locked Re: After upgrade to WSJT-X 2.4.0, an IC-7600 no longer changes bands on SPE Expert 1K-FA power amplifier #Cat_RigControl

Frode Igland

This regrettably late reply responds to comments by Allan ZS1LS in Digest #2090 on 25 August 2021, and by Bill G4WJS and Mike W9MDB in Digest #2075 on 20 August 2021.

In our club station, we have now made more extensive examinations of the latest versions of WSJT-X and how they work with the IC-7600 and SPE Expert amplifiers.

The setup was:

  • Softwares: WSJT-X 2.3.1, WSJT-X 2.4.0, WSJT-X 2.5.0-rc5;
  • Radio: IC-7600 (firmware 2.0);
  • Amplifiers: SPE Expert 1K-FA and SPE Expert 1.3K-FA both set to “ICOM” Cat control.

The HP computer is connected to the radio via USB A-B cable. The radio is connected to the PA via the CI-V socket on the radio to the DB-15 CAT socket in the amplifier, as well phono plugs from the “Send” and “ALC” sockets on the radio to the “Relay”/”RY1” and “ALC”/”ALC1” sockets on the amplifiers.

First of all, some clarifications/reminders. The amplifiers are always connected to the TX VFO in use. If WSJT-X Settings – Radio – Split is set to “None”, VFO A is used for transmission as well as reception. VFO B is not in use. The same applies to “Fake it”, only VFO A is in use. In “Fake it”, the “split” effect is achieved by VFO A changing frequencies between the TX and RX sequences, if the audio frequency is outside the 1500-2000 Hz sweetspot. Only when Split is set to “Rig” does WSJT-X apply both VFOs, and then VFO A is used for RX only, whilst VFO B is the one used for transmission and thereby is the one to activate the amplifier.

WSJT-X 2.3.1 – All OK

We first tried with WSJT-X 2.3.1. No matter which Split setting we used, the radio and the PA immediately followed all band changes in WSJT-X. This has been our smooth experience for years, until version 2.4.0.

WSJT-X 2.4.0 – Radio VFO B changes band, the PA does not

We then tried with WSJT-X 2.4.0 (the current GA). With Split set to “None” or “Fake it”, VFO A followed the band changes in WSJT-X and the amplifier followed the VFO A. VFO B stayed in the previous band, which was as expected, as for “None” or “Fake it” VFO B is simply not in use.

With Split set to “Rig”, VFO A and VFO B followed the band change in WSJT-X, whilst the amplifier did not and stayed in the previous band, as previously described. As the amplifier follows the TX VFO, i.e. VFO B, it was to be expected that the amplifier changed bands when VFO B changed bands. The question here is: Why has VFO B stopped instructing the amplifier to change bands, or why has the amplifier stopped taking orders from VFO B? 

WSJT-X 2.5.0-rc5 – Neither the Radio VFO B nor the PA changes band

Finally, we tried WSJT-X 2.5.0-rc5, the release candidate at hand when the tests were conducted.

With Split set to “None” or “Fake it”, VFO A changed bands, but the amplifier did not follow. VFO B was unaffected, as expected, as it is not in use in “None” or “Fake it”.

With Split set to “Rig”, VFO A followed the band changes in WSJT-X, whilst VFO B as well as the amplifier stayed in the previous band. As the amplifier follows the TX VFO, i.e. VFO B, it was to be expected that the amplifier did not change when VFO B did not change.

The question now is: Why has WSJT-X stopped instructing VFO B to change bands? This time the PA can not be the one to blame (yet), as the PA does exactly as instructed by VFO B: Stay in the previous band.

CI-V Transceive and CI-V Output (for ANT) ON or OFF have no influence

All the exercises above were systematically conducted with all combinations of the radio’s SET – OTHERS – “CI-V Transceive” and SET – OTHERS – “CI-V Output (to ANT)” toggled between ON and OFF. These two settings made no difference in the results described above.

That it works with “CI-V Transceive” ON as well as OFF seems to be in line with the WSJT-X User Guide, section 16. Frequently Asked Questions, #4:

I occasionally get Rig Control Errors if I adjust my Icom rig’s VFO. What’s wrong?

By default, most Icom transceivers have *CI-V Transceive Mode" enabled. This will cause unsolicited CAT traffic from the rig that disrupts CAT control by a PC. Disable this option in the rig’s menu.

Expert 1.3K-FA and Expert 1K-FA give the same results

We have made the above tests on both our old Expert 1K-FA and our new Expert 1.3K-FA. The results are identical.

TX Audio frequency makes no difference

Trying several TX audio frequencies below, above and in the 1500-2000 Hz audio sweetspot made no difference.

N1MM Logger+ works smoothly with version 2.4.0

In the WW-DIGI Contest, I used the club station with WSJT-X 2.4.0 with N1MM Logger+ running the IC-7600 and the Expert 1.3K-FA. Everything worked smoothly, just like in version 2.3.1. As soon as I tried to operate version 2.4.0 standalone with no other changes made anywhere, the band change issue returned.

Is there any clue in the fact that version 2.4.0 does not change PA bands when operated standalone, whilst it works just fine when controlled by N1MM Logger+?


In version 2.3.1, everything works smoothly.

In version 2.4.0, VFO-B changes bands as instructed by WSJT-X, but the amplifier does not change bands. Version 2.4.0 works flawlessly when WSJT-X operates under N1MM Logger+.

In version 2.5.0-rc5, VFO B does not even change and then obviously not the amplifier.

The WSJT-X version number is the only identifiable variable that has an influence on the PA band changes.

That is why we think that the non-working PA band changes in WSJT-X 2.4.0 (standalone) and 2.5.0-rc5 have something to do with changes in the later versions of WSJT-X and/or it’s auxiliary CAT software.

73, Frode LA6VQ

Join main@WSJTX.groups.io to automatically receive all group messages.