[aprssig] APRS Radiation sensor

Lee Mushel herbert3 at centurytel.net
Thu Mar 24 09:42:49 EDT 2011

I found Scott's comment quite interesting.   My XYL has been a CocoRHas 
volunteer for a couple of years and had complained about where I had chosen 
to mount her rain gauge.   Of course, my only concern was "how easy is it" 
and she felt that trees were far too close.   I chose to ignore her until we 
were about to have a visit by a NOAA meteorologist who happens to share some 
other interests with me.   I decided that the easiest way to check if there 
was a problem would be to buy another rain gauge and mount it in the center 
of our 13 acre completely open field.   This was done and, much to my 
dismay, we found that there was a 20% difference in the readings!   The 
original gauge was then moved before the visit and now both readings are the 

I did note that there were geiger tubes of Russian manufacture available on 
eBay at one time.   But I suppose that they were designed to ignore anything 
short of 650 roentgens per hour.  I had my highly esteemed Precision 
Radiation Instruments Model 107B (circa 1952) modified to use ordinary C and 
D cells a few years ago.   But I noted that the new power supply apparently 
can't supply the 900 volts without some "droop" which seriously affects the 
value indicated---not only on the meter but as counts heard on the 
headphones!   I do have the original "calibration" pad but even if decay 
hasn't affected that I still know that the "Cal Adjustment" pot can be 
rotated from "avalanche" conditions to complete insensitivity.   Who knows?

But it's lots of fun to play with and it does detect stuff like old luminous 
dial watches as well.   The XYL has commented many times that we have become 
a nation of wimps.  And anyone who thinks something like a geiger counter 
should be banned is certainly in this class!


Lee  K9WRU

  - data quality on weather stations is
> kind of questionable already since no one pays much attention to 
> placement, and weather stations can at least be checked against other 
> instruments fairly easily.  A 4 or 5 digit count reading would give you 
> better resolution for tracking trends, without being misleading in the 
> units.
> Scott
> N1VG
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