Ive been saying for decades on here and elsewhere that the Millen connectors
are death traps.
Yet some of the same people whining about the PL-259 defended the Millen in
the past on here as "gee, its rated to 7500V by golly by gosh" I guess its
due to selective memories or simple 2 faceness....no surprise there either.
For those who grew up with SS only Id suggest going the full mile and
heremetically seal all HV away from the operator. Operate in a hazmat suit
if it makes you feel safer. Or stick to barefoot power and find another
forum to discuss lifes difficulties and whether you may be hit by a
meteorite.
For those who grew up with the HV coming in via a piece of zip cord to a
ceramic feethru with the hardware exposed, B- and ground both being the same
wire to the chassis, the plate meter in the HV lead, and the PS and
modulator being wide open with HV exposed, Id say we have lived a charmed
life and hopefully have at least made a few improvements along the way. Look
at the old QST and HB articles for examples of what was considered good
practice back then.
I still see plenty examples of 40-50's construction at hamfests and not all
are original examples either. Those scare even me!
Carl
KM1H
----- Original Message -----
From: "Patrick Barthelow" <apolloeme@live.com>
To: <sam@owenscommunication.com>; <david.kirkby@onetel.net>;
<amps@contesting.com>
Sent: Tuesday, September 14, 2010 8:47 AM
Subject: Re: [Amps] SHV connectors great, but where to find coax?
>
> Sam,
>
> Your HV encounter confirms my long held concern about the Millen HV
> plastic connector. Appears to not be "hermetic sealed" with respect
> keeping the HV inside, if a hand is ever brushed over the outside.
> Another failure mode I saw for that connector, if the environment allows
> motion the B+ cable, as I recall the plastic Millen connector shell is
> captured to the cable, by the soldered large diameter center pin, to the
> relatively narrow conductor, passing through a small hole in the shell.
> If that soldered connection fractured, through fatigue flexing, etc the
> Hot, raw end of the B+ lead will pop out of connector hanging in mid air,
> energized. Because of that concern, I got (already had) some neat
> aftermarket shielding tubing. It was a finely made, loose woven,
> metallic "tube" that looked and behaved like a chinese finger trap toy. I
> ran that the whole length of the Drake L-4B B+ lead from the PS chassis
> to, AND OVER the Millen connector, so as to have a metal shi
> eld completely surrounding the millen connector, to its base, and bonded
> to the L4 Chassis. You could use a bananna plug Jack termination for the
> shield wire to make for easy connects, and disconnects.
>
> Best Regards,
> 73, de Pat Barthelow AA6EG
>
>> From: sam@owenscommunication.com
>> To: david.kirkby@onetel.net; amps@contesting.com
>> Date: Tue, 14 Sep 2010 08:30:43 -0400
>> Subject: Re: [Amps] SHV connectors great, but where to find coax?
>>
>> I think the right answer may be to MARK "HIGH VOLTAGE" Even when
>> unplugged
>> or some such. One of the "fit and proper" connectors for HV got me once
>> and
>> I was very lucky. I had a rack-mount Henry 2002 220Mhz amp at a remote
>> location. It has the HV PS in one enclosure and the PA in another.
>> Between
>> them was the HT lead that looked like a spark plug cable and had the
>> Bakelite screw-on type connectors.
>>
>> I reached behind the PA to disconnect the BNC for the RX'er to hook up a
>> service monitor and got the surprise of my life. The palm of my left hand
>> brushed the HV "Proper Connector" and it arched into my hand and exited
>> my
>> elbow that was rested on a basement wall. Had by fate my elbow at the
>> wall...the exit may have been my through my shoe. I had a painful hole in
>> my
>> hand for months and a numb arm for a few days. Also had a nasty exit
>> wound
>> on the elbow.
>>
>> My point is that there may not be any "SAFE" HV connector for the
>> uninitiated. Marking things with stickers spelling it out may make the
>> whole
>> "which one" discussion unimportant. Good marking should avoid problems.
>>
>> Just my 2 cents,
>> N9FUT
>>
>> -----Original Message-----
>> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>> Behalf Of Dr. David Kirkby
>> Sent: Tuesday, September 14, 2010 6:51 AM
>> To: 'AMPS'
>> Subject: Re: [Amps] SHV connectors great, but where to find coax?
>>
>> On 09/13/10 05:46 PM, DAVE WHITE wrote:
>> > "The Engineering Council in the UK would I expect strip someone of
>> > their CEng status if an individual proposed such silly things."
>> > But let's face it, the UK is becoming just about the most laughable
>> example of the socialist Nanny State taken to the most extreme
>> interpretation of the concept. I doubt if Henry V and Winston Churchill
>> are
>> turning in their graves when they see modern Britain, I'm sure that
>> they're
>> spinning like steam turbines.
>> > This is the country where the Elf'n'Safety nazis (including rooms full
>> > of
>> overpaid, interfering, sanctimonious buffoons like the Engineering
>> Council)
>> invade every aspect of our lives. I say Bollocks to the lot of them. If I
>> want to build an HT lead with a PL259 on the end of it, then that's what
>> I'll damn well do and I personally will take the risk. If I plug one end
>> into the 6kV supply and the other into my right nostril then that's my
>> own
>> fault and my own responsibility, right?
>> > Dave G0OIL (not SK, amazingly)
>>
>> cp $above-email /dev/null
>>
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