Military-Vehicles: Re: [MV] Radioactive

Re: [MV] Radioactive

Douglas Greville (
Wed, 29 Oct 1997 19:05:24 +1030

CHAZ wrote:

> Hi list , I borrowed a Geiger counter tonight to see whether
> my No.19 radio set was as radioactive as I'd been told . It's not
> radioactive at all.

I disagree, as I have checked No.19 radio sets and they are
radioactive (using a Geiger Counter calibrated on Cesium 137).
The part on the No.19 set that gives a high count is the flip-flop
channel indicator (basically a yellow/white dot that appears behind
a hole when you switch between the current and qued channel.

> Background radiation is 31.

Just what was this Geiger counter you borrowed calibrated on anyway?
If it is a geological type then I think you are using the wrong type
as far as the readings go, but it would still give you some sort of
comparison between subjects. Either that or you had better check that
you arn't living on top of an Uranium deposit.

This seems way to high. Background should be more like 9 counts at
sea level to 14 counts at say 1000' above sea level
per second averaged out of readings taken over several days. The
difference in counts varies depending on your height above sea level
and solar activity.

> Whats a safe level for things like instruments?

I wish I knew or could find somebody that does. Every time you get
information on radiation they talk in different measurement units
to the last source. I know it is a very complicated subject but I do
have a sneaking suspicion that the so called experts are only too
happy to keep it that way.

> Should I look for a non luminous speedo and drop the clock in a deep
> hole somewhere or what?

I did and replaced the speedo in my Greyhound with a modern repro which
looks fine. I have yet to get the 12v replacements for the fuel
guage and ammeter to give sensible readings.
This was because in the Greyhound your hands are within
2" of the instruments and I did not want to be exposed to that sort
of level of radiation. In other vehicles eg., Jeeps, your body parts
are much further away from the instruments and should be getting a
far lower exposure.

Radiation falls off in intensity from the source following the
"inverse square rule" (high school science lessons!). So as an example
you get 1/4 of the dosage at 4' than you would at 2'.

To dispose of the speedo you should take it to your
(lets see, in America, I think EPA?) Government Health Office or
Hospital. Failing that have a look on the
back of a Smoke Detector in a Supermarket and it should tell you how to
hand one in for safe disposal - same difference except your garden
variety smoke detector shouldn't get even a click out of your Geiger
counter, they are so low.

You may be interested to know that when I put a 1" thick lead shield
over my original speedo and then hold the Geiger counter about 1" away
it goes off-scale on the medium setting! This is scary as far as I am
concerned because it indicates "hard" radiation rather than say alpha
which would be easily stopped by say, a piece of sheet metal.

Rough rule of thumb: Any instrument with off white or vaguely yellow
markings is likely to be radioactive. Any instrument in service before
America = Mid 1960's
England = Late 1950's
is suspect if the markings are this colour.

I kept my speedo to show people who because they have never encountered
radioactivity won't believe that the instruments were produced this
way. The Geiger counter quickly changes that perception!

> Chaz ( probably worried about nothing )

The $64 question. I would very much like to know too?

Caveat: I am not an expert and am not qualified, if you have doubts
try and find someone who is qualified and has certified equipement
to carry out checks for you. This email is for discussion and as a
warning that there may be a problem.


                        Armoured Vehicles
      _/_(_o_)_\_                              ____
    _/|___|_|___|\_                           /____\
   /  [___] [___]  \     Douglas Greville   _/[o]___\_
  /\_ [o]     [o] _/\    Broken Hill     __/=_|____|_=\__
  |w||___________||w|    N.S.W.         /__\__________/__\
  |w|\u         u/|w|    Australia      |w| \        / |w|      
  |w| \_________/ |w|                   |w|$ \______/ $|w|
  [w]             [w]                   [w]            [w]
          M8                                  Ferret

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