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Coax Cable and Connectors For general discussion of all things pertaining to coax cable, wave guide or any other medium for passing RF energy. This includes connectors, weather proofing and grounding.

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Old 03-30-2008, 7:20 PM
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Question Is RG 8 Foam Type Coax Cable The Best?

Is RG 8 Type Foam Coax Cable, The big stuff good for a scanner antenna/scanner?

I have a whole 75ft of it but I want to make sure it's good before I install it on my scantenna and RS PRO 2050...But I need to know if RG8 Type Coax Cable is better than RG 58 Television Cable and if I should Use RG 8 Type Foam Coax Cable instead of RG 58 Coax?

If anyone needs to see a pic, Let me know, I'll post one...
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Old 03-30-2008, 8:05 PM
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How long is the run going to be??
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Old 03-30-2008, 8:50 PM
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RG-8 is definitely better than RG-58. RG-58 is not TV cable, older cable would be RG-59 and newer stuff would be RG-6. TV cable (RG-59 and RG-6) is 75 ohm impedance, RG-8 and RG-58 is 50 ohm impedance.

So, if you already have the RG-8, go for it. 75 feet would have a bit less than 5dB loss at 800 MHz, which isn't terrible but not great either. If you only need 20 feet or something, definitely shorten it as needed. Of course, if you aren't going to be listening to 800 MHz systems then no big deal - the loss will decrease as frequency goes down.

Edit: This doesn't take the quality of the coax you have into account. Does it have a brand name on it? Most Radio Shack coax is pretty lousy, although they did have a few types that were okay. Belden would be good stuff.

Last edited by n5usr; 03-30-2008 at 8:52 PM..
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Old 03-30-2008, 9:27 PM
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Ok, I don't see a brand name, Just RG 8 + Foam Coax Cable...The run will be the entire length of 75 feet.. Here is the cable I will be using...
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Last edited by btritch; 08-09-2008 at 2:49 PM..
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Old 03-30-2008, 10:59 PM
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No brand name, huh? Where'd you buy that? Did the packaging have any label? There's got to be more information, unless there isn't any. I would beware of using anything that hasn't got some kind of information associated with it.
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Old 03-30-2008, 11:00 PM
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I wouldn't use it. I would use some good cable TV coax.
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Old 03-30-2008, 11:07 PM
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How much loss an I looking at with RG 6 TV cable?
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Old 03-30-2008, 11:59 PM
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Quote:
Originally Posted by btritch
How much loss an I looking at with RG 6 TV cable?
RG6 has a little more loss than RG8. 7.4 db vs 6.0 db per 100 ft at 400MHz. RG11 is more comparable to RG8 both in size and in loss.
Specs for various cables here:
http://www.rfcafe.com/references/ele...coax_chart.htm

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Last edited by thewenk; 03-31-2008 at 12:01 AM..
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Old 03-31-2008, 12:13 AM
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according to that chart RG 88 appears to be the best but where would I find any of those listed? I know the RG 6 and RG 58 are available at RS but what about the best according to that chart?
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Old 03-31-2008, 1:03 AM
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Quote:
Originally Posted by btritch
according to that chart RG 88 appears to be the best but where would I find any of those listed? I know the RG 6 and RG 58 are available at RS but what about the best according to that chart?
According to the chart, RG88 is .7 db /100' at 1 MHz. God only knows what it's loss is at the frequencies you'd be interested. No matter, you'll play hell trying to get your hands on any.

The general consensus from countless threads similar to this one is that your best bet is probably LMR400. It's readily available, and it's performance is quite decent. But why bother? You have some RG8 that will work fine. Trying to extract every fraction of a db of performance out of an antenna system used for a scanner is an excersize in wasted time and money. Once you have a signal that's in saturation, it doesn't matter how much stronger you can get it - you'll still hear it just fine. And the 3 db difference between your brand x RG8 and LMR400? You'll never notice the difference at 75'.

Save your money and put it to better use.
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Old 03-31-2008, 7:33 AM
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I have RG 6, not 8. where can I get 8?
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Old 03-31-2008, 10:22 AM
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Quote:
Originally Posted by btritch
I have RG 6, not 8. where can I get 8?
Your first post said you had RG8, now you say RG6. RG6 will work, if that's what you have.

RG8 is widely available. Any local radio supply store should have it. Do a Google search on RG8 and I'm sure you'll find numerous internet sources for it. This is one source.
http://www.universal-radio.com/catalog/cable/coax.html

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Last edited by thewenk; 03-31-2008 at 10:29 AM..
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Old 03-31-2008, 5:01 PM
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It was early in the AM when I said my last post. NO I DO NOT have any RG 6, I DO have RG 8 which is the title of this thread however numerous people have said not to use it because it has no brand name on it. It is the one pictured above in the previous post..Should I get RG 6 or use what's posted here? which is RG 8 Foam Isulated Coax...75 ft
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Old 03-31-2008, 5:40 PM
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Just get some RG11 or LMR400 and be done with it.
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Old 03-31-2008, 7:04 PM
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or some LDF1-50!!

http://www.radioreference.com/forums...d.php?t=101538
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Old 03-31-2008, 7:06 PM
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Quote:
Originally Posted by Dubbin
Just get some RG11 or LMR400 and be done with it.
I second that. I use RG11 myself.
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Old 03-31-2008, 8:59 PM
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If the run for your coax is simple to do, and it wouldn't be a major undertaking to replace the coax later on, I would go ahead and try what you have. It may be just fine - again, depends greatly on the strength of the signals you are trying to receive.

If you're going to have to go to some significant trouble to get the coax run in the first place, or if you know the stuff you want to listen to is going to be weak (either due to terrain or distance) then go ahead and get the better stuff.

I'm partial to LMR-400, because it is 50 ohm coax, and your scanner and most antennas are going to be 50 ohm (nominally). Using the CATV coaxes (RG6 or RG11) means you will have an impedance mismatch, as they are 75 ohm. The mismatch isn't much, and in the whole scheme of things won't really affect things significantly, but I'm a bit of a purist in that way... (It also matters more to me since my scanner antennas are also able to be transmitted on, I'm an amateur radio operator.)

You mentioned Radio Shack, and I would strongly suggest you get your coax elsewhere whatever you buy. Most of the RS coax I've used in the past had very poor shielding, you could strip the outer jacket back and see the center dielectric through the braid. You want 100% shielding on the coax, to keep noise from further degrading the signal from the antenna.

Cheaper coax cables also may not be made quite to spec, so even though you have RG-8, if it's not properly made it may have more (sometimes significantly more) loss than "real" RG-8. That's why people are leery of the fact your cable doesn't have any identifying marks on it.

Last edited by n5usr; 03-31-2008 at 9:01 PM..
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Old 06-11-2013, 6:03 PM
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Default RG8 vrs RG58

Without a doubt the rg 8 is better however you will not notice any difference if you are only receiving.
Less line loss and less interference with RG8
If 75 feet is enough I would use and not spend more money but that is just me.
Tony
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Old 06-11-2013, 10:27 PM
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Do you have RG8 + or RG8 X? Regular RG8 is about a half inch diameter and RG8 X is a little bigger than a quarter inch dia. If you have X then get something better. Foam type RG8 (non X) is usually fine for a moderate run.
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Quote:
Originally Posted by btritch View Post
Ok, I don't see a brand name, Just RG 8 + Foam Coax Cable...The run will be the entire length of 75 feet.. Here is the cable I will be using...
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Old 06-11-2013, 11:52 PM
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Why not just use what you have? It's not going to be the best in the world but depending on what bands you intend to monitor, a lot of other cables won't be the 'best' either. It's a matter of degree. A dB or two isn't worth worrying about. Other factors will make that much difference all by their selves. Want to try something 'better'? Why not? At least you would the have something to compare that 'better' cable to.
- 'Doc
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