[Elecraft] Multimeter Altitude Limits

[peter gerba]

Hi Jim;

I understand arcing at standard Temp. and pressure.  I thought that the
reduction of media would produce an increase of voltage Vs. distance (vacuum
relays and Caps.)

I'm missing something here.

pete kn6bi

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net]On Behalf Of n5ib at juno.com
Sent: Thursday, August 03, 2006 5:20 PM
To: Elecraft at mailman.qth.net
Subject: Re: [Elecraft] Multimeter Altitude Limits


In our high altitude ballooning program at LSU (>120,000 feet) it's
necessary to be very careful about sharp edges and corners in circuits of
even modest voltages. Vacuum chamber testing is an essential part of the
payload development. Our student payload had a Geiger-Muller tube, and
that's a couple hundred volts, so they had to be sure to test in the
chamber.

Interestingly... 6500 ft is 1981 meters, so I speculate a conversation
like..

Pointy Haired Boss: We need an altitude limit because of HV arcing, what
do think it should be?
Alice: Oh, couple thousand meters or so should be safe enough.
Pointy Haired Boss: OK, tell marketing.
Alice: Fine, but remember we're selling it in the USA.
Pointy Haired Boss: Not to worry, ad copy writers will take care of
conversion.

I recall a wireless device whose range was specified on the package to be
"up to 328 feet."
Amazing how they knew it would work at 327 but not at 329. Of course what
was meant was that the range was about 100 meters.  :^))

73
Jim N5IB

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