[MRCA] [MMRCG] Soviet R-107

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so I've been building a lot of batteries lately and I've learned that designing a system that is set for the nominal voltage can be difficult to do.    so you have to figure out the electronics are designed to handle the peak voltage of any battery system.   so is everything is set up normally a 2.5 volt battery system should probably should be capable of having a peak charge voltage of 3.4 volt..   I'm assuming the Russians would have designed their equipment to at least handle the peak voltages of a charged battery just a thought.   it's my uneducated but someone experienced opinion.....lol 
 
 
 
 
 
 
 
 walt 
 
 
 
 
 
 
 
 


 
 
 Years ago I was running a Soviet R-107 transceiver at a lot of events on 51.0 and at that time was still using the original Soviet – Russian KNP-20 Nickel Iron or Cadmium batteries  but they were always a issue at best. They produced gobs
 of power at 2.5 volts each but were filled with water and Potassium Hydroxide or Lithium Hydroxide or some combination of such and would leak when charging, leak when sitting around and what they leaked was some caustic substance that attacked connectors,
 wire or anything else that was around them. The battery compartment in the radio is lined with a epoxy or some form of paint and sealed from the radio just for that reason.
 
 So here we are years later and I want to start using that radio again at events. But the batteries that were stored separate are just too scary to consider at this point.  The radio draws a couple hundred mills in receiver and around two
 amps in transmit. Although the radio uses a bunch of sub miniature tubes it has a solid state power supply for providing the 1.35 for filaments, 60 volts and high voltage of 160 volts with the added benefit of a regulated filament supply. 
 All of this was designed to work on 5 volts from two sets of KNP-20 cells, the center tap of the two batteries is grounded so the radio received +2.5 and -2.5 although the inverter in the power supply did not use the center tap source from
 the batteries. What dose use that source is a hand full of dual coil relays that do the transition between receiver and transmit, remote control if the phone is connected and a couple other functions. Each of these dual coil relays are set up for operation
 on 2.5 Vdc. 
 My new plan is to use a modern 6 volt 7Ah SLA cell that will fit into the battery compartment along with a diode and resistor network that provide an artificial center tap and been playing around with that but the question now is will there
 be an issue running all the relays twenty percent over the voltage they were using? It’s now three volts on each of the two and a half volt buses, but oddly the voltmeter on the radio that lets you monitor the two point five volt buses along with the sixty
 volt bus shows everything in the green. 
 What’s the consensus about operating things at 120% ? They do have a regulator built into the filament bus so not worried about that  and feel that the one thing that the old soviet system did well was over design components and this may
 not be an issue for the relays in the radio. 
 What do you think? 
   
 Ray F/KA3EKH  
 
 




 
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