Newbie Question

[VK4ADC]

Im trying to get rid of the Uniden UHF. Its pretty poor, receive range is less than 3km though the transmit is somewhat longer. I have a 1 watt handheld UHF that gets 5km easily, my 5 watt vehicle radio is next to useless. In a vehicle convoy the Uniden wont RX/TX to vehicles I can see around me. Its been back to the dealer twice and they say there is nothing wrong with either the radio or the antenna.

Ive never been a fan of UHF, always used VHF or HF in the military. I always thought our VHF radios were bad but UHF is like using two cans on a piece of string.

When I was at an outdoor show at the Gold Coast Turf Club last year I was talking with a guy from a amateur radio network about HF. Whilst chatting he showed his setup. One radio was his HF but the other was a VHF/UHF combo. He was monitoring two channels at the same time and was able to switch between them. Whilst we were talking we were listening to vehicles as well as Southport Coast Guard.

While it may seem strange to ask, what type of antenna are you using on the 4X4 ? Model number ?
Different antennas have different lobe angles and high gain antennas designed for accessing repeaters on high hills/mountains may have a high lobe angle while you actually need a more horizontal lobe angle for reasonable distance vehicle-vehicle comms. These are generally have a lower published gain figure and are a straight (or variant of a) quarter wavelength whip.

There is nothing to stop you putting VHF marine frequencies or UHF CB frequencies into an amateur transceiver if the receiver will cover those frequencies but it can only be used on receive for them. The amateur equipment can't be used to transmit on those frequencies as it isn't Type Approved for the other services - in fact, it generally isn't Type Approved at all.

UHF is even more line-of-sight than VHF hence the more obvious distance limitation. VHF has always been described as extended line-of-sight and handles obstructions such as trees, foliage, small hills etc better as there is less signal attenuation from those at VHF than at UHF.

Hope that helps..

Doug VK4ADC