I have a GMC-320+ but I don't think I can use it with Radiation Network Software which seems to require only pulses from the output port of the counter. What older model GQ's have only pulses on the output port?
I think it does need analog pulse, so I listened at the output jack and there are pulses in the headphones that correspond to the counts. The 320+ will probably work. Have you used the GQ software to map your location data on their map?