KT76A question

[Brantel]

I picked up a yellow tagged KT76A a long while back from a South East avionics shop and just got it all wired and powered up this weekend..

My question for the many that have used one of these: Is it normal to hear the high frequency whine of the oscillator inside the unit when you power it up in a quiet environment?

I do not hear it within the headsets on or across the intercom or radio...but I do hear it in the area around the plane in my quiet garage. It is not really loud, but you can tell when the unit is on. (only in stby)

 

[Mark Burns]

Brian,
I don't know if it's normal or not, but mine does it also.

Mark

 

[jbDC9]

Mine does it too and has been working fine for 550 hrs. Must be normal I guess?

 

[Brantel]

Thanks,

Just wondered if it was normal....Most of the time in all the spam cans that I have flew that used this transponder, I have the headphones on and the engine started so one would not hear that whine. I have no way to test my purchase and the warranty runs out in a few weeks so if this is normal I will assume all is well.

 

[Randy Hooper]

Normal I guess

I had an install issue on mine not allowing the transponder to transmit.
The tech doing the check said, "I know it's working. I can hear it".

 

[Mike F]

Normal

Yes, the T-whine (transistor whine) is from the high voltage power supply and is audible in most cavity tube transponders. Transponders with a solid-state transmitter, such as the Garmin 320, 327, 330, etc., do not use a HV power supply and will not have the whine.

 

[L.Adamson]

Yes, the T-whine (transistor whine) is from the high voltage power supply and is audible in most cavity tube transponders. Transponders with a solid-state transmitter, such as the Garmin 320, 327, 330, etc., do not use a HV power supply and will not have the whine.

If I could get my engine quite enough to hear this "whine", I'd sure be happy!

L.Adamson ---- has to use ANR's