[aprssig] APRS Radiation sensor

Bob Bruninga bruninga at usna.edu
Wed Mar 23 17:52:59 EDT 2011

Of course, every geiger counter kit is now sold out.

But is there a cheap alternative?

All we need is a large set of parallel plates and a means to detect a
passing particle causing a momentary change in conduction.  Crazy thought
here, but would a large capacitor work?  It has the large surface area and
ionizing radiation would surely cause a momentary pulse..

OH.. shucks.  But then what you have is the other 99.9999999% of the
parallel plates acting like a HUGE filter capacitor ACROSS the output...
thus completely swamping the pulse.  Sheesh... nevermind.

The Geiger tube has very low capacitance.  Hence very easy to detect.

Maybe just for grins one could try the physically largest (High voltage) and
lowest value capacitor they have in their junkbox, biased, and hooked to a
high gain audio amp?
Bob, Wb4APR

-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Tapio Sokura
Sent: Wednesday, March 23, 2011 5:22 PM
To: aprssig at tapr.org
Subject: Re: [aprssig] APRS Radiation sensor

On 03/22/2011 10:31 PM, Pentti Gronlund wrote:
> Bob Bruninga writes:
>> How about this for Radiation Telemetry:
>> Using Tapio's idea (below) of 2 digits of precision and one digit of

> Actually this idea was mine. Tapio did most of the work in putting
> it all together in readable form.

Benjamin is right, it was his idea on IRC and I basically just wrote it
out. So I should've used the wording "We are suggesting..." and
enumerated the "we" part.  Anyway neither of us is wants any royalties
on it, so go ahead and use it if you like :-)


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