, both the TX slice and the active slice move to that frequency.

A CAT command to any non-TX slice only moves the frequency of that slice, and if the TX slice is also the active slice it also only moves that slice's frequency.

CAT command for one slice changes frequency on this slice and another (4.1.5)

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