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Author Topic: What is RG-8X+F  (Read 3413 times)
AF6D
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« on: May 19, 2011, 05:24:44 PM »

I am looking for an RG8X sized double-shielded for inter-connect cables and was recommended RG-8X+F.

What is it? I've never heard of it.
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W8JX
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« Reply #1 on: May 19, 2011, 06:43:45 PM »

I have a roll of RG-8X low loss in garage but they did not  mark it with a "F"
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KA5N
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« Reply #2 on: May 19, 2011, 07:47:09 PM »

Wouldn't you imagine that +F  just means RG 8X   plus Foil ?

Allen
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W8JX
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« Reply #3 on: May 19, 2011, 09:02:39 PM »

Wouldn't you imagine that +F  just means RG 8X   plus Foil ?

Allen

Makes sense as my roll has braided shield and foil but is just stamped " RG 8X / "
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AF6D
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« Reply #4 on: May 20, 2011, 01:50:01 AM »

Now haven't we all learnd not to assume anything? LOL. Not all RG8X has foil. In fact I've never seen it with foil. Google tells me that it mnight have foil. But I can't find a reputable brand like Belden to confirm that +F means foil. What are the characteristics? Can it be used for patch cables on portable repeaters? What i8s it's loss per 100 feet?
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W6RMK
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« Reply #5 on: May 20, 2011, 07:00:15 AM »

rg8, rg8x, rg8x-f are all just marketing names, anyone can make anything and call it that (there's no valid MIL-SPEC for RG-8 these days, nor has there been for decades).

What you need to do is look at the actual part # for the cable you are considering.  Belden, of course, has 4 digit type numbers (there's probably dozens of quarter inch RG-58/RG-59 type coax from Belden, with different colors, jacket material, etc.)

As for someone suggesting RG-8X+F, you need to ask *them* what they meant.

As far as loss goes, you need to look at the datasheet for the coax you're contemplating.  Basic rules of thumb:
loss goes as square root of frequency (skin effect)
larger coax has less loss (because the conductors are bigger), in roughly linear proportion to diameter (twice the diameter = half the loss)
foam dielectric has lower loss than solid (because the inner conductor can be bigger, not because of dielectric loss)
air dielectric has lower loss than solid (ditto)

You could probably estimate loss by knowing only diameter and velocity factor.

Look at several catalogs to get an idea of what normal loss is for your kind of coax (size, dielectric, frequency).  If the one you are being offered is substantially better or worse, ask why.
That is, there's no secret recipe for low loss.. in a given configuration, the differences between coaxes are things like ruggedness, temperature handling, flexibility, whether it emits toxic gases when burned, etc.
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W0FM
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« Reply #6 on: May 20, 2011, 12:07:19 PM »

I don't know exactly if this is consistent with what you are seeing in the model number, but I have seen coaxial cable marked with an "F" when it had been specifically advertised as "flexible". 

Terry, WØFM
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W0FM
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« Reply #7 on: May 20, 2011, 01:04:23 PM »

This from an expired eBay offering:

RG-8XF is the Low Loss Version of RG8X. It has Copper over Foil so it is Double Shielded etc. It is the same physical size as regular RG8X but is a better quality cable for Ham/CB or other RF applications

Unfornatualy, it's eBay, so there is no good way to verify the description.
 
Terry, WØFM
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KD8DEY
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« Reply #8 on: May 20, 2011, 09:16:54 PM »

Might have better luck finding LMR-240UF Smiley
Good stuff and it fits the same adapters as RG-59/U
« Last Edit: May 20, 2011, 09:19:33 PM by KD8DEY » Logged
AF6D
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« Reply #9 on: May 21, 2011, 03:04:55 AM »

Might have better luck finding LMR-240UF Smiley
Good stuff and it fits the same adapters as RG-59/U

I found the RG8X+F and at a good price. That's what caused me to ask what it is. I too found it described with a sedcondary foil but hadn't heard of it before. A 500 foot roll for $100. I prefer 1/4" Superflex on a repeater but on a portable repeater I thought this might be easier to work with.
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