Re: Dressing RG6

Jeroen Belleman <jeroen@nospam.please> wrote:

On 5/14/24 23:46, Phil Hobbs wrote:

John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:

On Tue, 14 May 2024 19:22:12 -0000 (UTC), "Don" <g@crcomp.net> wrote:
 

Phil Hobbs wrote:

Phil Hobbs wrote:

Don Y wrote:

I've several short (a few feet) lengths of RG6 that I
would like to "strongly coerce" into assuming a particular
dressing.
 
Securing the cables to a stationary surface isn't practical
without significantly lengthening them and distorting
their "natural" routing.
 
But, ISTM that I should be able to slip each cable into
a comparable diameter copper (?) pipe and then use traditional
tools to bend that pipe into the appropriate configuration.
I'd have to observe constraints like minimum bend radius
but are there other issues that I might "discover" down the
road?
 
 

 
You’re planning to make a random- length shotgun balun.

 
Bazooka balun.

 
The parasitic capacitance created between coax and its metal armor can
open a Pandora's box of potential problems.
 
Danke,

 
Capacitance between the coax outer and the copper pipe? Proper coax
shouldn't have any external field.
 
 

 
If the whole system is really coaxial, that’s true. Leaky shields, ground
loops, and so on, will modify that.
 
Depending on the application, you may or may not care.
 
Cheers
 
Phil Hobbs
 

 
I've been putting coax inside copper tubes or braids to measure
and/or reduce the transfer impedance (leakage). I did that to
measure small signals in a particle accelerator, which typically
has kicker magnets and RF cavities with kA currents and kV
voltages nearby.
 
A colleague developed a special low transfer impedance coax
cable for this sort of application. It had two screens with
intermediate magnetic shielding. It was unpleasant to work
with, because part of the magnetic shielding was a steel
spiral foil tape that was razor sharp. But it worked really
well.
 
Jeroen Belleman
 

Interesting, thanks.

Is that better than real solid copper hardline or (my fave) RG402
semi-hardline? 

I’d like to read more about it, if you have a reference handy.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics