[R-390] R-390A Question

[Roger Ruszkowski]

George,

Super nice you have an R390A with a tag on it.
Or is the number from one of the modules?

If you pulled the tag the receiver could be scraped as unknown junk.
If you left the tag on it was identified as an R390A with radioactive
meters that had to be removed by the junk maker and
he had to then deal with the radio active meters.

Later meter replacement we not radioactive.
A junker could just check not original meters
on the paper and let the receiver go with tag and meters.

Pull the tag pull the meters what's a junk maker to do?

There is no such thing as a Special Operations order radio.
If some one told you your receiver served in a field station
or some other special operations site you have to ask
How do they know it was actually in one of these sites.

These site likely used R390As but how is it known that
your receiver was in one of these sites.

Once upon a time there was an army and it needed some better radio's
They had some navy friends who had radios.
But the Navy guys also wanted better radios.
The air force guys were still not around.
And the marines could not conceive of a use for radios yet.
So the Army and Navy AN/ got together on the radio buy.

The good old days when things were simple and glowed in the dark.

The radios on hand were what we would call direct conversion today.

Armstrong had this idea for super heterodyne but local oscillators were
not real stable and not real linier.

Collins had this slug tuned oscillator that was linier
and he was building good direct conversion receivers that
were militarily acceptable.

The guys at Collins wrote a contract from the government to Collins.
Handed the paper to a government bureaucrat and said give this contract back to us 
to accept. The normal way government contracts are written and awarded.

This got R390's into production.
Some bureaucrat with two much time on his hands though
the R390's were to expensive and ask for a cost reduction.

Collins could not say they could build R390' for less
but they could do a R390A for less. Not exactly the same thing
so we can improve the manufacturing process and save a few bucks.
The Cost saving R390A will need a bunch of dollars up front to design.
In the end Collins was paid more for the R390A than for the R390's
That's how it works.

The receivers were so wonderful every one in the Army and the Navy 
wanted then for use in standard ship board and signal corps operations.

Some where along the line the idea popped up that we should listen to what
the other guy was talking about on his radios.

And this brings us to your Special Operations order radio question.

The military could not just let any one have the job of listening to 
the radio all day. This sounded like every one was doing nothing.
This had to be a secret job.

This listening stuff needed a bunch more radio receivers. It did not need 
transmitters. It also needed farms of antennas. But that a
different story.

So Collins got to build a bunch more less expensive R390A receivers.

A station in Africa was all R390s but most other stations were R390A
and some R390s. R390's had uses over R390As. AM voice sounded so
much better on the R390's and it still does today.

But the receivers were not built for special operations. The
receivers were the back bone for the signal corps and standard radio
traffic across all the military from WWII until sand state took over.

Special operations with no one looking at their budgets just also wanted a whole lot
of them. Then at least two receivers were used with every transmitter. 
Can you say diversity receiving.
Receivers likely out numbered 4 to 1. Receivers had value in the surplus market. You
needed your own power company to run a surplus transmitter and it likely
had more output power than you could legally use. so a lot of transmitters
were sold as real scrap.

Red light bulbs were installed in the dial lights aboard ship where night
vision was a must.

Blue light bulbs are also available from other uses but fit.

A flop down dial cover was available for the same use, and to
cover the display if you did not want casual viewers to know
what you really had playing in your head phones.

There is a micro dial add on when the receiver is used with TTY.
It let you set the BFO with a gear reduction for fine tuning and
you could dial back to the same setting time after time.

Then there were all kinds of special receivers in small quantities.

A few hundred 1950s R390As  were rebuilt with SSB in the late 1980s 1990s.

The R390 and R390A were never special operations receivers.

They were and are wonderfully receivers that also seen a lot of
use in special operations applications.

For more information goggle field station.
also Julian Creek and elephant cage
all separate subjects they will not goggle together.

Roger