i have a dual conversion receiver, and a single conv. tx module, i cant get them to communicate ... is there a compatability issue?

There's no such thing as a single or dual conversion transmitter module. Conversion (or heterodyning) is purely a factor of how the receiver handles the incoming signal to reduce its frequency to a useable number.

They must be on the same channel, and same shift (jr and futaba are opposite shift)

they both must also be fm or pcm some tx will put out either you just set it to one or the other( i got a new pcm receiver same brand and channel as my tx and it wouldnt communicate till i changed my tx to output pcm)

PCM and PPM both use FM, just so you know.

they may both use fm but if you have your tx set on ppm and have an pcm receiver it will not work

sorry for the double post