I have the Terra 760 Com stacked on top of the Terra IFF, and after sending them to Trimble (now out of the business), they have been working very well. I noticed recently a little static when receiving com transmissions from other distant aircraft. I initially thought the problem was the other transmissions, but then noticed the static goes away when I turned the IFF off. I further trouble-shot it by checking without mode C, same result. The problem does not seem to be associated with the interrogate/transmit light on the IFF, but occurs whenever the IFF is on. I tried putting EMI suppressors (magnetic donuts) on the ground leads from the two units, and there might be slight improvement, but it is still there. I don't think it is associated with the antennas, since it doesn't seem to be associated with IFF interrogation. I also played with squelch, in the automatic mode and at various manual positions, and that does not seem to affect it, although the static does sound somewhat like a high squelch.
I am about out of ideas, any inputs appreciated.
I am about out of ideas, any inputs appreciated.
