[Amps] SHV connectors great, but where to find coax?

[Jim Thomson]

From: TexasRF at aol.com 
Sent: Saturday, September 11, 2010 6:03 PM
To: jim.thom at telus.net ; amps at contesting.com 
Subject: Re: [Amps] SHV connectors great, but where to find coax?


Hi Jim, I could not find any ratings for the P{asternak connectors. When I received them, I was a bit dubious of them handling enough voltage. 

The dielectric of the center conductor of the coax has to be left about a quarter inch or so longer than a typical connector and it fits down into the connector to provide the needed leakage path. I installed one connector on the RG213/U and tested it for breakdown. I found none at 10 KV so stopped and used the connectors.

The Pasternack's  are all  SHV-5  [ 5 kv rated].... including the ones they sell, that take 213 coax.   Other's sell  SHV-10 and also SHV-20. [ male ends]   I have not found a source for the female chassis  bulk head  SHV-10/20's.  

That is why I was wondering if some silicone grease globbed onto the center pin/dielectric might be a good idea before assembly.

I researched this out really good.    Dow Corning DC-4 has a LOT of electrical applications listed..under "applications".    And DC-4  has a break down of  1000 v  per  .001"  .     I was told by Ken Hirchberg at cal-av labs to use it on the pins of all my   7-6 Din  coax connectors... and also on the threads. 

Other's  will use  DC-5  and also  Dow corning ... " high vac grease" .    DC-5  has NO  electrical applications listed under "applications".    DC-5 is only 450 volts  per .001"         
Dow corning ...." High vac grease has NO electrical applications listed under "applications".   It also does NOT list  any V breakdown.  




I believe there are now four USA stations operating EME on this band. We sure could use some company!

I have a hard enough time on HF..never mind  EME.     I will defer to Lionel Edwards for the EME stuff.  [VE7BQH]..who gave a talk at our local club... back in 1969.   That guy is hard core EME. 

Later... Jim   VE7RF 

73,
Gerald K5GW

In a message dated 9/11/2010 9:26:20 A.M. Central Daylight Time, jim.thom at telus.net writes:
  Date: Sat, 11 Sep 2010 08:35:48 EDT
  From: TexasRF at aol.com
  Subject: Re: [Amps] SHV connectors great, but where to find coax?

  Dave and all, the last SHV connectors I purchased were from Pasterrnak, the 
  high priced specialist folks.

  They have SHV cable and mating chassis connectors for RG213/U coax. II  
  wanted the security of extra voltage handling because of around 10 KV used in a 
  twt power supply.

  The coax connectors were about $25 and the chassis connectors were about  
  $15.

  They worked out really well and I will never use any other type of hv  
  connector on future projects.

  A three inch length of heat shrink was installed on the cable ends for  
  reinforcement and added mechanical security for the coax shields. This is a  
  cheap and effective way to add protection in a critical for safety  location.

  I have wondered if adding a dab of silicone grease to the center pin to  
  coax dielectric area before connector assembly might be a good idea to 
  eliminate  air gaps and moisture traps. Any opinions on that?

  73,
  Gerald K5GW

  ##  I looked up SHV on wikipedia... and it sez  a SHV is only good for 
  3500 v rms ... so add 41% = 5 kv dc.   They also say there  are higher 
  voltage.   I looked and couldn't find anything from anybody...that was more
  than 5 kv.    This version you found from pasternack.... other than it takes
  213u size coax... does the mating female chassis  connector + 213-U size
  male..rated for 10kv ??  

  ##  one could also probably use use RG-393  teflon coax.   It's a tiny bit
  smaller than 213.   [.390"  vs  .405"]   RG-393 is solid teflon dielectric... and is
  probably overkill... but I have loads of it. 

  ##  I just may have finally found a HV connector I like... provided it handles
  8 kvdc..safely.   I gave up on Aldens, Millens etc.  I then just hardwired the B+
  at both ends..with sta-kon crimp connectors [also soldered]... and machine screws.
  Takes awhile to get apart though. 

  ##  Is pasternack the only ones who carry  RG-213 size  SHV male connectors ? 
  Is the chassis female a regular  SHV chassis connector... or a special  10 KV
  rated one ??  

  Tnx........ Jim   VE7RF   

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