GNU Radio: Method to enable/disable Tx in running flow-graph?

[medbot]

Looking for a reliable method to control Tx for a LimeSuite Tx sink using a QT GUI Push Button.

Basically need to use the QT GUI Push Button as a PTT for the flow-graph.

The subject is described but ultimately unresolved in this thread:

Software control of TX in gnuradio

I am confused on the best method to control active transmit of the LimeSDR board when in use by gnuradio. When accessed via either the gr-limesdr or osmocom drivers, a constant carrier is always present even if the data is a null source (zeros). Use of limesdr_sink.stop() which calls LMS_StopStream(&streamId[stored.channel]) has no effect on the carrier. Gain can of course be dropped to zero but that seems to just be ignoring the central issue. Is LMS_EnableChannel() the better route or is t…

Using GNU Radio 3.8 with LimeSDR Mini.