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Re: [Amps] Why not to use coax connectors for HV

To: "'Carl'" <>, <>, "'Amps reflector'" <>
Subject: Re: [Amps] Why not to use coax connectors for HV
From: "alexeban" <>
Date: Fri, 28 May 2010 15:04:22 +0300
List-post: <">>
If the guy is so accident prone he shouldn't use a screwdriver.
Seriously guys: are you radio amateurs or what?
Using that reasoning, you should not use a power plug on a cord!!
Alex    4Z5KS

-----Original Message-----
From: [] On
Behalf Of Carl
Sent: Tuesday, May 25, 2010 6:18 PM
To:; Amps reflector
Subject: Re: [Amps] Why not to use coax connectors for HV


The PL-259 has been used in industry for decades to carry HV.

Sometimes it requires responsible individuals to work around HV and not some

of the untrained nincompoops we all have run into these days.

IF you feel safe using what you built and are not prone to Alzheimers or 
drunken operating then by all means use them. A safety sign by the connector

is a good idea.


----- Original Message ----- 
From: "Bill, W6WRT" <>
To: "Amps reflector" <>
Sent: Monday, May 24, 2010 7:05 PM
Subject: [Amps] Why not to use coax connectors for HV

> Recently, a couple of members of this reflector suggested using coax
> connectors for high voltage. This is a very unsafe idea, especially if
> used with actual coax cable, and here's why:
> Assuming you have an SO-239 female connector mounted on the power
> supply and you either have the HV accidentally turned on or have not
> fully discharged the filter caps. When you go to plug in the PL-259
> plug you are no doubt holding the metal ring of the PL-259, which
> means you are connected to the braid. At the moment the pin contacts
> the socket of the SO-249, if there is any current path or leakage from
> the coax center conductor to the braid, you are at the full HV
> potential. Even without a DC current path, there is still the
> capacitance between center conductor and braid, and at high voltage
> levels, can deliver a severe shock.
> If you (or some future user of your amplifier) accidentally plugs in
> an antenna to the SO-239, the possibilities are even more dangerous.
> Many antennas are at the same DC potential between center conductor
> and braid because a tramsfprmer-type balun or other matching network
> is present, and you can imagine the consequences of a direct DC
> connection. Even without a balun, a long length of coax has a very
> large capacitance and can easily deliver a lethal shock.
> Even if you are not using actual coax (no braid), do you really want
> to be holding on to a metal ring at the moment the plug pin contacts
> the HV and there is a possible carbon track or other leakage in the
> plug?
> A properly designed HV connector makes this kind of accident
> impossible. Please don't try to save a few bucks by using the wrong
> connector for the job.
> Murphy is alive and well, waiting patiently.
> 73, Bill W6WRT
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