Coax types

[Dreven]

What is the difference in each of the different coax types , which would be best for a base station?

[nutcracker]

Lots of different types. Depends on how long of a run you want to do and the power your running. For a low power station, a short run of rg8x, or rg8u will work fine. For longer runs and higher power, anything from lmr400 to heliax is best. I would guess your not running a whole lot of power, and I can recommend rg213 for a decently long run. I am using it for a 60' run and can put 500 through it forever without any heat at all. The rg8x is smaller than the rest but it still a decent quality coax, rg8u and rg213 are almost the same for power rating, 213 is slightly lower loss I believe. The 213 should be all you will ever need unless you decide to pump out over 2 grand. Just stay away from the rg58 either way!

['Doc]

If you would lower the qualifications one 'step', I'd agree with 'nutcracker' mostly. As long as a decent grade cable is used, and if the run isn't over 100 feet or so, there's nothing wrong with using RG-58 size coax at all on HF. If you just have to have 'Times Microwave' cable, try LMR-195 (same size).
Looking at the typical 'spec' chart for coaxial cable, and keeping in mind that losses are 'relative', you can get a pretty good idea of what frequency ranges particular cables are 'good' for. Power handling ability is determined to a great extent on how well the whole antenna system is 'tuned'. That works in 'both' directions for any type coaxial cable, up to and including 'hard-line'.
There's nothing wrong with using the 'high-end' cables, but there's also nothing real beneficial to using them if there's no particular need.
- 'Doc

[Ricky_Bobby]

What would you guys recomend for a run of 150ft I'm running barefoot right now but I'm going to get power in the future in the 500w range to start hopefully more later

['Doc]

I'd say RG-8 as a minimum. From there you're on your own.
- 'Doc

[Dreven]

I am looking at running power as well 500 at least. As far as the length probably 100 feet .

[linx]

I typed out a long thing, but apparently the site went down at the time I hit the submit button.

In a short summary of what I wrote:
I wouldn't do lower than RG-213 or LMR-400. Buy it once, and be done with it.

I did a write up last week about coax losses on these different coaxes. Do a search for it.

[TheCBDoctor]

Hi Dreven

I believe we went through this whole thing on another posting. Linx posted a chart. If he doesn't mind I copied and will try and post it again, but my photos always come out the size of a postage stamp

Doc doesn't mind spending other peoples money and he even said so; nor do I.. In the end the compromise was between practicality and cost. I would suggest using RG-213 because it is not the most expensive and is also very durable and has an insignificant lose at 100 feet I believe Doc said 2db at 100 feet.

I can't find the chart. Well it would have been too small anyway.

Respectfully,

[Dreven]

Ok thank you all for the input I really appreciate it .

[No Handle]

This is the copied information Linx gave me last week. Hope its ok to repost this Linx. Read the post asking about 'any drawbacks to having 200 feet of coax" because the whole group helped me out with great feedback.


Report this postReply with quoteRe: Any drawbacks to having 200 feet of coax?
by linx » Sunday, 07 March 2010, 6:54 AM

YES, there's a huge disadvantage to having 200 ft of coax. Coax signal loss is registered as dB Loss. dB differences in gains or losses on transmit and receive is a very commonly overlooked importance in depending on what type of coax to choose. Major dB loss numbers occur at 100 ft increments.

Here's some examples of dB Loss

RG-58 - 4.7 dB loss per 200 Ft.
RG-8X - 3.7 dB loss per 200 Ft.
LMR-240 - 2.5 dB loss per 200 Ft.
RG-213 - 2.0 dB loss per 200 Ft.
9913 - 1.8 dB loss per 200 Ft.
LMR-400 - 1.3 dB loss per 200 Ft.
LMR-600 - .8 dB loss per 200 Ft.

What does all this mean? Well, the higher quality coax like LMR-400, still only has a 74% efficiency rating at 200 ft, so even with the best coax you will lose over 25% of your receive and transmit signal. Something like RG-8X would be as low as 35-40% efficient. The best on the list, LMR-600 is still 82% efficient.

These numbers are substantial. I have Andrews Heliax hard line on my tower, and between the tower and house (like 20 ft) I use LMR-400 and RG-213. My line loss is pretty much non existent.Admin - CBRT Complaints Department

[linx]

No Handle,
Thanks for posting that. I had made a reply that was long, but not as long as that one, but I lost it in a site "brown out". I didn't want to retype it and I was too lazy to look up last weeks post, lol. Thanks again.

['Doc]

And just like in that other thread...
You have to keep what those losses really mean in perspective. Until they get to something around 3 dB, they really aren't all that important, you'll never 'hear' that small of a difference, and neither will someone on the 'other end'. Especially on HF.
Like it or not, 'perfect' isn't all it's 'cracked up' to be. The 'practical' considerations, as in what's it gonna cost me, is important too (at least to me!). It's not just the 'dollar' cost, there are others in all that.
Some types/grades/sizes of coax definitely do have benefits in certain instances! But all 'instances' are not equal, and you have to keep things in perspective.
- 'Doc

It ain't easy being this cheap!

[linx]

With all due respect Doc, I keep hearing about how much it's going to cost, and how it's going to dig into those pockets, but let's really take this into perspective here. So let's do a run down here.

Low Quality RG8X is about .40 Cents/Ft.
High Quality RG8X is about .60-80 Cents/Ft.
LMR-240 (Times Microwave (Like RG8X on Steroids)) is .54 Cents/Ft.
RG-213U (Mil Spec (Awesome)) is .90 Cents/Ft.
LMR-400 (Generic but Mil Spec) is .84 Cents/Ft.
LMR-400 (Times Microwave) is $1 Per/Ft.
LMR-600 (Times Microwave) is $1.28 Per Ft.

So, at 100 ft, with high quality coax, you're talking $60-80 for RG8X or you can get LMR-400 for $84. The price difference is easily manageable. If you have the money for the cheap crap at $40 per hundred, then hold back a few weeks and save up for the higher quality. Do yourself a favor and get the good stuff...you'll be happier in the end. Plus, the ends are easy to install so don't pay anyone else to do it...do it yourself.

I agree that the difference will be marginal with LOW power on these higher end of the HF bands. RG8X @ 100 ft is about 65% efficient and the dB loss is like 1.9. The LMR-400 @ 100 ft is about 86+% efficent and the dB loss is 0.6.

Now, real numbers. These guys are talking about 500W of power going through the line. With RG8X @ 100 Ft, with 1:1 SWR, the real power output would be 322 watts. With Times Microwave LMR-400 @ 100 Ft, with 1:1 SWR, the real power output would be 432 watts.

It's all simple calculations, but to me, $20-40 to produce 100 real watts makes perfect sense. Plus, the more power you put through it, the more power it's going save. Some people pay hundreds of bucks to produce 100 watts, and you could get out much cheaper by just going down the good coax road.

Doc, I agree that line loss doesn't matter much on the lower HF bands, but I run a tight ship and want my setup as efficient as possible. If I was running like 1.8mhz or something super low, then I could handle running RG8X b/c the line loss would only equal to about 40 watts.

Anyway, more than happy to discuss more if you guys want to.

[Dreven]

Thank you all for the help .

[De_Wildfire]

LMR 400.