Report preparation
What happened?
When operating FT8 (or other WSJT-X digital modes) via TCI rig control, WSJT-X is configured with Split operation = Fake it. During a transmission WSJT-X shifts the VFO to the TX audio frequency — for example, from 18.100 MHz to 18.101 MHz — to place the transmitted signal at the correct offset within the FT8 passband.
After the transmission ends and WSJT-X releases PTT, the slice frequency does not reliably return to the original RX frequency (18.100 MHz). Intermittently — roughly every few transmission cycles — the slice remains parked at the TX frequency (18.101 MHz). On the next decode period, WSJT-X and AetherSDR are now both tuned to the wrong frequency, causing the RX passband to drift upward by one TX audio offset increment per affected cycle. Left uncorrected, this compounds across multiple transmit/receive sequences.
This behaviour is specific to TCI rig control. With rigctld (Hamlib NET) rig control and "Fake it" split, the frequency returns correctly after every transmission. The bug does not occur when WSJT-X Split operation is set to None with TCI — however, that workaround prevents WSJT-X from placing the TX signal at the correct audio offset within the passband, which impacts FT8 operation.
What did you expect?
After WSJT-X completes a transmission sequence and releases PTT, the TCI server should restore the slice to the pre-transmission RX frequency (18.100 MHz). Each TX/RX cycle should be idempotent with respect to VFO frequency: RX frequency before TX must equal RX frequency after TX.
Steps to reproduce
Connect AetherSDR 0.9.6 to a FLEX-6600 (fw 4.2.18.41174) on Windows.
Set the slice to DIGU mode, tune to an FT8 frequency (e.g. 18.100 MHz on 17m).
In WSJT-X 3.1.0 Improved, configure:
Rig: TCI Client RX1
TCI Server: 127.0.0.1:50001
Split operation: Fake it
Confirm WSJT-X is decoding FT8 signals correctly.
Enable auto-sequencing and allow WSJT-X to complete 3–5 full TX/RX cycles.
Observe the AetherSDR VFO frequency after each TX period ends.
After at least one transmission, the slice frequency remains at the TX offset (e.g. 18.101 MHz) rather than returning to 18.100 MHz.
Subsequent decode periods show WSJT-X and AetherSDR both tuned to the wrong frequency.
AetherSDR version
0.9.6
Radio model & firmware
Flex 6600 v4.2.18
Operating system
Windows
OS version and hardware
Win11
Report preparation
What happened?
When operating FT8 (or other WSJT-X digital modes) via TCI rig control, WSJT-X is configured with Split operation = Fake it. During a transmission WSJT-X shifts the VFO to the TX audio frequency — for example, from 18.100 MHz to 18.101 MHz — to place the transmitted signal at the correct offset within the FT8 passband.
After the transmission ends and WSJT-X releases PTT, the slice frequency does not reliably return to the original RX frequency (18.100 MHz). Intermittently — roughly every few transmission cycles — the slice remains parked at the TX frequency (18.101 MHz). On the next decode period, WSJT-X and AetherSDR are now both tuned to the wrong frequency, causing the RX passband to drift upward by one TX audio offset increment per affected cycle. Left uncorrected, this compounds across multiple transmit/receive sequences.
This behaviour is specific to TCI rig control. With rigctld (Hamlib NET) rig control and "Fake it" split, the frequency returns correctly after every transmission. The bug does not occur when WSJT-X Split operation is set to None with TCI — however, that workaround prevents WSJT-X from placing the TX signal at the correct audio offset within the passband, which impacts FT8 operation.
What did you expect?
After WSJT-X completes a transmission sequence and releases PTT, the TCI server should restore the slice to the pre-transmission RX frequency (18.100 MHz). Each TX/RX cycle should be idempotent with respect to VFO frequency: RX frequency before TX must equal RX frequency after TX.
Steps to reproduce
Connect AetherSDR 0.9.6 to a FLEX-6600 (fw 4.2.18.41174) on Windows.
Set the slice to DIGU mode, tune to an FT8 frequency (e.g. 18.100 MHz on 17m).
In WSJT-X 3.1.0 Improved, configure:
Rig: TCI Client RX1
TCI Server: 127.0.0.1:50001
Split operation: Fake it
Confirm WSJT-X is decoding FT8 signals correctly.
Enable auto-sequencing and allow WSJT-X to complete 3–5 full TX/RX cycles.
Observe the AetherSDR VFO frequency after each TX period ends.
After at least one transmission, the slice frequency remains at the TX offset (e.g. 18.101 MHz) rather than returning to 18.100 MHz.
Subsequent decode periods show WSJT-X and AetherSDR both tuned to the wrong frequency.
AetherSDR version
0.9.6
Radio model & firmware
Flex 6600 v4.2.18
Operating system
Windows
OS version and hardware
Win11