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Re: [Amps] 4CX1000A project

To: akozak@hourglass.com, k2vco.vic@gmail.com, amps@contesting.com
Subject: Re: [Amps] 4CX1000A project
From: TexasRF@aol.com
Date: Mon, 28 Oct 2013 08:05:08 -0400 (EDT)
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Hi Vic and All, another hazard with the so called MHV connector is the HV  
wire is not captivated.
 
 Some of the flexible HV wires are quite fragile and can break off at  the 
point they are soldered to the connector. I have the scars on my left hand  
to prove the point.
 
In addition to the SHV connectors, there is a series called EHV made in a  
similar way. One of these has a longer center connection and higher voltage  
rating (I forget which)..
 
Both of these connectors are a vast improvement over the MHV series as they 
 can be used with RG8/RG213 or RG58 coax cable and securely clamp the  
shield. A piece of heat shrink will add even more security to the shield  
connection. Both require a mating chassis feed thru or cable mounted mating  
connector.
 
I am using the higher voltage rated connector in a twt power supply to  
supply voltage via RG213 coax cables to a remote twt. I found that they worked  
well with the 4500vdc collector voltage but not well with the 9kv cathode  
voltage. At 9kv the male connector arced internally.
 
The higher voltage required construction of a homebrew feed thru that works 
 well but is somewhat ugly.
 
73,
Gerald K5GW
 
 
 
 
 
 
In a message dated 10/27/2013 10:20:53 P.M. Central Daylight Time,  
akozak@hourglass.com writes:

Just  FYI, from Wikipedia: 

MHV connectors are presently considered by some  as a safety hazard because 
of the possibility of high voltage on the exposed  central pin when not 
plugged in,[1] and because the ground connection is  broken before the power 
connection when demating. SHV connectors are designed  to prevent these 
hazards, and cannot be mated to BNC connectors.

Always  have liked the idea of separate power supplies but have always 
worried about  the safety of interconnects.  The one other person I know who 
did 
this  did not use any connectors for the HV.  Accomplished the goal 
decoupling  the supply from the amp, but requires tools and time to move either 
chassis  more than the length of the umbilical away from each  other.

Al
AB2ZY

-----Original Message-----
From: Amps  [mailto:amps-bounces@contesting.com] On Behalf Of Vic K2VCO
Sent: Sunday,  October 27, 2013 11:03 PM
To: Amps reflector
Subject: [Amps] 4CX1000A  project

I've added a few more photos to my 4CX1000A amplifier page at  
<http://www.qsl.net/k2vco/4CX1000A/K2VCO%204CX1000A%20Amplifier.html>

I  finished the wiring as well as testing and adjusting the Tetrode Boards, 
which  include the screen and bias regulators and trip circuits, the warmup 
timer,  etc. I have not yet applied HV, which I intend to do when I'm 
fresh, and after  I've cooked the tube with heater voltage only for a while.

I'm working  on adding fans to a '1000 watt' Drake dummy load to use for  
testing.

--
Vic, K2VCO
Fresno  CA
http://www.qsl.net/k2vco/
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