Hi

A question for those who fly with Becker 4401-1 transponders.

Normally the "Reply Indicator" triangle on the display of our transponder
flashes briefly when the unit is interrogated, but otherwise it remains
off.

Today I noticed today that it was displayed continuously. This was
when I was at low altitude and the transponder was shielded from ATC
radar by a mountain. When I climbed higher it seemed to behave more
normally, but still displayed for several seconds on some occasions.

Is this normal behavior for this unit that I have just not noticed before,
or has ours developed some kind of fault?

I can't help thinking that a continuously "Reply Indicator" implies
continues transmission, which can't be healthy.

Thanks

Ian