KV meter

["David Euans" <davidwe-at-telocity-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I am trying to build a 50 KV high voltage meter for directly measuring
the voltage from my various high voltage transformers.  I have tried
using a 100 microamp full scale DC meter with one 250 (32 KV) megohm
resistor on each leg and an 80 KV diode string (four 20 KV units)
directly off of one side of a 9 KV neon sign transformer in series with
one of the 250 megohm resistors, but I get faulty readings each time.
Using Ohm's law, 500 megohms should yield 18 microamps at 9 KV, but I am
only getting about 5 microamps of output.  I have tried several
different diodes, but get similar results regardless.  The NST is
working properly.  Am I missing something here?   The diodes seem to be
dropping too much voltage.  If anyone knows how to properly set up a
voltage divider circuit for measuring AC with a DC meter, I would love
to hear it.  To illustrate, my circuit is as follows:

bushing x-----80kv diode-----250 megohm resistor----- +

9
KV
100 microamp meter
NST
(50 KV full scale)


bushing x-----------------------250 megohm resistor----- -