▁with ▁three ▁transmit ters ▁connected ▁to ▁each ▁of ▁the ▁two ▁transmit ▁anten nas . ▁Because ▁small ▁variations ▁affect ▁every ▁anten na , ▁each ▁anten na ▁will ▁have ▁a ▁slightly ▁different ▁direction al ▁pattern . ▁Each ▁anten na ▁will ▁interact ▁with ▁the ▁tower ▁and ▁other ▁nearby ▁anten nas ▁differently . ▁If ▁one ▁were ▁to ▁measure ▁received ▁signal ▁levels , ▁this ▁would ▁cause ▁a ▁variation ▁among ▁channels ▁on ▁a ▁single ▁tr unk ed ▁system . ▁Vari ations ▁in ▁signal ▁strength ▁among ▁channels ▁on ▁one ▁tr unk ed ▁system ▁can ▁also ▁be ▁caused ▁by : ▁ ▁failed ▁parts ▁in ▁the ▁combin er , ▁▁ ▁characteristics ▁of ▁the ▁design , ▁▁ ▁loose ▁connect ors , ▁▁ ▁bad ▁c ables , ▁▁ ▁mist un ed ▁filters , ▁or ; ▁▁ ▁incorrectly ▁installed ▁components . ▁ ▁Modern ▁ ▁Cross - band ▁repe aters ▁are ▁sometimes ▁a ▁part ▁of ▁government ▁tr unk ed ▁radio ▁systems . ▁If ▁one ▁community ▁is ▁on ▁a ▁tr unk ed ▁system ▁and ▁the ▁neighbor ing ▁community ▁is ▁on ▁a ▁conventional ▁system , ▁a ▁talk ▁group ▁or ▁ag ency - f le et - sub f le et ▁may ▁be ▁designated ▁to ▁communicate ▁with ▁the ▁other ▁community . ▁In ▁an ▁example ▁where ▁the ▁community ▁is ▁on ▁ 1 5 3 . 7 5 5   M Hz , ▁transm itting ▁on ▁the ▁tr unk ed ▁system ▁talk ▁group ▁would ▁repeat ▁on ▁ 1 5 3 . 7 5 5   M Hz . ▁Sign als ▁received ▁by ▁a ▁base ▁station ▁on ▁ 1 5 3 .