[R-390] R-390A's, Sandstate sets and Desert Storm static damage

[rbethman@comcast.net]

Phil - Read comments made throughout.

Bob
----- Original Message ----- From: "Philip Atchley"
Subject: [R-390] R-390A's, Sandstate sets and Desert Storm static damage


| Hello all.
| You know, I keep reading about how "Uncles" modern radios used in Desert
| Storm suffered so much static damage from windblown sand etc that he
rushed
| in R-390A's, KWM-2's etc.
|
| I have seen large static buildup on wire antennas, so I know it's real.
| When I was in the Barracks in Spain (mountaintop site) I had a longwire
| about 120' long or so stretched between two wings of the building.  On
more
| than one occasion I saw arcs over an inch long jump from the disconnected
| antenna to the radio case (tube radio 8^).  And this on what seemed to be
| clear but windy days!
|
| But, what doesn't make sense to me about these stories are two things.
|
| 1. It seems to me that on a receiver (or even a transmitter) it wouldn't
be
| all that difficult to couple the antenna to the set through a Balun or
Unun
| so that the receiver ALWAYS has a DC path between the antenna and it's
| ground thus making sure that a high DC couldn't be coupled into the radio
| and likewise on the antenna side a DC path to ground to prevent any
Voltage
| buildup.  Where you get into trouble is when there is no DC path to drain
| the static off.  Any Radio man worth his salt ought to know this.

The FIRST thing to consider - Uncle is MOBILE.  The Hummers, Jeeps, 2 1/2
tons, Tanks and the rest are "moving".  This doesn't allow for a "ground".

They are using vehicle mounted whips, not dipoles or the like.

The few times they set up a command post, they are still using whips (for
the most part) to maintain polarity with the masses.  They may get lucky and
drive a gound rod or two - IN DESERT SAND.  Essentially NO GROUND.

The only thing I can attest to - from spending time out "there", the static
buildup is horrendous!  The sand provides NO MEANS of a ground.

Tactical necessity doesn't allow for digging deep trenches, heat issues
preclude using water to soak grounds.  The people NEED IT MORE.

Sliding an R-390A out of the case and blowing compressed air through it is
not a problem.  Keeps them functional.

What do you do with a finicky Harris - Watkins Johnson, or whatever?  They
can't take the static, can't take the heat!, and die faster than you can
replace them.

That's why Uncle keeps R-390As in a warehouse in Northern Calif, all
refurbed, and ready to go.  "Spares included"!
|
| 2.  In desert conditions like Desert Storm it "seems" to me that dirt and
| grit getting into the gears (and slug tuned coils) of a R-390A or tuning
| mechanism/tuning slugs of a KWM-2 would prove far more troublesome to
| reliability!  (Ask those who bought "Blue stripers" and had to clean em).
|

Bob - N0DGN
U.S. Army Spec Ops Retired
SFC