Batboard

I've noticed that my AS3(UHF 460Mhz region) has much better receive sensitivity with the PS Speaker Mic, than it does with the same(or different, ie have tried helical and short) antenna mounted directly on the top of thr radio. This occurs even when I duplicate the exact placement of the antenna in space, so we are not looking at capacitance effects or positioning phenomena. (Don't have proper test equipment to measure quantitatively, but effect is very significant) Any ideas? Thank you.

Well, I wouldn't say sensitivity, but it's possible the cord from the radio to the mike acts as an antenna, thereby the radio seeing a bigger antenna than the one on the sp/mike.