Becker 4404-1 Transponder Behaviour

[Ian]

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

[Gary Evans]

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
>
>

[bumper]

Transponders will also reply to TCAS interrogations, even when out of ATC
radar range. Putting the glider in a metal hangar or glider trailer should
adequately "shield" the transponder. If it replies then, I'd think you have
a problem. Easy approach would be to just fly with it for awhile and see if
it returns to the behavior you expect (g).

bumper
"Gary Evans" > wrote in message
...
> 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
>>
>>
>
>
>