Help troubleshooting glider transceiver

[JKBuck]

Hello all,
A friend and I are currently rehabilitating a Grob G102 Astir sailplane which is complete with a West German Becker radio that I think is original to the ship. The radio turns on and appears to function properly, but our transmissions are extremely weak (I'm only able to hear the transmitted message on other airband receivers with the squelch all the way off and the volume up quite a bit). Reception in the glider is also similarly very, very quiet - you can hear folks talking on frequency on the cockpit speaker, but only barely, even at maximum volume.

- The radio itself was sent to an avionics shop and apparently tested OK.
- When we hook my handheld radio to the ship antenna, everything works perfectly (transmission and reception are loud and clear via the handheld).
- The ship battery is new and putting out 12.6+ volts. We have checked the continuity of the wiring going from the battery to the radio (good) and from the radio to the speaker/microphone (also good).

What are we missing? Appreciate any input.

 

[flyingron]

What are you using for a microphone? Have you verified that microphone works well with a different transciever? Have you checked the bias voltage coming out of the radio for the microphone? WHen you say you've tried it with other airband receivers, are you getting a strong yet quiet signal (try taking the antenna of the portable radio to attenuate thing) or is it scratchy/weak as well. That will tell you if the radio/antenna is not working right, or whether it is the audio input into the modulator that's the problem.