Mine only responds to ATC queries, which increase or
decrease in relation to distance. If yours sends replies
when out of ATC range I would suspect the unit.


At 08:54 17 July 2005, Ian wrote:
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