Battery low charge state conditions, combined with voltage drops in wiring, can cause reduction in output power, transmit signal distortionor even total shutdown in many radios. One solution to this problem is to build a switch-mode power supply (SMPS) to maintain the dc input voltage. An SMPS can offer boosted power levels and allow longer operating times from a given battery.
To find more information, see the Wikipedia page on Switched Mode Power Supplies Click HERE
Repeater Builder has an article on the N8XJK Battery Booster Click HERE
Zip file with updates to the N8XJK Batter Booster Click HERE for zip file
Far Circuits has a partial kit for the N8XJK, QST Nov 2004. Click Here for Far Circuits PDF Info and HERE to order a board.
TGElectronics has a commercial version of the N8XJK power booster Click HERE
N0QE runs a test of a TGElectronics power booster CLICK HERE
Berks County provides some information on battery boosters Click HERE