spectrum receiver distance issues

[teambowen]

Hi Guys.
I run a spectrum wheel radio and i have a couple of receivers that have issues at distance.

To try and resolve the issues i have replaced the aireal and cases on both units with no aparrent difference.

Both receivers are fully working but one stop's working totally at say 25 metres and the second throws a wobbly at the same distance.

I have tried them in both nitro and electrics cars, which makes no difference.

Can anyone tell me where or if i can send them off to get them checked as they're not cheap.

The rx's are sr3100 model abt £50 ish each.

It is almost as if the receiver signal amplifier is not recognising the tx signal strength is reducing and thus increase the amplifier gain.

Any idea's !!!!!

Jamie.