[Milsurplus] Nihm Battery pack for PRC-25

[John Watkins via Milsurplus]

 It has always been a bit of a pain to build a battery pack for the PRC-25, easy to do, but.  2 ways to do it, put in 2 extra batteries for the 2DF4 filament (2.45 Volts at 345 mills). You did use that Nicrome wire in for the filament if using alkaline batteries (1.5V), right. Or we tap off of the last or first 2 batteries in the 12V pack for the filament.  NIMH batteries are 1.2 volt cells, so you could leave off the Nicrome current limit wire. I found that you can use an LM 2937 3 terminal regulator and just tap off the complete 12V battery.  Easy to use and lots of room for a heat sink (doesn't have to be a big one).  I put a 0.1 Uf on the input and a 47 Uf on the output.  I did put in a used 20 watt 10 ohm resistor.  Didn't really need it, but it does drop 3.45 volts off the input of the LM 2937.  Makes it easy to recharge the NIMH or NICAD pack.  Just tried it on my old RCA PRC-25 and works fine.
John  WD5ENU