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cannons makes a strong point, just as does damage outside a circle around an isolated cannon. Pagers HAIL CANNON HANDBOOK The pager is started by dialling one number, \~hich rings briefly and then tells you your call has been accepted. The stop command is given by a second number, in the same \.-Jay. One of the problems \.-Jith the lack of predictability of hailstorms is that you can't always be within running distance of the hail cannon, and also some-one on an adjacent property may be better __-able_to..-see-.an.___ _ - -_ _ _ _ _ ____ --- approaching storm. Using radio pagers \.-Jhich operate via the Telecom pager net\.-Jork provides a reliable method of remote control, so we are able to ensure the cannon can be started from anywhere in the country. Natu~ally we suggest you keep the pager code between yourself and those you can trust! Like all modern gadgets, there are some Ilmits on what can be achieved, essentially a line of sight usually needs to exist between the paging transmitter site and the pager mounted on the hail cannon controller, although this rule can be bent - more so when you are near the pager transmitter. Pager signals penetrate most typ~S of buildlngs, even corrugated iron usually has little effect. Several calls can be made to start the unit, they ~ill not interfere with each other. Of course a single stop call will halt the firing. You will probably keep that number private as well. Startup volume Because the sudden firing of a canoon without warning would startle anyone within at least 200 metres, we decided to start the firing quietly and build up to full volume over about one and one half minutes. This ~as intended as a reasonable compromise bet~een the need fOr a warning, and the need to get the unit quickly into operation. Reliability We needed to be sure the unit would operate when required over a long perlod of time, and there should be the minimum danger of damage to the unit or its surroundings if something sKould go wrong. The most important part of such reliability is the choice of good MIKE EGGERS LTD. Nelson, New Zealand .';,":':9...<:;:::'~ quality parts, assembled into a unit with inherently safe design practices. while nothing man made can be totally reliable this unit incorporates the best practices available in the construction of the cannon firing chamber, the gas injection system, and the controlling computer system. The dual fuel supply and the dual firing provide ..the. best c::n'lnn pl,l <::e...,_and_ __ also provides duplication of the -least reliable parts. The failure of one gas valve or ignition system will reduce the output level of the unit, but it will remain highly effectlve. Sound - W.~~O~~ING The level of sound produced by the cannon is very high. and it is not acceptable to spend more than 8 hours closer than 200 metres to it without hearing protection. As you approach the cannon, the sound level increases rapldly, and adJacent to the cannon, the sound level is such that Grade 5 earmuffs (the highest level usually only available from a safety equipment supplier) should be worn. The level of sound at metres JS 156.8dBa as measured by O.S.H. Page 4