Coax (shielded) cable

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pula58
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Coax (shielded) cable

Post by pula58 »

I have a batch of RG 187...the inner conductor is SO thin...makes me worried about long term reliability.

What are you folks using for Coax that has a reasonably low capacitance per foot, but also has an inner conductor that is robust.

I had some RG 187 from Apex Jr..loved it..

Then I got another batch...and on this batch the inner conductor seems extremely thin/frail.
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Post by Stevem »

You should not need anything more than 22 ga to use within a amp and with the currents involved .
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pula58
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Re: Coax (shielded) cable

Post by pula58 »

the inner conductor of this coax is way thinner than 22 AWG. I am concerned about reliability in terms of mechanical reliability, not current limits.
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Phil_S
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Re: Coax (shielded) cable

Post by Phil_S »

What I'm finding says it's good for 1200V. http://www7.taosnet.com/ebear/coaxlist.html The wire size of the inner conductor is listed as .012" http://www.timesmicrowave.com/products/ ... ads/54.pdf which is roughly the size of 28AWG. 22AWG is .0254" diameter.

In general, I dislike working with the inner conductor on coax because it doesn't hold a twist and is difficult to solder. It just doesn't play nice. Am I using the wrong stuff?
sluckey
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Re: Coax (shielded) cable

Post by sluckey »

I like RG-316. The PTFE insulation make it very easy to work with. Approx 1/8" diameter. Silver plated braid and center conductor. Very easy to solder and you will not melt any insulation.

[img:1024:768]http://sluckeyamps.com/VAC15/14.jpg[/img]
labb
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Re: Coax (shielded) cable

Post by labb »

I use RG-174. Never had any problems with it.
pula58
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Re: Coax (shielded) cable

Post by pula58 »

the inner conductor of this coax is way thinner than 22 AWG. I am concerned about reliability in terms of mechanical reliability, not current limits.
davent
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Re: Coax (shielded) cable

Post by davent »

Secure the cable to the chassis so it can't flop about and there should be no strain on the soldered joints.

And... PTFE coax like pictured, is a joy to work with, i've some Teflon/Kapton that's terrific.Very small outer diameter, maybe 26awg inner conductor. Been using for years, never an issue.

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Re: Coax (shielded) cable

Post by ApexJr. »

pula58 wrote:I have a batch of RG 187...the inner conductor is SO thin...makes me worried about long term reliability.

What are you folks using for Coax that has a reasonably low capacitance per foot, but also has an inner conductor that is robust.

I had some RG 187 from Apex Jr..loved it..

Then I got another batch...and on this batch the inner conductor seems extremely thin/frail.
I find that odd
The RG 187 A/U is mil spec and should be pretty close to the same.
I do stock other numbers and also 24 and 20 Awg single conductor
Shielded too.
andresound
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Re: Coax (shielded) cable

Post by andresound »

I have used this cable as well. This a great sounding cable. The center conductor IS thin!! :shock: However, I cable tie and secure cable on something. There is a 75 ohm version (RG179) and it is thicker.
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UsableThought
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Re: Coax (shielded) cable

Post by UsableThought »

What is wanted for wiring an amp is not called coax, but "shielded hookup wire." When I think of coax, it's for things like carrying an FM or cable TV signal for relatively long distances, vs. the short distances required in an amp chassis - for coax the inner insulation is typically a heavy plastic one-piece surround; and there are probably other differences as well. See Wikipedia:
Coaxial cable differs from other shielded cable used for carrying lower-frequency signals, in that the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line.
Anyway, seems a simple problem to solve - if you're not happy w/ the wire you're using, buy some that you know will be satisfactory. I had some braided shield wire I had used for a wiring harness in a guitar - okay stuff except the braid was naked, so I was having to add heatshrink, very laborious. So I went to Digikey - like Mouser they make it easy to filter for whatever you want, e.g. PTFE insulation, etc:

Product Index > Cables, Wires > Single Conductor Cables (Hook-Up Wire)

I ended up choosing a very nice & quite inexpensive PVC-jacketed 22AWG shielded wire - and MUCH better prices than you can get at TubeDepot or Small Bear or wherever:

https://www.digikey.com/product-search/ ... 2030-00342
FourT6and2
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Re: Coax (shielded) cable

Post by FourT6and2 »

I've had good results with RG-188/U. The white Teflon stuff from Belden.

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joesatch
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Re: Coax (shielded) cable

Post by joesatch »

I am on the hunt for this cable. Only can find it on Amazon for $240. Anyone know where i can buy Belden RG-188A/U ? I might connect the shield to my V1 plate so it needs to be serious cable to be safe over 1000v rating.
sluckey
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Re: Coax (shielded) cable

Post by sluckey »

joesatch
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Re: Coax (shielded) cable

Post by joesatch »

i saw that. It's not Belden at least it doesn't appear to be. Can it withstand 1000v?
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