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.
That is why I was wondering if some silicone grease globbed onto the center
pin/dielectric might be a good idea before assembly.
I don't know about other sources for RG213/U SHV connectors so happy
hunting.
The chassis mount connectors I used are panel mount with a long insulator
and solder cup for the wiring. I don't know the breakdown rating but the
insulator is about an inch long and appears to be adequate for a lot of
voltage.
At first I used some PTFE insulated stranded wire with the chassis
connector. That danged wire is the most fragile stuff I have ever encountered,
breaking at the soldered joint a couple of times in a short period. I ended up
throwing it away and stripped the center conductor out of some 8X coax
instead. I have no idea how safe the stuff is to use this way but so far no
issues have arisen and it does not break.
To reduce transmit power loss, the twt amplifier is located outside at the
feed support structure for my homebrew 6.9m dish. There is a weather cover
to protect the amplifier, transverter, preamp, feed and preamp from rain.
The power supply is located in the shack and a pair of RG213/U coax cables
carry the cathode and collector voltages to the amplifier. These two cables
and nine others are all bundled together to form a rotator loop. This loop
has to handle a full 360 degree azimuth rotation as well as a 90 degree
elevation travel.
No, I did not use Belden RG213/u for this. I found the Texcom brand coax
and control cables sold at Texas Towers to be totally adequate for the job.
Several of the other cables are various sized Times Microwave LMR Ultraflex
cables.
With 125 watts output power at 5760 MHz, the moon echoes peak about 25 dB
above the audible noise floor and SSB echoes sound like 5 by 7 signals on
20m!
I believe there are now four USA stations operating EME on this band. We
sure could use some company!
73,
Gerald K5GW
In a message dated 9/11/2010 9:26:20 A.M. Central Daylight Time,
jim.thom@telus.net writes:
Date: Sat, 11 Sep 2010 08:35:48 EDT
From: TexasRF@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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