RG-8X or RG-8U

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Rt169Radio

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Hi,I was wondering which coax is the best for 2 meter ham radio? RG-8X or RG-8U
 

kayn1n32008

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What are you doing with it? How long of a run? LMR400 is probably a better choice over RG-8u/x
 

W2NJS

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Back to the original question, 8U is considerably less lossy than 8X.
Do a Google search for coax cable specs and you'll find the exact data.
 

LtDoc

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Nothing wrong with using RG-8X for short runs at 2 meters. That 'short run' thing is typically less than 50 feet, or for mobile use. There's no denying that RG-8X is easier to manipulate than RG-8. So just how important is ease of use to you?
That 'spec' chart for various sizes of coax is a very nice thingy to have around, or at least to compare different cables and frequency usage. Fractional differences just don't amount to anything significant, so don't get too wrapped up in that aspect. The numbers to the left of that decimal point can make a difference, but they have to be larger than 3 to be very significant.
- 'Doc
 

Rt169Radio

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Nothing wrong with using RG-8X for short runs at 2 meters. That 'short run' thing is typically less than 50 feet, or for mobile use. There's no denying that RG-8X is easier to manipulate than RG-8. So just how important is ease of use to you?
That 'spec' chart for various sizes of coax is a very nice thingy to have around, or at least to compare different cables and frequency usage. Fractional differences just don't amount to anything significant, so don't get too wrapped up in that aspect. The numbers to the left of that decimal point can make a difference, but they have to be larger than 3 to be very significant.
- 'Doc
Its says on the specs that RG-8U has a total run attenuation of 1.8,I checked RG-8X and RG-58 coax and the RG-8U has the lowest loss.So it looks like I will be getting the RG-8U.

What did you mean by that RG-8X is easier to manipulate?
 

W2NJS

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8X is about half the diameter of 8U, so it's easier to handle, that's all, aside from the higher loss with 8X. 8X is great for making patch cables, short runs inside the house, etc. but when you go outside and up to the antenna you're usually much better off with 8U or a similar spec large 50-ohm cable. A cable guide from TImes was just listed here on the board today and I bookmarked it, so here it is:

Welcome to Times Microwave | Coaxial Cable - Attenuation & Power Handling Calculator
 

LtDoc

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That 'manipulate' was explained already. It's jut easier to bend, thread though tight places, etc. It's also smaller, that can make a difference at times too. Nothing wrong with RG-8, use it.
- 'Doc
 

mpddigital

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Please remember that that Times attenuation calculator presupposes that you are talking about decent coax meeting their specs. "RG" coax has no detailed specifications as to quality, attenuation or construction anymore so please use some from a good company. The US and most European firms make good stuff as do many of the Taiwan factories that produce cable for 3Com, Cisco etc. Much of the Chinese stuff is pure crap. Brands to look for include Times, Andrew, Coleman, Commscope, Alpha, Suhner, Draka, and others.
 

Rt169Radio

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I got the RG-8U coax,but its quite thick and so I was wondering if 50 feet of RG-8X coax would be good to? I want to use it for 2 meter ham radio freqs.
 

LtDoc

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The 'thickness' of RG-8 can be a problem at times. But, it's certainly manageable in most instances. If you have to do some very tight bending, and can't find another way of doing it, then RG-8X may be an alternative. Just depends on how/where you run the stuff. If it's a matter of 'looks', then hide it in some way (paint it?).
- 'Doc
 

DPD1

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Since you already have the full size 8, you can just get a short 8X patch to go between that and the radio. Then you fix your flexibility issue.
 

Rt169Radio

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Well its hard to close my window on the RG-8U coax and I had to seal up the openness with foam (pieces of foam) and it looks unsightly.I calculated RG-8U and RG-8X coax for 50 feet and the 8U had the attenuation of 2.382 while the 8X had a attenuation of 4.442,is that not good loss? I have about 50 feet of RG-58 coax and that has a attenuation of 5.509,is that even worse? Am really trying to balance functionality and the lowest loss I can get with coax.
 

LtDoc

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Because of that 50 foot run I have to assume this is for a 'fixed' installation, not mobile. If so, then getting feed lines through a window just isn't a biggy. All it takes is a board of the right height and length to fit in that window. Drill a hole in that board, put in a 'bulk-head' connector and feed that coax through that way. A shorter 'jumper' from that window to the radio isn't unreasonable. That bulk-head connector and a couple of PL-259's just won't add enough attenuation to make any practical difference. Or, MFJ makes several styles of those type of window feed throughs too.
- 'Doc

(I've done that 'board' thingy for a lot of years and not just with coax. I can't tell any difference from just opening that window and running the coax directly.)
 

Rt169Radio

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Okay I could try something in the area like that.I have another question,I have about 54 feet long RG-58 coax and 75 feet long RG-8U coax,which one would be better to use for 2 meter ham radio.The RG-58 has a total attenuation run of 3.0 while the RG-8U has a total of 1.8. Is that a big difference?
 
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zz0468

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...I have about 54 feet long RG-58 coax and 75 feet long RG-8U coax,which one would be better to use for 2 meter ham radio.The RG-58 has a total attenuation run of 3.0 while the RG-8U has a total of 1.8. Is that a big difference?
It depends on what the application is. It's not a huge difference if you're just working through repeaters and local simplex. It's a big difference if you're trying one of the weak signal modes where every fraction of a db can make the difference. It's always good practice to use the lowest possible loss cable for any given application.

RG-58 has it's uses where it's a good choice. Base station operation at VHF frequencies is not usually one of them. In the case of trying to close it in a window, maybe the tradeoff is worth it to you. You need to weigh all the factors that YOU have to deal with.
 
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