I think I finally have a plan for base station

[ClemsonSCJ]

I’ve been posting on here and some other places over the past couple months trying to get an idea of how I should set up my base station. After doing a lot of reading and research on grounding and other topics, I think I finally have an idea of how I’m gonna set it up (this is for VHF/UHF dual band and soon down the road a cb base as well):

My antenna mast(s) will mounted at my chimney. Not TO the chimney, they will just be mounted right next to it. I’m going to mount an entry panel on the back side of the chimney, not for entry, but just to weatherproof the lightning arresters and ground bus. Inside the box will be 2 lighting arresters mounted to a copper bus. I’m going to have a 6awg thhn wire running from the base of the antenna (or as close to it as I can get) and into the entry panel box, through the ground lug attached to the bus bar. This will continue out of the entry panel and straight to ground. To paint a picture, the ground wire will go straight from the mast to ground, but will pass through the lug attached to the lightning arrester bus thereby allowing for only one ground wire run for both the mast and lighting arresters. Again, this will all be at the base of the chimney where it meets the roof. The coax will then leave the entry panel and enter the attic space at the peak of the roof through the ridge vent. I will then bring the coax into the shack through the ceiling from the attic space. I will have another bus bar in the shack for all the radio equipment which will have another 6 awg thhn wire running down through the floor into the crawl space, and out of the crawl space to the same grounding point as the antenna mast.

I have discovered that my house has an ufer ground system and no grounding rod, so the mast bus and station bus will both be connected to the 6awg bare copper wire that runs from the main power meter to ground by a split bolt. So all in all, does this sound like a relatively safe setup and to code, or does it sound like I’m gonna burn my house down and potentially electrocute myself in the process?

 

[a417]

<snip> I’m going to have a 6awg thhn <snip>

can you use THHN outdoors? doesn't it need to be THWN even tho it's in a ground capacity?

 

[ClemsonSCJ]

can you use THHN outdoors? doesn't it need to be THWN even tho it's in a ground capacity?

Hell I’m gonna be honest man...I had never heard of THWN before your post so that I guess I’ll have to change. Thanks for the input.

 

[DS506]

This will continue out of the entry panel and straight to ground.

Does that satisfy grounding the mast AND bonding that ground to the service ground?

 

[mmckenna]

You want the protectors at the point the coax enters your home. Not sure if that's what you have in mind.

Ideally you want the mast straight to ground with no unnecessary joints. Run one ground wire straight down from the mast to the ground rod.
Run a second ground wire from your ground buss straight down to the ground rod.
Use separate clamps for each ground wire.

Other than that, sounds like you've got a good plan. Doing commercial like installs in residential buildings is a real pain in the butt. They just are not designed for this sort of stuff.

 

[ClemsonSCJ]

Does that satisfy grounding the mast AND bonding that ground to the service ground?

The mast will have a ground clamp attached to it and a 6awg wire run straight from it to the service ground. The entry panel containing my lightning arrester bus is being mounted in line with that so that the mast ground line runs through the top of that entry panel, through the ground lug and continues out the bottom of the entry panel to the service ground. So that at that point that mast ground like also becomes my lightning arrester ground like and both are grounded to the service ground. Hope that makes sense.

 

[jonwienke]

Ideally you want a dedicated ground rod directly below the antenna at the bottom of the mast, and then bond that to your antenna and your utility service ground by the shortest paths using 6ga or heavier wire.

 

[ClemsonSCJ]

You want the protectors at the point the coax enters your home. Not sure if that's what you have in mind.

Ideally you want the mast straight to ground with no unnecessary joints. Run one ground wire straight down from the mast to the ground rod.
Run a second ground wire from your ground buss straight down to the ground rod.
Use separate clamps for each ground wire.

Other than that, sounds like you've got a good plan. Doing commercial like installs in residential buildings is a real pain in the butt. They just are not designed for this sort of stuff.

It’s going to work out to where I can enter the coax through the ridge vents at the apex of the roof, which will be about a foot at most from where the entry box will be. They entry panel will be merely for weatherproofing, and not for actual entry.

As for the mast ground line, I may not have painted the correct picture. The mast ground like will run straight down from the mast to the utility ground. It will run though the entry panel and through a ground lug that will basically also provide a grounding like for the bus. But the line for the mast itself will be uninterrupted. That may still be non-ideal and what you pictured, I just wanted to make sure you didn’t think I was attaching the mast to the ground bus, and then a second line running from the bus to ground.

 

[ClemsonSCJ]

Ideally you want a dedicated ground rod directly below the antenna at the bottom of the mast, and then bond that to your antenna and your utility service ground by the shortest paths using 6ga or heavier wire.

Yeah I did a whole lot of reading in the ARRL grounding and bonding book as well as a bunch of other sources through forums and what not in preparation for that very plan. I finally got my head around how to drop a new ground rod and tie it to the other ground rods properly and within code.

Then I found out that my house has an ufer ground rather than ground rods and I can’t find anything on how to add ground rods to an ufer ground system and properly bond the 2. So this is the best system I’ve come up with.

 

[mmckenna]

It’s going to work out to where I can enter the coax through the ridge vents at the apex of the roof, which will be about a foot at most from where the entry box will be. They entry panel will be merely for weatherproofing, and not for actual entry.

Good deal, sounds like a really good setup.

As for the mast ground line, I may not have painted the correct picture. The mast ground like will run straight down from the mast to the utility ground. It will run though the entry panel and through a ground lug that will basically also provide a grounding like for the bus. But the line for the mast itself will be uninterrupted. That may still be non-ideal and what you pictured, I just wanted to make sure you didn’t think I was attaching the mast to the ground bus, and then a second line running from the bus to ground.

So, while all the grounds will be connected, eventually, you probably don't want to run the mast ground through the ground buss. You want a straight uninterrupted run down to the rod. Idea is that you want to get any energy to the ground rod (and just the ground rod) as quickly and direct as possible.

 

[ClemsonSCJ]

Good deal, sounds like a really good setup.



So, while all the grounds will be connected, eventually, you probably don't want to run the mast ground through the ground buss. You want a straight uninterrupted run down to the rod. Idea is that you want to get any energy to the ground rod (and just the ground rod) as quickly and direct as possible.

That makes sense and honestly shouldn’t throw much of a kink in the plan. Will just require buying double the length of wire and honestly that’s the only reason I was doing it, to cut down on wire runs but it’s not just about a 25ft run anyways.

 

[WB9YBM]

My antenna mast(s) will mounted at my chimney. Not TO the chimney, they will just be mounted right next to it.

I have a similar situation here; even though I've not noticed the following problem myself (maybe we just have a clean furnace), I've had people mention tom me that some of the gasses coming out of a chimney can have some bad effects on metal & connections/solder....

 

[chief21]

The coax will then leave the entry panel and enter the attic space at the peak of the roof through the ridge vent. I will then bring the coax into the shack through the ceiling from the attic space.

From your description, it sounds as if the coax between the grounding panel at the chimney and the actual entry point to the attic might be vulnerable to an unprotected surge. The purpose of the lightning suppressor is to shunt any surge to ground. If there is a section of unprotected coax remaining outside, downstream of the suppressors, that could be problematic... especially if that coax is higher (ridge vent = highest point?). Would it be better to enter the attic via the soffit, rather than the ridge vent?

 

[jonwienke]

As for the mast ground line, I may not have painted the correct picture. The mast ground like will run straight down from the mast to the utility ground.

Unless the utility ground rod is already at the base of the mast, no. Add a new ground rod at the base of the mast, and run 6ga or heavier wire straight down from the antenna to the new ground rod at the base of tbe mast, to give lightning a straight path direct to ground. Then run a separate 6ga or heavier wire from the mast ground rod to your utility power ground to ensure they stay at the same potential, and you don't have voltages between your radio chassis and anything else.

 

[ClemsonSCJ]

Unless the utility ground rod is already at the base of the mast, no. Add a new ground rod at the base of the mast, and run 6ga or heavier wire straight down from the antenna to the new ground rod at the base of tbe mast, to give lightning a straight path direct to ground. Then run a separate 6ga or heavier wire from the mast ground rod to your utility power ground to ensure they stay at the same potential, and you don't have voltages between your radio chassis and anything else.

If I put a ground rod at the base of my mast, I’ll have a hole in my roof and a random rod sticking in the attic space.

From where the mast is being mounted on the roof, the utility ground is the most direct path to ground. There is nowhere I could drop a ground rod that would be a closer and more direct path. The main utility line is against the back of the house right below where the mast will be.

 

[jonwienke]

You said earlier you didn't have a utility ground rod. If there is a ground rod directly below the antenna, tie to that. If not, put a new ground rod in the ground as directly below the antenna as possible, and connect it to the antenna with the shortest and straightest run possible without running wires inside the house.

 

[ClemsonSCJ]

You said earlier you didn't have a utility ground rod. If there is a ground rod directly below the antenna, tie to that. If not, put a new ground rod in the ground as directly below the antenna as possible, and connect it to the antenna with the shortest and straightest run possible without running wires inside the house.

There’s not a ground rod, but there is a utility ground. It’s an ufer ground. So everything is tied to the foundation by 6awg bare copper wires. So why wouldn’t I just clamp my mast ground to that rather than putting another ground rod right next to it?

 

[jonwienke]

If the rebar or whatever the ufer ground uses for its connection point is directly below the antenna, then connect to it as if it was a ground rod, just like the utility power does.

If not, you need to install a separate ground rod or ufer ground (whichever is required by local code) directly below the antenna, and then have separate wire runs going to the antenna and utility ground.

 

[ClemsonSCJ]

If the rebar or whatever the ufer ground uses for its connection point is directly below the antenna, then connect to it as if it was a ground rod, just like the utility power does.

If not, you need to install a separate ground rod or ufer ground (whichever is required by local code) directly below the antenna, and then have separate wire runs going to the antenna and utility ground.

An ufer ground is in the foundation of the house. The isn’t any rebar that comes out of the ground. The 6awg copper wires run underground and connect directly to the foundation. So the 6awg wire coming out of the ground and connecting to main utility is all I got.

 

[ClemsonSCJ]

From your description, it sounds as if the coax between the grounding panel at the chimney and the actual entry point to the attic might be vulnerable to an unprotected surge. The purpose of the lightning suppressor is to shunt any surge to ground. If there is a section of unprotected coax remaining outside, downstream of the suppressors, that could be problematic... especially if that coax is higher (ridge vent = highest point?). Would it be better to enter the attic via the soffit, rather than the ridge vent?

The main purpose of going in at the ridge vent was to cut down on cost and dB loss from running excess coax down the roof instead of just going in at the peak of the roof...so all that being said, yes I could do that. But if I do I would have to mount the entry panel to the wall below the soffit and then have the coax come out of the entry panel to enter the soffit. Would that not create the same problem?