Moosie

Is the service center in New Zealand; in any case is it an approved service center or a Hitec facility?

You HAVE a range problem if your experiencing problems at 100' with the antenna extended.

Did you purchase this set new? Has it been retuned, crystals changed out, RX's originally manufactured for the frequency and or band used in your world. Do the RX's you have tried other than Hitec products require retuning with crystals change outs? Are these all Dual Conversion RX's with the appropriate crystals? Are you changing out the TX module when changing out frequencies? Are you using a Spectra module?