hi lucka,
BER is basically no. of bits nt transmitted/total bits sent*100.Now BER has 2 values BER Sub and BER Full,Full values are calculated for 1 SACCH frame(26 Multiframe) consisting of 24 TCH TDMA frames,1SACCH frame and 1 idle frame used for measurement purposes.On the other hand Sub values are calculated by only 2 mandatory frames transmitted -1 SACCH and 1SID(SILENCE INDICATOR),
for instance if DTX DL is used (which is calculated on basis of 24 TCH blocks),so when no speech is transmitted (or we can say no Bits are transmitted during silent periods) Full values will count bits transmitted on SILENT+SPEECH so Full values will come BAD,but as Sub values only counts 1SACCH and 1SID which ar mandatory(assuming GOOD RF conditions) so they will not deteriorate, and also note that in Hoppping Specially 1/1 U MUST BE GETTING high interference and due to this BER will go down.so its should nt be a pblm ,but kindly check for MAIO,HSN,Frequencies positively and call on BCCH should also be checked for.
Rgds
yogesh_rf