VarAC with SmartSDR

I have been away from ham radio for about a year so I appologize if this issue has been discussed and resolved.

Back a year ago, I used VarAC with the VARA modem connected to my Flex 6300 running an earlier version of SmartSDR and everthing worked beatutifully.

As part of recently restarting my digital ham activities, I have upgraded SmartSDR to 3.7.4, VARA to 4.8.7, and VarAC to 9.1.0 all of which are the lastest versions. OS is Windows 11 with lastest updates.

I am running CAT via TCP with no problem selecting frequency or triggering PTT. I am using DAX for both receive and transmit audio and the receive path works perfectly. However, there is a glitch in the DAX audio transmit path.

Transmit audio level is set for proper ALC. In fact, transmit sort of works. However, there are sometimes dropouts during transmission which can be seen on the SmartSDR RF waterfall and on received VARA waterfall from a separate Icom IC-7300 based setup. Transmitted data is received correctly about half of the time. When I send a VarAC CQ (2 messages), sometimes one is transmitted and sometimes none.

With so many moving parts, I wanted to isolate the issue. I connected the digital audio output stream from VARA to a hardware sound card and then phyically connected the analog output of the soundcard to the 6300 MIC input. That works perfectly. However, this physical solution can't be operated remotely which is one of my objectives.

One other piece of information. When I do a "VARA Tune" which sends a single 1500 Hz tone instead of multiple tones, I don't see the dropout.

I have reinstalled SmartSDR 3.7.4. I have reinstalled VARA. I have tried this setup on two desktops and one laptop computer with consisted results. All computers are running Windows 11.

Any help or insight would be appreicated.

Larry

W6LVP