VHF radio used for forest fires

Press, Volume CXI, Issue 32802, 30 December 1971, Page 13

VHF radio used for forest fires

The New Zealand official fire season (October 1 to April 30) is new well advanced, and the threat to forests increases with high temperatures and dry conditions.

This year the Forest Service, continually seeking new ways and means to combat forest fires, has prepared even better for its role through the introduction of an improved communications system—very high frequency (VHF) mobile transmitting and receiving radio equipment.

Fire protection is the chief purpose of the VHF network, though it is very effective too for the direction of routine forest work, such as logging. Until recently the Forest Service has had to use a high frequency (HF) system which, though satisfactory during the day, is unreliable at night, mainly because of in-

terference from overseas stations. j

VHF is recognised as the most effective forest communications system, giving reliable reception 24 hours a day. Its range is limited to little more than line-of-sight distance, but within its area of coverage it gives clear, interference-free communications.

First stage The first stage of the changeover to VHF began in the Kaingaroa-Lake Taupo forests area, where about 150 new radios are being installed to replace the HF stations, and some new stations are being established. Sets are also installed in Forest Service vehicles.

Repeater stations have been set up at Rainbow Mountain, Galatea, Taupiri, and Wairango and one is under construction at Karangahape. Kaingaroa headquarters operates

through the first four of ’ these repeaters, each subdivision headquarters through 1 one local repeater, and - Turangi through Wairango' (and Karangahape when it is 1 ready). Repeater stations are! needed because two VHF; stations at forest floor level cannot communicate with each other if they are; screened by extensive intervening forest or a hill. The repeaters are sited on high ground. Though they are not much more powerful than the other stations, height gives far greater line of sight and consequently much greater range. Vehicle- sets A repeater automatically' picks up every transmission' from a station headquarters! and re-transmits it on a different frequency to all stations covered within its area. Each vehicle set is equipped to operate through any one of the forest’s repeater stations, depending on where the vehicle is; from some locations communciation is possible through two or more repeaters. Experiments are also being carried out with eight hand-held portable VHF sets, which it is hoped will replace present sets for the close man-on-foot communications needed around a forest fire. Golden Downs Forest, Nelson, now also has VHF radio? Eventually all State exotic forests will be equipped with it. Forest Service staff using the new sets report much improved communication and consequently scope for better fire protection.