On 20/02/2015 18:00, Dave Liquorice wrote:
On Fri, 20 Feb 2015 16:41:30 +0000, Nightjar.me.uk wrote:

I've always fancied an old fashioned Geiger counter, ie one that
ticks.
Not seen any though, maybe they are not allowed in case we all
find out
the truth.

Available here, although ex-cold war and not calibrated:

http://www.anythingradioactive.com/geiger.htm#classic 700

ARGH! Toys and more toys!

Be aware that the ex-cold war meters are designed to detect and
measure the fallout from nuclear bombs, this is somewhat hotter than
natural background radiation. They might not be sensitive enough, see
text of the PDRM 82. The PDRM 82 is a bit of well made, tough as old
boots, kit.

The CD V-700 looks a lot like a counter I recall from a stand at
something like the Ideal Home Exhibition, probably in the 1950s. Anybody
with a luminous watch (like me) was asked to put it near the sensor. The
clicks were fed through a speaker, so you could hear them increase
rapidly as the watch got near.

The Smartphone plugin looks intriguing but the blurb isn't that
convincing about background radiation.

They say that nothing on the site should be used for safety critical
purposes.

--
Colin Bignell