Advice on grounding for Outdoor Antenna #antennas


 

So the last of the parts needed for moving the antenna from the attic to outside are arriving tomorrow afternoon. I'm planning on getting everything done Friday and part of Saturday if needed. I do have a couple questions that I would like to get input from more experienced individuals. 

I installed an enclosure outside where the antenna feed will go into the arrestor and from there in to the house to my ham shack. From that specific location, it will be a 38ft run of grounding cable to tap into my house utility grounding rod. 
I bought 6 AWG solid copper grounding cable to ground the antenna arrestor to my house grounding rod. 

My question is if the 38ft length I would have to run is to long and if I should install a grounding rod at the enclosure I installed?

I do understand that if I put a new grounding rod at the new enclosure, I would have to bond both grounding rods together. I just don't know if I need to do it or if that length is good and I can save my self the cost of the additional parts and tool rental to get a grounding rod installed. 

If I have to do it, then I have no problem doing it. Just want to make sure. 

Thank you all in advance. Any other suggestion or tips are always welcomed!

Carlos
KO4JNY


N9MVF-Ken
 

Hey Carlos.. I recommend you install a ground rod at the entry point, and run the bonding wire, yes.  The bonding wire can actually be smaller than 6ga (my opinion, others may differ), as all it is doing is balancing the voltage differences.  More grounding rods don't hurt, ever.. :)  So, capital-H 'Have' to, I mean, for arguments sake, maybe not.. 'Have' to.. but Should you?  I suggest you should. 

I have a hitachi hammer drill and a 3 ft masonry bit if you need to drill through some rock or something that you're welcome to borrow, by the way. 

-Ken, N9MVF



On Wed, Jan 13, 2021 at 12:38 PM Carlos KO4JNY <vazquezusmc@...> wrote:
So the last of the parts needed for moving the antenna from the attic to outside are arriving tomorrow afternoon. I'm planning on getting everything done Friday and part of Saturday if needed. I do have a couple questions that I would like to get input from more experienced individuals. 

I installed an enclosure outside where the antenna feed will go into the arrestor and from there in to the house to my ham shack. From that specific location, it will be a 38ft run of grounding cable to tap into my house utility grounding rod. 
I bought 6 AWG solid copper grounding cable to ground the antenna arrestor to my house grounding rod. 

My question is if the 38ft length I would have to run is to long and if I should install a grounding rod at the enclosure I installed?

I do understand that if I put a new grounding rod at the new enclosure, I would have to bond both grounding rods together. I just don't know if I need to do it or if that length is good and I can save my self the cost of the additional parts and tool rental to get a grounding rod installed. 

If I have to do it, then I have no problem doing it. Just want to make sure. 

Thank you all in advance. Any other suggestion or tips are always welcomed!

Carlos
KO4JNY


W4TFZ Carey
 

Carlos, At a bare minimum, yes you have to have a ground rod at the base of the mast/tower per the National Electric Code, and bond it back to the main ground of the house. And bond your mast to the ground rod at the base if its metal. #6 is the minimum per the NEC. I always prefer #4 or #2 myself. You may not find the top of your ground rod at the main ground location. Depending on the age of your house you may (should) have a intersystem bond on the wire going down to that main ground rod. It might look like a small ground bar, with or without a plastic cover, or it may look like a fitting about 3inches long coming out of the bottom of you main disconnect with a piece of pvc going into it that has some green screws in it. This is where the phone company and cable company will add their ground wires to. You can bond you second ground to this. As long as you are bonded back to the main ground you can you can run a ground wire from the lighting arrestor over to the ground rod at the base of the mast. OH, and don't forget to run a braided ground from your equipment out to that ground rod at the mast too also to avoid a ground loop. 

The details of the NEC actually tells you that you should install a grounding grid out from the base, with ground rods no closer than 8 feet separation and the bare copper & rods buried completely. Technically if you can't install a ground rod straight down you are allowed up to a 45 degree angle pointed away from the structure. Here in TN with as much rock as we have it is not uncommon for electricians to dig a deep trench and lay the ground rod in the bottom of the trench to be sure that all 8 ft are buried as required by the NEC. 

Since my mast is attached to the end of my house I have a V shaped grid going out from the base, and the ground rod there, 90 deg apart the with rods at 8 & 16 ft out from the base of the mast with #2 hard drawn copper buried about 10 -12 inches down. (I chose the hard drawn since I have access to it, normal people would probably just use soft drawn) Yes mine is way over the requirements but I have a lot of lightning in my area so I wanted to be sure if I took a strike it would be directed away from the house. My vertical is higher than the power poles in the area so I'm overly cautious. In fact I just realized that my wire antennae for HF is pretty close to that height too.

One other thing to point out is that the "enclosure" you have installed, appears to be an AC disconnect, or similar, that has been gutted out. If you are running LMR400 you will find that it probably will not give you enough wire bending space to install the lighting arrestor. The lighting arrestor and connectors add up to be longer than you think. I did that using a 6x6x4 PVC J-Box and discovered it was too small. I still have wires hanging all over the place outside until I go get the box to clean up my install. I just haven't gone into town to pick up an 8x8 or 12x12 yet since I'm working from home. Be sure to check the minimum bend radius for the coax that you are using, and add up all of the items together to determine how much space that you need. Times Microwave specs for LMR400 says a minimum of 4 inch bend radius for flex applications, and one inch if it is a permanent stationary install, such as on the back of your rig. This is to avoid crushing the dielectric which could have adverse effects on your SWR and communications ability.

There is about a 10(?) page post / "argument" in the forums at QRZ about grounding if you are interested. It actually does have some good points that you can learn from. DISCLAIMER: In MY OPINION some of the points in that thread you may have to take with a grain of salt because there are some antagonists who have obviously never worked in the field, and are basing all of their arguments on theory, not on practical application, or even parts that are actually made. Remember its the internet and what may be OK in other countries may not be OK here.


 

Thank you both for your responses it was exactly the advice I was looking for !! 

I am going to go ahead and install the ground rod and all the required connections. 

Ken- thank you for the offer on lending me the tools. My neighbor actually has one and I will be borrowing, but I really do appreciate it. 


Carey- thanks for the detailed response. You actually answered more questions I had. Specifically about attaching the bonding grounding wire to the wire sticking out of my utility grounding rod. I see where your talking about because I was able to find the grounding attachments for my cable and internet services. I added some more pictures of the way I’m installing the antenna. I’m installing a bracket on the eve or fascia of the back side of the house as high as I can reach. The antenna will be physically installed on a j pipe mount which then attaches to the bracket previously mentioned. Based on what you responded earlier. This would have to be grounded to the grounding rod I’m installing correct? 

I do see what your talking about as well in regards to the enclosure. I was worried about that. I’ll probably just go ahead and pick a bigger one to avoid any issues. I am using LMR-400 and from my limited experience I can see it being an issue with limited space and the bending radius. I didn’t know how big the arrestor  would be and I already had that enclosure from a different project I was working on. 


Anyways thank you both again !! 


 

just finished adding the ground rod and bonding it to my utility grounding rod. Got a bigger enclosure as well I think it should be big enough  it’s an 8x8x4. 

It was actually a lot easier than I was anticipating. 


thank you both again !