[MRCA] R105D / R105M

[wf2u at starband.net]

Indeed the R-105 is useless for legal i.e. Amateur operation due to it's
frequency range.
As to the substitute for the wet cell batteries originally used, the way
to easily power up the radios requiring +/- 2.8V is from a 5 V power
supply, through a simple an artificial center tap consisting of a couple
of diodes and resistors. The circuit is not tricky at all and works great
with nothing to adjust.
I can either send the circuit or point to a web site where the circuit is
presented (I'm at work now so I can do it later when I get home).
I use this setup to power up my Russian R-104M HF transceiver (all tubes,
20 W output)  and the same circuit will work as well with low power sets.

73, Meir WF2U
Landrum, SC

(Russian/Eastern Block equipment: RBM, R-104M, R-130M, R-250M, R-311,
R-250M, R-326, R-350M, R-807/US-9 (the Russian ART-13/BC-348), US-8, R-4,
RFT 1340.21, SEG-15D)


> I may be the guilty party being that for the past couple years I have
> been operating a R-107 for the "cold war net" at Dayton and also for the
> 51.0 net at MRCA along with a number of other Russian radios. Myself
> have seen the R-105 series before but have not owned one due to the
> problem that radio only covers 36 to 46 Mc so not very useful in the ham
> bands. The whole fammily of the R-105/108 and 109 together cover 21.5 to
> 46.1 Mc so perhaps the R-108 and 109 can be used on ten meters for FM,
> but the 105 is outside just about anything that can be legally used. All
> the radios use two 2.5 volt wet cell Ni Cad batteries and their is a
> circuit for adapting them to use a five volt power source but it can be
> tricky especially with the D being the older series with the big tubes,
> don't know because I have not done it myself not owning any of that
> family but would think the D series draws more current then the newer M
> series with the peanut tubes and solid state inverter, although I have
> found that in the R-311 the Russian designed vibrator power supply is
> way more efficient then anything the west produced at that time. A good
> web site to look at would be: HTTP://home.online.no/~perchri/index.htm
> I also posted some pictures of a couple Russian radios I have on my web
> site at: www.ka3ekh.net
>
> Ray Fantini KA3EKH
>
>