help me ground properly

[jetscanner]

I just recently put up a 30ft mast of metal conduit with a j-pole antenna. The antenna is going to be used for scanning only.

I have the mast attached via strong hose clamps to an OLD 5' pole that was concreted in and used for a direcway installation. Right next to it is a ground rod for the OLD installation, as well as the copper wire.

We do get lightning around here, and I'd sleep much better knowing its properly grounded. I have a simple "copper wire touching mast - wire touching ground rod" setup right now, but not sure thats good enough.

I'm also aware I need to ground the coax.

Any tips? advice?

 

[azlooker]

Howdy! Here is what I would do. Run a piece of 2 gauge wire from the base of the 30 foot pipe to the ground rod using the existing clamp or get the proper one if it is missing. On the pole, you can use another hose clamp and scrape an area of the pipe bare but I suggest you drill a hole through the pipe, use a nut and bolt and outside teeth star washers on both sides of the pipe, and bolt it tightly to the pipe. Again, scrape the area under the lug bare to get the best mechanical connection. I normally use battery cable's with lugs already attached if the run is not very long. The coax presents a little more complexity. I use a lot of Polyphaser brand units. To be effective though you need a good ground available near the equipment you want to protect. To some, this may be overkill, but I have seen a lot of lightning destroy expensive equipment because of being cheap with protection. One other thing, do not overlook providing some level of protection on the AC power side. You do not say what kind of radio you are using, whether it is a base, mobile on a power supply, or a portable. But with scanners costing upwards of $500-600 nowadays, spending $75 for protection is a good investment.

 

[hoser147]

Welcome to RR, Check the Wiki for more info, there is a link at the top of the page.Lots of good info there. Hoser

 

[jetscanner]

Thanks guys.

Not long after I posted this, I went outside and basically did what azlooker suggested.

The bottom of the wire is now firmly screwed into the top of the ground rod, and I placed the top of the copper wire tight under a hose clamp i'm already using. On both ends the copper wire has about 2-3 inches of contact and the copper wire is as straight as possible (as ive read is needed)

Now just for the coax. I may add a ground block to the mast and connect it to the ground rod (like the satellite setup was) or run the coax across and attach it to a groundblock thats already on the house.

Any objections to either?

I *believe* I read somewhere that its best to ground all to the same location.

 

[KC0QNB]

Thanks guys.

Not long after I posted this, I went outside and basically did what azlooker suggested.

The bottom of the wire is now firmly screwed into the top of the ground rod, and I placed the top of the copper wire tight under a hose clamp i'm already using. On both ends the copper wire has about 2-3 inches of contact and the copper wire is as straight as possible (as ive read is needed)

Now just for the coax. I may add a ground block to the mast and connect it to the ground rod (like the satellite setup was) or run the coax across and attach it to a groundblock thats already on the house.

Any objections to either?

I *believe* I read somewhere that its best to ground all to the same location.

All systems should be grounded be it electrical or radio, it is recommended to use a single point ground and everything should be bonded. I posted a thread in the antenna forum, about a month ago, it is here, in the thread references were made to websites for more information, lust click the links. You can also just google for, antenna grounding, proper antenna grounding, and find the same stuff and much more. Welcome to RR

 

[jetscanner]

All systems should be grounded be it electrical or radio, it is recommended to use a single point ground and everything should be bonded. I posted a thread in the antenna forum, about a month ago, it is here, in the thread references were made to websites for more information, lust click the links. You can also just google for, antenna grounding, proper antenna grounding, and find the same stuff and much more. Welcome to RR

Yeah I came across that post during my research and read a bit before I posted. If the answers in there, forgive me, im a diagram junkie who gets headaches when he reads too much.

Most of the stuff I had come up with as far as google etc. (prior to this post) looked pretty hardcore. (ex: 4+ 8' ground rod setups etc) usually followed by an explanation of how everything inside the universe works.

 

[KC0QNB]

Two things you can never get enough of is the universe and proper grounding.
I was talking to one of our contractor/customers a few days ago, it seems that grounding things is becoming a trade all its own, in order for a licensed electrician to get enough grounding education, it will take 12 years worth of "continuing education" classes to become proficient at it. Personally I have seen the grounding section in the NEC, in particular antenna systems going from a few pages in the 1996 code to many pages in the 2008 version,which I don't have a hard copy of yet. Google article 800 NEC, you will find a lot of stuff, up to and including how the universe works :wink:. Good luck in your research.

 

[jetscanner]

Two things you can never get enough of is the universe and proper grounding.
I was talking to one of our contractor/customers a few days ago, it seems that grounding things is becoming a trade all its own, in order for a licensed electrician to get enough grounding education, it will take 12 years worth of "continuing education" classes to become proficient at it. Personally I have seen the grounding section in the NEC, in particular antenna systems going from a few pages in the 1996 code to many pages in the 2008 version,which I don't have a hard copy of yet. Google article 800 NEC, you will find a lot of stuff, up to and including how the universe works :wink:. Good luck in your research.

Ugh, ive came across the "code" pages, too much!!!

and I see you have an old pro-46 thats never failed eh? I have a pro-51, good little scanner.

My oldest is a Sony Air-8 "Airband".........Time and travel tested. Frankly, im not sure itll ever stop working.

 

[KC0QNB]

Then the minimum grounding system would be the way to go, 1) 8 foot ground rod at the base of the mast, with two ground wires one from the antenna mount bolts at the top of the mast ran to its own ground clamp on the ground rod, another at the base of the mast with also ran to its own ground rod clamp, and you can use a pipe grounding clamp around the mast it the mast is painted you will need to remove the paint where you want the clamp, if the mast if galvanized just make it shiny, don't get carried away. now you will need a #6 or #4 solid copper wire also on its own ground rod clamp attached to the mast ground rod, run that over to the electrical service ground, if it is going to be a trip hazard bury it a few inches and attach it to the electrical service ground rod or existing ground wire (not as good) if you use the electrical service ground rod it needs its own ground rod clamp there also. You will need to tie in an antenna discharge device also.
The pro 46 was made my Uniden and I believe the 51 was made by GRE, the 46 is quite small in comparison, still big by todays standards however.

 

[jetscanner]

two more questions.

#1. My coax comes from my antenna, which is clamped to a properly grounded mast. Do I still need to ground the coax?

#2. If I plugin my scanner to an outlet (instead of using batteries), does this count as grounding the coax?

 

[OceanaRadio]

two more questions.

#1. My coax comes from my antenna, which is clamped to a properly grounded mast. Do I still need to ground the coax?

#2. If I plugin my scanner to an outlet (instead of using batteries), does this count as grounding the coax?

1. Assuming you mean you have shield-grounded the coax at the base of the mast, that is the first of two shield-grounds (at a minimum) you require. The other is at the home-entry point prior to the radio.

2. Oh yes you are sure grounding the coax when you plug a radio into the AC outlet, and providing a path in the worst possible way! That path represents the intersection of two vastly differing electrical potentials, one from the AC/house side and the other from the antenna/mast side. Destruction of the radio is assured from an insult arriving in either direction.

This is the reason you must bond the mast grounding to the AC entrance ground of the home.

If a long distance from the mast ground to the AC entrance you can never acheive the desired equipotential between them, but you will minimize the potential difference, and that is a must-do.

Then, a coax surge arrestor installed before the radio, and an AC surge arrestor installed at the AC-Mains panel or meter completes the protection concept. Equipotential is maintained on both systems and both systems have line protection from surges arriving in either direction.

Most hobbyists do not add the AC entrance surge protection. This puzzles me because you are protecting your entire home, all your applicances, stereos, tv's etc when you make that investment. Adding little power-strip surge protection at each appliance, device etc is ok but only a band-aid if it is your only protection. Damage to homes via the power lines from nearby lightning is the #1 cause of insurance claims resulting from lightning. You compound the situation when you add a remote coax entry point to the home that is also connected to a remote ground and remote source of lightning energy. Hence the NEC/NFPA and common sense reasons to bond the two together.

Where you live is a big factor in making the decision to add lighting protection, and how much.
Replacement-value insurance is the other side of the coin, and it is expensive.

Jack

 

[jetscanner]

1. Assuming you mean you have shield-grounded the coax at the base of the mast, that is the first of two shield-grounds (at a minimum) you require. The other is at the home-entry point prior to the radio.

2. Oh yes you are sure grounding the coax when you plug a radio into the AC outlet, and providing a path in the worst possible way! That path represents the intersection of two vastly differing electrical potentials, one from the AC/house side and the other from the antenna/mast side. Destruction of the radio is assured from an insult arriving in either direction.

This is the reason you must bond the mast grounding to the AC entrance ground of the home.

If a long distance from the mast ground to the AC entrance you can never acheive the desired equipotential between them, but you will minimize the potential difference, and that is a must-do.

Then, a coax surge arrestor installed before the radio, and an AC surge arrestor installed at the AC-Mains panel or meter completes the protection concept. Equipotential is maintained on both systems and both systems have line protection from surges arriving in either direction.

Most hobbyists do not add the AC entrance surge protection. This puzzles me because you are protecting your entire home, all your applicances, stereos, tv's etc when you make that investment. Adding little power-strip surge protection at each appliance, device etc is ok but only a band-aid if it is your only protection. Damage to homes via the power lines from nearby lightning is the #1 cause of insurance claims resulting from lightning. You compound the situation when you add a remote coax entry point to the home that is also connected to a remote ground and remote source of lightning energy. Hence the NEC/NFPA and common sense reasons to bond the two together.

Where you live is a big factor in making the decision to add lighting protection, and how much.
Replacement-value insurance is the other side of the coin, and it is expensive.

Jack

As it is, the mast/antena is grounded to a ground rod in the ground. However, the coax has no protection. It goes straight from the antenna connection to my radio.

Is there any way I can avoid a ground block with the coax?

Honestly, im trying to avoid having to cut the wire to throw in a ground block. Unless you know of a way to properly cut coax and add connectors without any compression/coax tools, etc. Just having a hard time spending the $$ on tools and parts for one time use to protect a fairly old radio.

You mentioned a coax surge arrestor. Can these be considered a replacement to a ground block? Or are they just for additional protection?

 

[OceanaRadio]

As it is, the mast/antena is grounded to a ground rod in the ground. However, the coax has no protection. It goes straight from the antenna connection to my radio.

Is there any way I can avoid a ground block with the coax?

Honestly, im trying to avoid having to cut the wire to throw in a ground block. Unless you know of a way to properly cut coax and add connectors without any compression/coax tools, etc. Just having a hard time spending the $$ on tools and parts for one time use to protect a fairly old radio.

You mentioned a coax surge arrestor. Can these be considered a replacement to a ground block? Or are they just for additional protection?

You can expose the outer braid (or solid foil, depending on coax type), clamp copper tape to that, completely weatherize the connection, and use that as your shield ground to a ground rod. All professional installations expose the outer braid and affix shield-ground kits to the coax in that fashion. An arrestor connects in-line with coax further downstream, but does require you have a coax connector for it on each of its input and output sides. Yes an arrestor does by default "shield ground" the coax BUT there can be failures when there is no upstream coax shield ground, such as at your mast-base.

Even if you don't care about the radio involved, you should be mindful of the risk associated with causing or allowing two systems of greatly differing potential to exist inside your home. Other than what I consider both the dangerous and unreliable method of "disconnecting before a storm", I know of no other way to operate safely than to make the installation proper IAW code and best practice. If you aren't willing to make a good assessment and plan for the risks, then you can always put an antenna inside your attic and avoid all this concern. It's the old "walk on left side, ok, walk on right side, ok, walk in middle, hit by truck".

Jack

 

[stevolene]

Then the minimum grounding system would be the way to go, 1) 8 foot ground rod at the base of the mast, with two ground wires one from the antenna mount bolts at the top of the mast ran to its own ground clamp on the ground rod, another at the base of the mast with also ran to its own ground rod clamp, and you can use a pipe grounding clamp around the mast it the mast is painted you will need to remove the paint where you want the clamp, if the mast if galvanized just make it shiny, don't get carried away. now you will need a #6 or #4 solid copper wire also on its own ground rod clamp attached to the mast ground rod, run that over to the electrical service ground, if it is going to be a trip hazard bury it a few inches and attach it to the electrical service ground rod or existing ground wire (not as good) if you use the electrical service ground rod it needs its own ground rod clamp there also. You will need to tie in an antenna discharge device also.
The pro 46 was made my Uniden and I believe the 51 was made by GRE, the 46 is quite small in comparison, still big by todays standards however.

when you say service entrance, are you speaking of where the electrical meter is at the structure?