COAX " cables antenna"

[inertial]

hi ALL,
I wanty know , if exist 150 ohms - impedance characteristyc - of a coax ,solid core ,cable and wher eventually I can purchase some meters ( a lot....)

thanks for reading,

by

Paolo , PHASELESS - HIGH END ,LOW COST SPEAKERS handcrafted in ITALY.

 

[DF96]

Strange as it might seem, Googling '150 ohm coax' might answer your question.

 

[Speedskater]

Paolo, why do you need 150 Ohm co-ax?
Is it for a radio antenna?

 

[inertial]

why 150 ohm coax solid core

Hi, because i put one in go and one in return for my digital hiugh end DIY cabkles......Van den Hul S/VHS 2-75 is not more reperible, unfortunately it was exceptional how digital cables.... ssshhhhh! top secret....

thanks paolo
by

 

[DF96]

Digital audio usually needs 75 ohm cables. To get that with 150 ohm (why??) you would parallel two cables together; the result would probably be bad jitter. I don't understand what you mean by 'go' and 'return'.

 

[marce]

Possibly separating the signal and its return path, the worse thing you can do to a digital signal...

 

[rdf]

hi ALL,
I wanty know , if exist 150 ohms..

The old twinax computer cabling used in AS400 systems: 150 Ohm Twinaxial Cable from Allied Wire and Cable, Distributor of Belden Cable

 

[DF96]

Possibly separating the signal and its return path,

Well, I did wonder but surely nobody could be that daft? That would mean that some people fret over exactly which BNC they use, while someone else happily uses a 300ohm 'balanced' line. It is fortunate the digital audio signals are so robust!

 

[marce]

Thinking about this further (the mention of S-VHS cable threw me) are we talking about:
Twisted pair within a shield or
two co-ax cables within a single shielded cable?
S-VHS used the latter, but the first can be used for balanced signals and digital LVDS

 

[stormsonic]

Yeah, and twin-lead 300 Ohm cable from old TV antenna is twice as good as "just" 150 Ohm

 

[marce]

Don't get it sorry!!!

 

[AndrewT]

= joke.
If the number is twice as big then the performance must be twice as good !

 

[marce]

Ahh yes. Too much time at work and not enough time to think.
I am still trying to get my head round what the original poster wants...
When I was a kid we couldn't afford even the 300Ohm stuff, just used a metal coat hanger, and here I am not joking, worked for years.

 

[inertial]

Thinking about this further (the mention of S-VHS cable threw me) are we talking about:
Twisted pair within a shield or
two co-ax cables within a single shielded cable?
S-VHS used the latter, but the first can be used for balanced signals and digital LVDS

Ihave to explain better,perdone me and my bAD ENGLISH: I WANT USE ONLY THE "core-SOLID", ONE FOR GO AND ONE FOR RETURN.
tHE SHIELD IS ATTACHED ONLY ONE PART ON THE NEGATIVE POLE...
I HOPE TO BE MORE DECENT CLEAR NOW!

BY

 

[inertial]

Ihave to explain better,perdone me and my bAD ENGLISH: I WANT USE ONLY THE "core-SOLID", ONE FOR GO AND ONE FOR RETURN.
tHE 2 SHIELDs ARE "ATTACHED- LINKED" ONLY ONE PART ,ON THE NEGATIVE POLE. ONLY...
I HOPE TO BE MORE DECENT CLEAR NOW!

BY

 

[DF96]

No, its less clear now. You seem to want to use the inners of a 150 ohm coax for both signal and return, with the two shields grounded. If I understand correctly you want to make a 300ohm balanced circuit. If so, why not use 300ohm twin cable? Why not tell us what you want to do then we can advise you how best to do it.

 

[Speedskater]

Maybe something like this, from Henry Ott.

 

[AKN]

inertial,
Se this excellent video: Use a scope to measure the length and impedance of coax - YouTube
Watch what happens with the signal when impedance mismatch occurs.
http://www.youtube.com/watch?v=Il_eju4D_TM

 

[DF96]

Perhaps, but I hope the OP knows about baluns etc. as most audio digital links are 75 ohm.

 

[marce]

The Henry Ott picture from:
http://www.hottconsultants.com/pdf_files/aes-2007.pdf
refers to balanced audio, for digital signals this would not work, using a twisted pair within a shield would work, using one for the signal and one for the return, though you then have the problem of terminating the shield correctly, otherwise you are prone to RF pick up or emitting.