You can use Coax seal in a tube thats used to fill in the gap between coax
connectors to keep the moisture, which has teflon. Put that on first then
wrap with teflon tap to close up your gaps. To weather seal it, there use
to be the brown tap like stuff radio shack use to have and it molds itself
You could use Teflon tap, it is used on plumbing pipe threads to prevent
leaks. Some one once told me that 1mill thicknes was good for 1K volts.
--
Jim K9TF
_
Topband Reflector
Good points, as usual, Tom.
Corona --besides greatly reducing the breakdown voltage-- can also generate
ozone, which can gradually break down some dielectric materials. When I
worked at Owens-Illinois in Perrysburg Ohio in the late 70's, they used
large insulated conductors to feed 12 kV 3 phase f
This post is worth reading and saving for homebrewers. Not nearly enough of
us understand capacitors this well.
KK1L noted that there must be either an overlap or a gap in the sleeve
that wraps the inner tube. A gap would create a "hot spot" where the
breakdown voltage would be reduced, while
KM1H
- Original Message -
From: "Richard Karlquist"
To:
Sent: Sunday, September 29, 2013 10:12 PM
Subject: Re: Topband: Homebrew capacitors
On 09/29/2013 07:42 PM, Jim GM wrote:
Could have saved more money with a Piece of RF-9913 or RG8 coax cable
about
25pF per foot
>> Could have saved more money with a Piece of RF-9913 or RG8 coax
cable about 25pF per foot plenty voltage rating.
Per my original post, "I'm working on a project that will require 16
variable high-voltage transmitting capacitors with a maximum value of
200pF." I don't know how one would make coa
On 2013-09-30 17:57, ZR wrote:
In the late 60's I made a coaxial capacitor from a length of RG-17 to
supply most of the C for a 40M Bobtail. A little too big to fold and
the losses were not even worth thinking about.
On 160 with a decent coax what would be the effect of a little loss
besides a li
On 09/29/2013 07:42 PM, Jim GM wrote:
Could have saved more money with a Piece of RF-9913 or RG8 coax cable
about
25pF per foot plenty voltage rating.
Only thing can some one please help me on this, do I connect the
center
conductor on one end of the cable and use the shield on the other en
Hi Jim,
When I used it I connected the center conductor at one end and the braid
at the other end. The bit that I used for the small coupling capacitance
was not very long. Even the short length I used kept the output of one
circuit further away from the input of the other circuit.
Some ante
Could have saved more money with a Piece of RF-9913 or RG8 coax cable about
25pF per foot plenty voltage rating.
Only thing can some one please help me on this, do I connect the center
conductor on one end of the cable and use the shield on the other end? Or
just use the center conductor and shi
I'm working on a project that will require 16 variable high-voltage
transmitting capacitors with a maximum value of 200pF. I think it's
worth reminding ourselves that a coaxial capacitor can be made cheaply
using materials that are quite readily available. For the two
"plates," I used 0.75-in OD al
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