Graupner MX-12 compatibility
 

Hi there,
I have a Graupner MX-12 35Mhz radio which works fine with the R700 Graupner receiver it came with.
I recently bought 2 HFD-08RO dual conversion receivers with hitec dual conversion crystals (channel 64 same as the MX12). They both have a very short range (about 7-10m with the antenna collapsed). I tried different positions for the antenna as well as removing the servos/esc plug so I don't think it is an interferrence problem.
Is there any compatibility issue with the Graupner/JR radio? I asked the local dealer and they say it shoud be working fine.
Thanx