Battery Backup for the Lost Plane Locators


You can fit your locator with its own battery so that if the regular flight battery fails or is ejected in a hard landing, the plane locator alarm will still sound.Connect only signal and negative leads to your receiver socket, and connect the second battery positive to positive circuit lead and negative to negative circuit lead. You will need to put some kind of switch in series with the second battery to keep it from running the alarm when you are not flying. Make sure you secure your backup battery to the locator device with tape or shrink wrap so that they will not get separated in a crash.



For the Locator I and Locator II, you can use a regular square 9V transistor radio battery.The alarm will be really loud, and the battery will last for a very long time though the battery is a bit hefty.Radioshack sells the 9V battery connectors (part 270-324) if you cannot scavenge one from one of your kidís old toys.If you use a 9 volt battery, be VERY sure that you do not connect it directly to your receiver, or you will release the magic blue smoke from your receiver.


For the Slope Shepherd, the Maxim chip used in this device has a maximum rating of 7 volts, and you must either step down the voltage with some sort of regulator (to use a 9 volt battery) or use a 6 volt battery.Frankly, I prefer the smaller 6 volt battieries anyway, and it is no problem to solder a couple leads onto the ends of these batteries.Use some fine grit sand paper to scrub off the anti-corrosive coatinga spot on the ends of the battery, scrub on a little solder in the spot with a hot iron, then press a tinned wire onto the patch of solder with the iron.Radioshack sells a 5 volt regulator LM7805 part 276-1770 for about $3 if you insist on using a 9V battery with the Slope Shepherd.


Here are some part numbers for small (1/2 AA size) 6 volt batteries that you can get at your local drug store, supermarket, or RadioShack:











PX28L or 28L











Happy hunting!

Rob Crockett