i use http://www.johnsonstelemetry.com/
for their collars and i use a wildlife box http://www.wildlifematerials.com/
I use these on bear hounds and iam not sure of what type of application your looking but these work exceptionally well for me.
there are others that you may find easily on most search engines, magnum telemetry, quicktrack,and, wick outdoor works carries a line of tracking collars as well.Hope that helps you out!
Folks,This is gonna be a gross read - but it is worth it...Tony makes and uses this to great success... just look at the photo album I have posted here to see how well it works... let me say this, also - all of Tony's photos come from 2 small 250 acre tracts... you do not have to have 5000 acres to make this work.First - the gross part.. the recipe:In a gallon container, combine 2 finely pureed apples (complete apple), a cup of plain non scented ammonia and fill the container the rest of the...