Base antenna grounding and lightning protection

[cryppie]

I am installing my first rooftop antenna and am looking for information concerning grounding and lightning protection. I usually find most information I need through google or other passive internet means... but I have ran into too much conflicting information concerning this topic.

So far, I have 75' LMR400 and an antenex Y8066 (6 element yagi). The antenna will be approximately 30' high connected to roof (maybe tripod, not sure yet). This will be used for receiving only, primarily with a UBC780XLT and a BC296D on occasion. My plan was to connect a copper wire (don't have yet) somewhere to the antenna and run it as direct as possible to a ground rod, already installed. That would be too easy... Now I am getting into lightning protectors and entrance panels . For the lightning protection, I am leaning towards a PolyPhaser IS-50 series, but that is an uneducated decision.

I would really appreciate someone to point me in the right direction for this project. Hopefully it will be easier than I have been led to believe.

Thank you,

cryppie

 

[jim202]

I find it hard to believe that you can't fine solid info on grounding your antenna
system. It has been covered on here many times.

1. Your house insurance will require that any antenna installed on the house be
grounded.

2. The National Electrical code requires that any antenna mounted on the house
be grounded. There are several sections that go into detail on how this is to be done.
In a simplified description, it boils down to the mast must be grounded with a wire run from the roof to a grounding electrode. If my memory serves me correct, I think they spell out the wire size as a minimum of #10. With my background coming from the two-way radio and cellular field, we ground everything with a minimum of #2 wire size. We also use exothermal welded connections for everything. The NEC does't go that far.

Most ham radio publications provide a number of ways to ground the antenna
system mounted to the house. You might want to go back and search some more on Google or Yahoo.

3. The Polyphaser surge protectors are a good selection. Problem is they don't
do much good without a good ground system. Note I am saying a good ground
system. This does not mean just driving in a ground rod and connecting the
polyphaser to it. Polyphaser has some good grounding information on grounding.

A grounding system takes in a number of different areas. It covers the antenna
support structure, the coax cable feedline, surge proyection on the coax cable,
making a common bond between the power line surge protecion the antenna
system the phone line surge protection and a good earth ring around the tower
and equipment shelter.

One of the long standing questions always asked it how do you know when you
have a good grounding system? A number of years ago this was defined by one
of the General Electric radio instructors by the definition of "You know when you
have made a good ground system when you can't afford to spend any more on it".

This may not be the answer your looking for, but with your question, this is about
the best your going to get.

Jim

I am installing my first rooftop antenna and am looking for
information concerning grounding and lightning protection. I usually find most
information I need through google or other passive internet means... but I have
ran into too much conflicting information concerning this topic.

So far, I have 75' LMR400 and an antenex Y8066 (6 element yagi). The antenna
will be approximately 30' high connected to roof (maybe tripod, not sure yet).
This will be used for receiving only, primarily with a UBC780XLT and a BC296D
on occasion. My plan was to connect a copper wire (don't have yet) somewhere
to the antenna and run it as direct as possible to a ground rod, already installed.
That would be too easy... Now I am getting into lightning protectors and entrance
panels . For the lightning protection, I am leaning towards a
PolyPhaser IS-50 series, but that is an uneducated decision.

I would really appreciate someone to point me in the right direction for this
project. Hopefully it will be easier than I have been led to believe.

Thank you,

cryppie

 

[cryppie]

Thank you for your reply Jim. If you notice, that was my first post in the 3.5 years I have been a member of RR.com (was previously a member of trunkedradio.net, but that was a few years ago) because of replies such as "use the search...etc". I appreciate the time you spent trying to help.

Do you have any links to the NEC or ham publications that spell out how to safely and correctly set up a ground/lightning protection. I will look at polyphaser.com again, maybe I missed something.

I realize there are many aspects to a grounding system, I just need all these aspects together in one place to get a good understanding.

Thanks again,

cryppie

 

[jack103]

Also make sure you tie all ground rods to the main grounding rod for the electrical service ground rod using at least a #8 awg conductor.

 

[cryppie]

If anyone is interested in this topic, a great writeup can be found at:

http://members.cox.net/pc-usa/station/grounding.htm

Thank you,

cryppie

 

[kb2vxa]

Hi Cryp and all,

OK, information overload, who to believe? I can tell you what the NEC requires, 6AWG copper minimum run straight as possible outside the structure without kinks or sharp bends from the supporting structure to a minimum of 8' copper clad steel earthing rod placed a minimum of 2' from the foundation wall. (I personally recomend multiple rods spaced about 12" and longer than minimum.) Connect all grounding points in the house together with 6AWG copper including the electrical entrance panel neutral bus. That means if you have additional earthing rods they must all be connected together. Add one earthing rod and yes, you have to connect it to the panel. This is to minimize potential between earthing points which can easily reach lethal voltage.

Likely you have state and county codes to contend with too, consult any state licensed electrical contractor. Conformance is mandatory, if you deviate and suffer damage your insurance is null and void.

One final note, everyone has opinions so who are you going to listen to, them or the law? I'll give you a hint, the NEC was drawn up by NFPA, the National Fire Prevention Association and I would rather go with the best fire chiefs and marshalls in the business and more years of collective experience than you can count.

 

[cryppie]

Great information, Warren. I see that you have also done your homework on this subject. Thank you for your help and time spent replying.

I have spent many hours this last week researching this subject, and have realized that there is not a quick instruction manual when it comes to lightning protection. It's not that easy. You really need to take the time to study the codes (there are many), learn the basic principles, and have a good understanding of how it all works together. I will emphasize "all works together" because if one minor detail is not done correctly, skipped, or forgotten, the whole system can and will probably fail, causing more damage than no grounding at all. This is usually the case when you hear "non-believers" talk about lightning damage that their uncles step-dad received with a "good" grounding system in place.

As of now I am scrounging up parts for my system. Here is a brief description of what I plan to do:

Install whole-house surge protector at service entrance.

Erect 30' or 40' mast beside house (better grounding than running copper from roof with multiple down conductors).

Bond coax at antenna to mast.

Bond coax at base of mast, just before the gradual 90 degree turn to house, to its own ground rod, bonded to the rest of the ground system.

Bond mast to three 10' x 5/8" copper ground rods, spaced 20' apart, starting about 3' from foundation, bonded together and to service entrance ground with 2" solid copper strap.

Bond grounds to water pipe.

Create an exterior single entry point for all cables coming into the house (sat, phone, antennas) using a copper plate, bonded to a ground rod directly below, then bonded to service ground.

Use a polyphaser on coax.

Create an interior ground block for coax, chassis, etc, bonded to outer plate.

Use good interior surge protection at equipment (I'm actually using an APC UPS battery backup plugged into a surge protector now)

And finally, bond the dog fence ground to ground system...

I will probably put up air terminals on the house grounded to individual ground rods, bonded to each other and the rest of the ground system. If I do, I will have a ground ring around house.

If you are planning a lightning protection system, please take the time to truly understand how it works. I have left out MANY small details (copper, connectors, the importance of bonding, etc) that are critical to the system. So critical that with all good intentions aside, the system will fail without a good understanding of how everything must work together.

I thank you again, Jim, Jack, and Warren, for your help.

cryppie

KC9DFG

 

[ssb_dxer]

Geez..............

I have spent many hours this last week researching this subject, and have realized that there is not a quick instruction manual when it comes to lightning protection. It's not that easy.




Very simple. Un-Plug your outside antenna coax from your radio during thunderstorms. If you want to listen during storms, hook up an indoor antenna. What is so hard about that???

 

[OpSec]

I have spent many hours this last week researching this subject, and have realized that there is not a quick instruction manual when it comes to lightning protection. It's not that easy.




Very simple. Un-Plug your outside antenna coax from your radio during thunderstorms. If you want to listen during storms, hook up an indoor antenna. What is so hard about that???

Not so simple. Sure you can unplug the outdoor antenna, but if it's not grounded then you still are avoiding the basic problem.

 

[ka3jjz]

If anyone is interested in this topic, a great writeup can be found at:

http://members.cox.net/pc-usa/station/grounding.htm

Thank you,

cryppie

Sadly, it's a dead link 73 Mike

 

[rfradioconsult]

I would not connect to your cold water system, you may create a very small DC current from your radio equipment that could cause Galvanic action and over time cause your water pipes may erode and start leaking.

Most folck think that proper protection is a quick and inexpensive fix, as your research confirms it is neither quick or cheap and still does not insure that your equipment or your home would survive a direct strike. A Billion volts at a couple of hundred thousand amps can do a lot of damage in the blink of an eye.

Any Communications professional will tell you that to properly protect a comm site is one of the most costly items involved if it's done correctly.

 

[pstox]

Great information, Warren. I see that you have also done your homework on this subject. Thank you for your help and time spent replying.

I have spent many hours this last week researching this subject, and have realized that there is not a quick instruction manual when it comes to lightning protection. It's not that easy. You really need to take the time to study the codes (there are many), learn the basic principles, and have a good understanding of how it all works together. I will emphasize "all works together" because if one minor detail is not done correctly, skipped, or forgotten, the whole system can and will probably fail, causing more damage than no grounding at all. This is usually the case when you hear "non-believers" talk about lightning damage that their uncles step-dad received with a "good" grounding system in place.

As of now I am scrounging up parts for my system. Here is a brief description of what I plan to do:

Install whole-house surge protector at service entrance.

Erect 30' or 40' mast beside house (better grounding than running copper from roof with multiple down conductors).

Bond coax at antenna to mast.

Bond coax at base of mast, just before the gradual 90 degree turn to house, to its own ground rod, bonded to the rest of the ground system.

Bond mast to three 10' x 5/8" copper ground rods, spaced 20' apart, starting about 3' from foundation, bonded together and to service entrance ground with 2" solid copper strap.

Bond grounds to water pipe.

Create an exterior single entry point for all cables coming into the house (sat, phone, antennas) using a copper plate, bonded to a ground rod directly below, then bonded to service ground.

Use a polyphaser on coax.

Create an interior ground block for coax, chassis, etc, bonded to outer plate.

Use good interior surge protection at equipment (I'm actually using an APC UPS battery backup plugged into a surge protector now)

And finally, bond the dog fence ground to ground system...

I will probably put up air terminals on the house grounded to individual ground rods, bonded to each other and the rest of the ground system. If I do, I will have a ground ring around house.

If you are planning a lightning protection system, please take the time to truly understand how it works. I have left out MANY small details (copper, connectors, the importance of bonding, etc) that are critical to the system. So critical that with all good intentions aside, the system will fail without a good understanding of how everything must work together.

I thank you again, Jim, Jack, and Warren, for your help.

cryppie

KC9DFG

cryppie seems to know what he is talking about. Does anyone have a working link for the information he had posted or does this pretty much cover it?