Recommendation on "buryable" coax?

[raisindot]

In case anyone asks, yes, I've searched the site but haven't found the clear answers, so I'm asking you experts.

I'd like to move my PAR connector box away from my window to a location about 50 feet away to help quell some of the internal noise I've been getting on my SW receiver (I also want to get the ground rod away from the house as well--I get very nervous about having it so close to the house during lightning storms). I'm using a simple longwire antenna attached the PAR--nothing fancy.

Anyway, I want to run a 60-70 feet coax cable about about 6" underground from the house to the box. I'm not so worried about a minor loss of signal. Since Since I'm not good at crimping and other cable-making things, I'm looking for a cost-effective pre-assembled cable with standard PL-259 couplings on either end. With that in mind:

1. What kind of cable type would last longest buried underground and exposed to winter cold and snow at the connector ends?

2. Which companies would provide this kind of cable at the lowest cost?

Thanks in advance for your knowledge!

Suzie

 

[N_Jay]

First, look for a cable rater for "Direct Burial".
Second, even with a direct burial cable, protecting it in conduit is a good practice.
Third, even in conduit you must use direct burial cable, as any conduit underground is a wet location.
Fourth, moving the ground rod away from the house does not remove the requirement that the two ground systems be properly bonded together.
Fifth, having two ground points far apart is likely to increase the opportunity for significant voltage differential during direct or nearby lightening strikes.
Sixth, having ground systems far apart increases the difficulty in bonding properly and increases the change of ground loops.

 

[gewecke]

Also there is a term you should look for; non-contaminating. That is cable that can be buried without damaging the soil. There is a poly-whatsit cable too,and that's the crap that you don't bury because it will rot as time goes by. Polyurethane...that's it! Memory is low on ram today,lol!
N9ZAS.

 

[N1BHH]

I used some triple shield cable a friend gave me, it was leftover from CATV installs, that worked very nicely for feeding my various HF antennas at the time, 25+ years ago. It did very well, even though it wasn't rated for burial. I used it for a couple dipoles and a self optimized G5RV at one time. No RFI whatsoever.

 

[gewecke]

By chance do you remember what it was? I have a big roll of tri shield with most of the marking worn off.
N9ZAS.

 

[WayneH]

First, look for a cable rater for "Direct Burial".

Or indicated as "flooded" which is another way of saying it's capable of direct burial. You can purchase LMR-400 in a flooded version or go cheap and use flooded CATV cable in a smaller size.

 

[BuffaloJustice]

...I also want to get the ground rod away from the house as well--I get very nervous about having it so close to the house during lightning storms...

Suzie

N-Jay already said it, but it's worth repeating. It MUST be bonded to the service ground. Having it close to the house is not inherently dangerous, not bonding the two is extremely dangerous whether one is close to the house or not. Check out the Grounding Bulkhead Wiki and check out the links in the thread for more information on grounding and bonding.

I also advise direct burial cable and run it in conduit. If it's buried in a yard and not being driven over I'd use pvc for the conduit.

 

[N_Jay]

Or indicated as "flooded" which is another way of saying it's capable of direct burial. You can purchase LMR-400 in a flooded version or go cheap and use flooded CATV cable in a smaller size.

I believe (which is distinctly different from "I know") that "flooded" cable is rated for wet locations, but may not be suitable for direct burial.

I would guess most (but not all) cable that us marked "flooded" may also be "direct burial".

 

[phatboy48]

Burying standard coax cable

Another trick that I have used for years the two way service field is to get some good low loss cable like standard LMR 400 and run it inside a length of el-cheapo plastic garden hose. Since the hose and it's connectors are obviously waterproof, this is a good way to bury standard coaxial cable without resorting to flooded cable or expensive copper jacketed hard line cable. Just bring the hose/cable above grade at each end with an inverted "J" to keep water from entering the hose from the ends.

73
John.....W8JNC

 

[N_Jay]

Another trick that I have used for years the two way service field is to get some good low loss cable like standard LMR 400 and run it inside a length of el-cheapo plastic garden hose. Since the hose and it's connectors are obviously waterproof, this is a good way to bury standard coaxial cable without resorting to flooded cable or expensive copper jacketed hard line cable. Just bring the hose/cable above grade at each end with an inverted "J" to keep water from entering the hose from the ends.

73
John.....W8JNC

Yes, "El Cheapo", but based on some very bad assumptions.

ANY (yes, ANY) buried conduit, hose, tubing, etc, is a "wet" location.

Even if "water" does not get in (and it will), water vapor will get in, and will condense and will fill the hose, pipe, tubing, conduit, etc.

If you don't believe me, please come by and tell me that those are NOT drops of water INSIDE my double pane windows, where the seal has broken. (and no, the water did not "run" in,l it came in a vapor).


EDIT:
This is something I know, (which is distinctly different from "I believe")

 

[phatboy48]

That's why you bring each end of the hose two or three feet above grade and bend the open ends back toward the ground to form inverted drip loops. This prevents rain water from entering. Don't seal the ends of the hose, leave them open. This reduces any condensation buildup over time. While this the idea may seem counter intuitive, it does work and has been used by others for years with success.

John

 

[N_Jay]

That's why you bring each end of the hose two or three feet above grade and bend the open ends back toward the ground to form inverted drip loops. This prevents rain water from entering. Don't seal the ends of the hose, leave them open. This reduces any condensation buildup over time. While this the idea may seem counter intuitive, it does work and has been used by others for years with success.

John

Unless you live in a very hot and dry place, I will bet you that after a year the low points are full of water.

There is no way you will get enough air flow to evaporate the water that condenses in the hose.

Even a few inches underground is MUCH cooler than above ground, and will easily condense any water vapor that gets in.

EDIT:
http://www.southwire.com/processGetArticle.do?commonId=0874b1e1a963d010VgnVCM1000002702a8c0____
http://www.selfhelpforums.com/showthread.php?t=6041
http://www.diychatroom.com/f18/driving-wire-through-buried-conduit-48228/index2/

 

[Thayne]

Ditto on the condensation; I have seen about a 100' run of properly installed PVC get so full of water in 1 yr that when we blew it out with a compressor the water shot 20 feet in the air for about about 2 minutes. Most kinds of wire for direct burial or wet locations has an extra sheath with "icky-pick" under the sheath and covering the inner sheath.
I am a fan of always using some sort of raceway rather than direct burial.

 

[ffemt601]

Try Davis RF Bury Flex ... its essentially direct bury lmr400.

 

[zz0468]

If you don't believe me, please come by and tell me that those are NOT drops of water INSIDE my double pane windows, where the seal has broken. (and no, the water did not "run" in,l it came in a vapor).

Which is exactly why waveguides and larger sizes of coax are pressurized with dehydrated air. But YOU *know* that already.

 

[AK9R]

Check out the Grounding Bulkhead Wiki and check out the links in the thread for more information on grounding and bonding.

For some reason, the URL for that wiki article didn't come through in your message, but I searched the wiki and found it.

Grounding Bulkhead with supressors for your scanning station - The RadioReference Wiki

 

[BuffaloJustice]

Thanks, I may have coded it wrong but it's not letting me edit the post. That was the first resource I read on bonding tower and radio equipment. We did spend a little time on bonding in network cabling class but it was more of a glance over and not much of an in depth explanation. It wasn't even brought up or checked in our big cabling project. It wasn't until the wiki that I started really studying it and understanding the how and why. I'm slowly updating our cable plant at work. I will say that a lot of the problems that have arisen over the years could have been solved with proper grounding and bonding. It got so bad I almost switched over to fiber optic between buildings but got shut down due to cost.

My shack is currently in "pull and pray" mode and I'm building up the grounding and bonding system before adding new radio goodies.

 

[N_Jay]

Which is exactly why waveguides and larger sizes of coax are pressurized with dehydrated air. But YOU *know* that already.

Dehydrated air or dry bottled gas

Of course most "radio" people don't know what any good HVAC person knows.

If you want to dry out a system, you have to vacuum it down!

 

[mikepdx]

RG-6 underground (direct burial).
Ask your local cable guy for a length of it.

Way back when I did cable TV installs, I was frequently asked for lengths of it
out on the street. People building new wanted to throw it in their open trench.
I never knew where the cable actually went. We gave 'em what they asked for.

At SW freqs - RG-6 will work just fine. Even at 60 ft.
Learning to put PL-259's on is the price for free cable. Use an RG-8X adapter.
The other repliers missed your point about pre-assembled connectors on the cable.
I doubt you'll find any direct burial cable with connectors pre-installed.
Although someone will probably do it for an arm and a leg.

LMR-400 ?? For Shortwave ??
C'mon, guys...

P.S. I'm dying to know what a "PAR connector box" is...

 

[eorange]

2. Which companies would provide this kind of cable at the lowest cost?

I would really recommend The RF Connection:

The RF Connection Home Page

I ordered 180 feet of direct burial Davis RG-8X cable from them last year. They are a great bunch of guys - like talking to friendly, knowledgeable hams in the back of the shop. I pretty much knew what I wanted, and they talked with me quite a bit anyway and answered all my questions. They will also add the connectors for you, for a small charge, and the cable was around the cheapest I've found.

FWIW, I had some RG-8 direct-buried for years, and buried the above cable last year. No conduit.

Good luck!