[AMRadio] problems

[Brett Gazdzinski]

Why use these things?

I gave the ones I had away.
 
I like big ceramic feed through insulators better.

No restrictions on the size of the wire you can use, and they
wont arc over.

Not quite as safe as the enclosed Millen parts, but I don't
mess around in back with the voltage on.

I would not even with the Millen bits, as HV can jump
through the actual HV cable, and unless the rig is completely
enclosed, there are likely other things that can get you.

The Millen things don't look good for much voltage.

My big rig runs a modest 2000 volts, but under modulation,
and with inductive mod transformers and so on, spikes likely
get very high.
I arced over a moderate size ceramic feed through between the mod
cabinet and the rf cabinet (rf side of mod transformer).
It was a hard problem to find, the transmitter acting very
odd under modulation.
The insulator was a good size, bigger than the Millen things, but
it was not good enough.
I changed them to big ones that had a 1 inch hole filled with ceramic
(1/2 inch all around) and don't have problems any more.

I also added a string of high value 2 watt carbon resistors across
the mod transformer secondary to absorb spikes when I un key.


Brett
N2DTS

> 
> project is going along fine. I had to order a couple of small parts 
> today that will likely be in on wednesday. I also need to find a few 
> millen HV safety terminals.. they have a 20 piece minimum order
> so that blew my plan of getting some ordered out the window. I 
> need
> a pair of black ones and a pair of red ones.. caps and chassis 
> mount part.. got any in  your junk box?
> 
> failing that I think I'll see if I can put a order together 
> from the 3880 
> gang.. maybe some of them will want 2 or 3 of them and we can 
> make up a minimum order.
> 
> got the hv supply for the 805's done today, but need one of those 
> millens for it, and a feed through style 6 contact terminal block, 
> ordered that today.
> 
> Got to get to work on the speech amp next
> 
> R
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