Transponder Check

Cadstat · #1 02-22-2011, 02:05 PM

I bought a used RV but I never see a 'blink' on the transponder light. I push the test and I think I'm susposed to see the light come on but don't. What's the next step? Fly to a towered airport and ask if they see me? Or just pull the radio and send to the shop? I've never had one go bad.

Mike S · #2 02-22-2011, 02:23 PM

What brand Xpndr??

Is this problem on the ground, or in flight??

My Garmin goes to sleep when on the ground.

Ask ATC if they are getting a signal when you go flying next time.

allbee · #3 02-22-2011, 02:53 PM

I have the Garmin and there is suppose to be a blip on my screen when the radar hits. Well I don't see mine either. I asked if my transponder was working one day and yup, told me my current altitude and everything. So I guess that doesn't matter.

Lycosaurus · #4 02-22-2011, 04:57 PM

I had the same concern with my -327 about 2 years ago and started a thread regarding this. I answered my own question by calling Garmin tech support. Please see the following thread..... should answer your question:
http://www.vansairforce.com/communit...nsponder+reply

Here's a summary of Garmin's comment:
Please be aware that the reply annunciation is a software function – not a hardware response to an interrogation.

The reply indicator light has an approximate “pulse repetition frequency (PRF)” associated with it. If the unit is not providing 200 replies in a second, the icon won’t appear (the unit isn’t “busy” replying). The GTX 327 may still reply to ATC without the indicator turning on. If the shop would like observe the GTX 327 not displaying the reply indicator so they can envision how it is working in the air, they can lower the PRF on their test set if it has the option. As the PRF is lowered, they should observe that the reply indicator stops displaying."