Aghh, good old wombats!

I'd suggest that any adjustable gain isnt going to help much. I'd
concentrate more on your statement "This system was used previously with
no problems". Do you have a breakage somewhere? Are the troublesome
systems on one receiver? (if you have more than one) Are you sharing the
frequency with someone else and getting interference? Are there any
other sources of interference that may be the problem?

I suggest that horizontally is the best orientation as the antennas on
the animals are probably also horizontal.

In my situation I'd also tune the equipment for best output just in case
the attached wombats have damaged them. You *could* put a preamp on the
receiver but I think that will invite more problems than provide a
viable solution

If you have a scanning receiver have a listen separately for each collar
signal. If they are all there suspect the base anytenna/receiver as
being faulty. You may also hear interference.

Hope this helps

Cheers Bob VK2YQA

Krys wrote:
I have a telemetry system set up so I can have radio collars on
animals (wombats) which transmits to a directional Yagi 3 antenna and
through to a TR-5 Telonics receiver. I am getting activity data now
directional data.