[Hey you] [It's Me] [Message]
When people speak over a common comms channel, they often follow the "Hey-you, it's-me" format.
Conn, Sonar, Crazy Ivan!
This line, from The Hunt for Red October, really means:
Hey Control Room, this is the Sonar Operator. The Russia Submarine is doing a Crazy Ivan Maneuver!
But it has been shortened to just the essentials.
Star Trek often used the same idea, but with a different order and the keyword "to" to give sender / receiver information.
[Riker] Riker to Picard.
[Picard] Go Ahead Number One.
Tone, Facial Expressions, and Actions
Most communication is not in the dialog - it's in the tone, facial expression, etc. that accompanies the dialog. Much of that is lost over radio, but there is still some ability to influence the message.
So if Karen is supposed to be mocking John, I might try something like this:
Karen's radio squawked to life. HQ, this is Dark Sabre, how copy? Over.
The tower operator didn't miss a beat. Dark Sabre, this is HQ, you're loud and clear.
Karen smirked as she keyed her mic. Dinky Dagger, she drawled out the words, emphasizing them. This is Mama Bear. Did you change your callsign?
She put a sugary sweet tone on the question, feigning naivete hard enough that the mockery came through even across the static of a radio link.
She didn't get to revel in her little jab very long, though.
All Stations, this is HQ Actual. The Commander's voice was hard as a cliff face. Bicker on your own time.