Rg8 coax help

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W2PMX

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Since most 2 and 440 antennas will be 50 ohms, it depends on the cable length you need. I ran a digipeater for many years running 10 watts to 75 feet of RG-8 with an Isopole on the end of it.
 

Rt169Radio

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Well how long is the coax run going to be? Your talking about RG-8 coax and not RG-8U coax right?
 

W2NJS

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Look up a coax specification chart online and decide what's best for your systems. RG8 is a heavy cable, but compared to RG58 or RG8X it has much lower signal loss per foot. RG8U is the RG8 with what they call a non-contaminating jacket, which means the black cable covering will last longer in the sunlight or, in some cases, if it's buried in the ground. Again, you have to check the cable specs and see what's best for you.
 

LtDoc

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Losses increase with frequency with all coaxial cable. If you happen to have a lot of one particular type/size, and if it performs adequately (your choice about 'adequate'), then why not? Comparing specs between different cables is usually how you make a choice. The practical side of that is what's it gonna cost you and is that reasonable too?
I've used a lot worse stuff than RG-8 for a 2 meter 440 feed line! I've also changes to a 'better' cable and there can be quite a difference. So, it's up to you as to what you use. If you've got it on hand, that's certainly better than having to buy it, so, try it and see. At the very least, you'll know better next time, right?
- 'Doc
 

darticus

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This coax is marked Tandy RG-8 Mini Foam. It does not say RG8U. It seems, from reading, that this is better than the RG58 which I use on most CB's and scanners. Again is it better than LMR400? If I run this for 2 meter and 440 do you think it will be ok? Do you think at 50 foot its better than RG58 for 2m and 440?

Would it be better to use RG58 or RG8 MINI FOAM at a 50 foot length? Any thoughts? Thanks Ron
 
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zz0468

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This coax is marked Tandy RG-8 Mini Foam. It does not say RG8U. It seems, from reading, that this is better than the RG58 which I use on most CB's and scanners. Again is it better than LMR400? If I run this for 2 meter and 440 do you think it will be ok? Do you think at 50 foot its better than RG58 for 2m and 440?

Would it be better to use RG58 or RG8 MINI FOAM at a 50 foot length? Any thoughts? Thanks Ron
Tandy? That means it's from Radio Shack. Peel some of the outer jacket off and look at the shield. If you see the white center insulation through the shield, throw the whole roll away - it's crap.

The coax Radio Shack sells has very poor shield coverage, which makes it close to worthless. It is NOT better than LMR400, and is really only useful at HF frequencies and lower.

And even there, I personally would not use it.
 

darticus

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YOU Really hate Radio Shack! Ron

Tandy? That means it's from Radio Shack. Peel some of the outer jacket off and look at the shield. If you see the white center insulation through the shield, throw the whole roll away - it's crap.

The coax Radio Shack sells has very poor shield coverage, which makes it close to worthless. It is NOT better than LMR400, and is really only useful at HF frequencies and lower.

And even there, I personally would not use it.
 

zz0468

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YOU Really hate Radio Shack! Ron
I'm indifferent about Radio Shack. I really hate the low quality stuff they sell. It's really pretty horrendous. I won't touch it, and I try not to let anyone else touch it. It's THAT bad!
 

n5ims

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This coax is marked Tandy RG-8 Mini Foam. It does not say RG8U. It seems, from reading, that this is better than the RG58 which I use on most CB's and scanners. Again is it better than LMR400? If I run this for 2 meter and 440 do you think it will be ok? Do you think at 50 foot its better than RG58 for 2m and 440?

Would it be better to use RG58 or RG8 MINI FOAM at a 50 foot length? Any thoughts? Thanks Ron
RG-8 Mini Foam would translate to RG-8X. At the VHF and UHF frequencies you're asking about it would be just a slight bit better than RG-58, but not enough to worry about. It's much worse than LMR-400 with the 8X giving you 4.0 dB of loss to the LMR-400's 1.3 dB (lower numbers are better). To help compare, Tandy RG-58 would be 4.8 dB of loss while RG-8 would be 2.2 dB of loss.

Your choice would be (best to worst):
#1 - LDF4-50A Heliax (0.75 dB of loss at 450 over 50')
#2 - LMR-400 (1.3 dB loss)
#3 - RG-8 (good quality stuff like Belden) (2.2 dB loss)
#4 - RG-8X (4.0 dB loss)
#5 - RG-58 (4.8 dB loss)

The "Mini Foam" would make good jumpers (if they're short - 6' or less) on the VHF/UHF frequencies. It would be good for HF though since that's what it was designed for. It's a shame that they gave 8X that name since its performance is much closer to 58 than it is to 8 and folks that don't know better can easily be confused and think that they have RG-8 when they really have RG-8X.
 

darticus

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Great info thanks for the input. Ron

RG-8 Mini Foam would translate to RG-8X. At the VHF and UHF frequencies you're asking about it would be just a slight bit better than RG-58, but not enough to worry about. It's much worse than LMR-400 with the 8X giving you 4.0 dB of loss to the LMR-400's 1.3 dB (lower numbers are better). To help compare, Tandy RG-58 would be 4.8 dB of loss while RG-8 would be 2.2 dB of loss.

Your choice would be (best to worst):
#1 - LDF4-50A Heliax (0.75 dB of loss at 450 over 50')
#2 - LMR-400 (1.3 dB loss)
#3 - RG-8 (good quality stuff like Belden) (2.2 dB loss)
#4 - RG-8X (4.0 dB loss)
#5 - RG-58 (4.8 dB loss)

The "Mini Foam" would make good jumpers (if they're short - 6' or less) on the VHF/UHF frequencies. It would be good for HF though since that's what it was designed for. It's a shame that they gave 8X that name since its performance is much closer to 58 than it is to 8 and folks that don't know better can easily be confused and think that they have RG-8 when they really have RG-8X.
 

zz0468

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Pay attention to the shield on that stuff. If it's really thin like Radio Shack coax tends to be, there isn't even enough to properly terminate a connector. Many types of connectors depend on the strength of the shield to hold on, and if there's essentially no shield, the connector will easily pull off.
 
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