Updated Opinions of DC30?

I have been using 5 x DC 30s for about a year hunting here in New Zealand .We don't only have huge hills here but mountains with snow on top near to where we hunt .The radio signal is by far the weak link with this gear ,but we replace the rubber aerial on the reciever with a cable aerial that doubles the range over the factory one ( not as good as the long range aerial but you don't have to carry that around when out in the field)and replace the aerials on the collars with cable aerials that gives another up 30% range .We also srink rap the collars for add protection.