Changes in electrical length of bent coax cables

[Cursitor Doom]

On Mon, 02 Mar 2020 08:24:52 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

If you made a bet with your drinking accomplice, what is my share of
your winnings for providing you with answers, entertainment, and
insults? In the future, could you please be more specific as to what
you plan to do with the gathered information? That should help me
decide if it's worth my time trying to answer your question. It
should also help distinguish between whether you are trying to solve a
problem or create one.

A pretty good guide is if I mention specific equipment and
measurements. If I do, it's a real problem; if not, it's purely
hypothetical.

I just realized that your question, "bending coax changes its
electrical length" is easily misinterpreted. Changing the electrical
length of the coax, without changing its physical length, implies a
change in velocity factor. Bending the coax doesn't do that as long
as the dielectric remains intact. Please send my share to the address
below.

Naturally, Jeff, you're always top of my list when it comes to dishing
out gratuities.

 

[Chris Jones]

On 02/03/2020 21:54, Tom Gardner wrote:

On 02/03/20 10:20, Cursitor Doom wrote:
On Sun, 01 Mar 2020 23:34:02 -0800, Jeff Liebermann <jeffl@cruzio.com
wrote:

I provided an eBay link to a $15 TDR that I suspect even you can
afford to purchase.  I have 2 or 3 of them (one accidentally stolen
from a client).  I've built a few others with somewhat better
performance.  They're not the best performers and you won't be looking
at picosecond pulses or GHz responses with one, but such a simple TDR
and a common 100 MHz oscilloscope might possibly be suitable for your
unspecified application.

Jeff, all it arose from was an argument with a chum of mine in the pub
the other evening. He said "bending coax changes its electrical
length" which I felt was a blanket statement worthy of deeper
investigation; that's all. It had *nothing* to do with any real world
situation or problem!!

It would have been courteous to everybody else if you had
stated that in your post that started the thread.

As it is you have encouraged several people to waste their
precious time giving you detailed answers.

Also, as he claims to have the necessary equipment to measure it, and a
chum willing to spend time in the pub with him, why would he not have
invited this chum to go to the VNA and they could measure it together,
in order to settle the argument one way or the other. Surely this would
be a more convincing conclusion to the argument than some opinions
expressed on Usenet. Or perhaps this chum already knew the answer and
didn't feel inclined to waste any further time on the topic.

 

[Tom Gardner]

On 03/03/20 01:43, Chris Jones wrote:

On 02/03/2020 21:54, Tom Gardner wrote:
On 02/03/20 10:20, Cursitor Doom wrote:
On Sun, 01 Mar 2020 23:34:02 -0800, Jeff Liebermann <jeffl@cruzio.com
wrote:

I provided an eBay link to a $15 TDR that I suspect even you can
afford to purchase.  I have 2 or 3 of them (one accidentally stolen
from a client).  I've built a few others with somewhat better
performance.  They're not the best performers and you won't be looking
at picosecond pulses or GHz responses with one, but such a simple TDR
and a common 100 MHz oscilloscope might possibly be suitable for your
unspecified application.

Jeff, all it arose from was an argument with a chum of mine in the pub
the other evening. He said "bending coax changes its electrical
length" which I felt was a blanket statement worthy of deeper
investigation; that's all. It had *nothing* to do with any real world
situation or problem!!

It would have been courteous to everybody else if you had
stated that in your post that started the thread.

As it is you have encouraged several people to waste their
precious time giving you detailed answers.

Also, as he claims to have the necessary equipment to measure it, and a chum
willing to spend time in the pub with him, why would he not have invited this
chum to go to the VNA and they could measure it together, in order to settle the
argument one way or the other. Surely this would be a more convincing conclusion
to the argument than some opinions expressed on Usenet. Or perhaps this chum
already knew the answer and didn't feel inclined to waste any further time on
the topic.

Agreed.

Quite a few people have a low opinion of Cursitor Doom.
I don't think this will have enhanced his reputation.