Dear Joan,

Following the most interesting lecture given at the last AGM by Dave Morton about his experience of using a hand-held GPS for navigating his Wayfarer from Scotland to Ulster and the Isle-of-Man, there was a discussion about the problems of battery life of such portable GPS units.

One of the solutions proposed was to consider the hand-cranked power supply of Trevor Baylis’s now famous ‘clockwork radio’. I telephoned Trevor who evinced some interest but he is more enthused with producing a complete clockwork GPS, rather than supply just the power unit. There may me some technical justification for this to ensure that the voltage wave-form characteristics match the GPS requirements.

I am more interested in a standard power supply for one of the widely available GPS units. I have recently found a well-made, waterproof, battery power pack, produced by a small company at Itchenor, made for electronic devices such as depth sounders in day racing keelboats, portable VHF and GPS.

The address is: Hove To, The Street, Itchenor, Chichester, West Sussex PO20 7AH tel: 01243 512503.

The price is £35 — please mention the DCA. Colin Newnes