we been using Wildlife Materials, Inc trackers and collars here in illinois for our coonhounds for years, we're gettin too old to be roaming all the ridges and timbers trying to hear the dogs when they dissapear...me and my hunting buddy have the 10 channel one, and the trx3, a 3 channel one. each channel handles a collar of that frequency. they aint cheap, but they are good. made in carbondale, il. a range of about 6 miles max, we use em with the 16ooo hr collars with treeing switches...the treeing switch is well worth the extra money, it'll tell you if the dog is 'lookin up' or still arunnin. we've used both units a LOT and no troubles, maybe 6 yrs, probably longer. we have both types of antennas, both do the job, one is easier to use. good luck. and good hunting!