N70 poor reception

I have just bought a used Nokia N70 on Orange, put in my 2g PAYG sim, (I
know I cannot get 3g with this sim) I find the reception very poor, keep
losing the signal in a strong area, tried setting it to GSM only with no
improvement, is it a fault with the phone or do I need a USIM 3g sim for it
to work properly?



Regards Roy