[Test-Equipment] Megger, high voltage probe

[Rasputin Novgorod]

Hi Guys:

I found some interesting things at a Hamfest this weekend,
for which I hope you can give some advice.

1) Megger
I got a Evershed & Vignoles, London, Megger for $30, see photo:
http://www.ontariorocks.ca/temp/megger.jpg

It takes a 4 volt (!) battery (I'll try 3 "C" cells), and
is in a Bakelite box in a leather case. It has a "scale" 
switch (high & low) plus a trigger button on one of the probes.
The instructions show touching the probes to the terminals 
of an electric iron (for flattening clothes) and touching the
trigger button to read the ohms.

a) What is the difference between a Megger and ohm meter?

b) I've been told to use a Megger to test soil resistance
between two ground rods in an antenna system; resistance below
5 ohms is good. I've also been told that you use a megger to
test insulation resistance in cables and antennas. Can anyone
shed some information about this?

2) High voltage probe
I bought this high voltage probe for $20; see photo;
http://www.ontariorocks.ca/temp/probe.jpg

There are no markings on the probe, except a piece of
tape with "137 times" written on it. I was told to swap
this with my VOM probe and I could read high voltages.
I was to take the VOM reading and multiply it by 137.

Is anyone familiar with this thing? I'd like to measure
a 1600 vdc powersupply and a 3700 vdc amplifier plate.
Will the probe work on DC and AC?

3) Electro-Capacitor Sub Box
I bought this gorgeous Bakelite electrolytic cap box, see:
http://www.ontariorocks.ca/temp/cap.jpg

No questions, just bragging; I got it for $1. It has four
values: 10, 20, 40 and 80 uF @ 450 vdc, each individually
switched to give a range of 10-150 uF. Given that Electro-caps
are the first thing to go in old gear, this should be very 
useful for troubleshooting. It had 4 calibration stickers;
what idiot would send a cap sub box like this out for calibration?
(I'll check the caps in the box before using...)

Sincerely
/b

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