As has been said before "RF gotta go somewhere".   Your buddy got lucky!

My experience is that rigs are much more robust than popular myth seems to claim.
I've transmitted any number of times without an antenna connected, or with shorted
or open coax, over the years, and haven't blown a final (tube or transistor) from it.

But that doesn't mean it is a good habit to develop!


Most modern solid state rigs have protection circuits built in.  With tube rigs the plate
current meter would show that something is wrong when you go to dip it.

It seems that the most common cause of final failure is overheating.  I've only blown
2 finals in 40+ years as a ham:  one was a 2m FM rig under the seat of my car where
the heater vent blew on the heatsink, and the other was a QRP rig when I tried to see
how much output power I could get from a TO-18 transistor.  (OK, perhaps drawing
100mA through a 50mA transistor had something to do with it, too.)

But even when a disconnected antenna causes high dissipation in the final, that won't
cause damage until it continues long enough for the temperature to rise.  With a small
transistor that can happen pretty quickly, but in most cases it is the excessive dissipation
over an extended time that causes problems.

This doesn't mean that it is good practice, of course, but generally brief lapses of attention
such as that don't cause permanent damage as long as they don't go on for too long.

I switch my rigs into a dummy load during a storm.

Advise him to make a card to place on the top of the tranceiver ANTENNA NOT CONNECTED

Mel G0GQK

Let me give you some better advice that I was given and always follow.

WHEN YOU DISCONNECT THE ANTENNA ALWAYS DISCONNECT THE MIC !

It's that simple, when I see my Mic disconnected I know something is not in order so it jogs my memory. I do it when the Antenna is disconnected or if something is wrong with some piece of equipment in the Tx line.