[Boatanchors] Re: [AMRadio] Millen High Voltage Connectors

[Jim Wilhite]

Dave there are other makers of HV connectors out there.  On their high power 
base stations, Motorola use a Teflon one.  They are similar to one sold by 
Surplus Sales of Neb., see here:

http://www.surplussales.com/Wire-Cable/HVWire-2.html

The site says a pair are 14 for the Teflon type and the old style Millen 
tan colored are almost 20. The black are 15.60

Good luck & 73

Jim W5JO


----- Original Message ----- 
From: "david knepper" <collinsradio at adelphia.net>
To: <amradio at mailman.qth.net>; <boatanchors at mailman.qth.net>
Sent: Monday, January 09, 2006 2:50 PM
Subject: [AMRadio] Millen High Voltage Connectors


> My homebrew transmitter,  designed by Stan, W3TGR now a silent key,  is 
> going through exhaustive and often frustrating testing.  Stan used lots of 
> shielded wire - you know the Belden stuff that is deteriorating over time 
> with brittle insulation on the wire. I had to replace several leads 
> because the center conductor was shorting to ground when the insulation 
> became brittle.  So it goes ...
>
> Today, I thought that I had finally debugged the unit - pair of 813's 
> modulated by 805's - but I heard the troubling sound of high voltage to 
> ground.  Measuring the Millen connectors to ground revealed a short.  Here 
> the Millen connectors on the modulator were arcing to ground on the 
> secondary side of the modulation transformer running from the high voltage 
> through the secondary winding to the PA amplifier.   I am using those 
> light tan units that are supposed to be better than the red connectors. 
> Stan used these connectors on the PA amplifier, the modulator deck, and 
> the high voltage power supply.
>
> I suppose that under modulation that the peaks exceeded the voltage rating 
> of the Millen connectors.  Once before many years ago, I had the same 
> problem.  However, these connectors are often used in homebrew 
> construction projects as described in the ARRL handbook.
>
> Any ideas out there other than to go with ceramic feedthrough insulators.
>
> Perhaps, it is because of their age and the insulation is breaking down. 
> Who knows!
>
> Thanks
>
> Dave, W3ST
> Publisher of the Collins Journal
> Secretary to the Collins Radio Association
> www.collinsra.com - the CRA Website
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