Just wondered if the modulation for the Spectra and DCX receiver were PCM or PPM or something else, help?

PPM (FM)

Another question... the Hitec Spectra module has a PCM/PPM frequency capability on it. Is there any way to get the PCM frequency with the Aggressor CRX? I checked in the CRX manual and couldn't find it mentioned anywhere? I have a Futaba 1024 PCM reciever and can't get my CRX radio to work with it!

Sorry, CRX is FM only.

I thought the PCM was still FM, is it not? My friend has a 3PK that he runs a spectra from also (FM) but his radio has the ability of changing modulation from PPM to PCM and HRS, aren't all those still under FM? The crystals in the recievers don't need to change between PPM and PCM and they are FM 75mhz crystals!

PCM is in part of the encoding of the signal.....
So yes, you are correct.

I should have stated it differently.

However, the CRX does not support PCM, only PPM.

Thanks for your help!