Ground Strap/Flashing - Logistical Questions

[KB4MB]

Ok, so I am tired of being told that I must use flashing for my station for its' ground, so here is my situtation and see if you can tell me how to do this.

I have a ground bar at the desk, and I will be using copper braid for the connects to the bar using hose clamps (I want it to be flexible and not cut me or my cables up - largest run is 1'). First problem: From the bar to the service ground (outside, three feet away), can I run a heavy wire, or will I screw up my rf ground by doing that? I think the XYL would kill me if there was a sheet of copper running out a window, visible to all; a wire I can hide with the other wires poking out of the house.

From the service ground out two the two additional ground rods I have, I can run the flashing (3" wide enough?), but then, how to attach to the ground rods? Can I use jumper wires and split bolts?

How far down does the flashing need to be buried.... is 1/2" ok? The ground is super tough here lately, and I have a horse farm and loads of manure/compost, so I was thinking of just rebedding that area anyway and adding soil instead of digging...

Right now, I run a skywire loop fed with twinlead, but I am curious to see if an RF ground will help improve anything (I assume not at all, but still curious). Maybe one day I will put up an inverted L, so I figure try to run a ground now. The second rod is where the antenna feed line comes down (right in the middle of the layout), and I will get one of those sparkplug arrestors, just for shiggles. We do get lightning around here, and it has hit my pastures before. The third ground rod is where I figure I would put an L one day, and have left the rod above the surface a bit to attach radials if I want/need to.

Thanks in advance for any advice,
Kris, KB4MB

[K3STX]

I'm no expert, but I think thick WIRE is all you need to go from your copper ground bar (in your shack) out to a ground rod. This same ground rod should be connected directly by thick wire to your electrical mains ground. That is all you need. If you want additional ground rods (I have 4 total) just have them all hooked up to that same electrical mains ground: mine are all "in series" I use #8 wire, solid is best. As fat as you can get.

I think you misunderstood the flashing thing. I have a strip of aluminum flashing along the wall behind my bench that all equipment ties into, then this aluminum flashing is hooked to a 4 foot long wire to go outside to the ground rod. I don't think anyone ever intended you to run flashing from inside to outside your house!

The way you are doing it is better than 90% of Hams. Most people hook all their equipment "daisy chain" from one piece of gear to another; that is BAD news! They should EACH go the pipe/flashing.

You got it, get some wire, the fatter the better. And I seem to remember reading that copper braid (like off old coax) is not nearly as good as fat solid wire, maybe an expert can correct me if I am wrong.

paul

[KB1NXE]

Kris,

In all honesty, yes, you can do it the way you propose. I know I and others have recommended the 'best practice' to you. All that gets confusing, cuz everyone has their opinion on how to do it.

Go to the PolyPhaser site and under support there's a wealth of documents that will help you learn about grounding. You take all that knowledge and adjust it to fit your situation. No one here knows the variables of your house, your lightning strike potential or your architectural requirements.

Anything is better than nothing.

To answer your specific questions: The ground from your rigs to earth is more of a safety/lightning ground than an RF ground. RF Grounds can be easily described as the radial field under a Vertical antenna and provide a return path for RF. What you're working for is a path for any induced currents to ground from a near strike or a strike that enters your house via a different path than your antenna leads. It also helps any stray RF currents find a home in terra firma if they end up induced on the chassis of your radios. Counting on the 3rd prong is NOT a good idea as not all you devices will be connected electrically to it (how many 12VDC power supplied do you think have the negative lead bonded to the supplies chassis?).

The 3" flashing is plenty wide enough. 1 1/2" would be the minimum I would use.

Bury it just below the surface. 1/2" to 1" is fine. It's the bonding to the rods that's important.

Not knowing how big your ground rods are and unless you wanna spend large sums of money on some more copper for the correct clamps. This is where you have to be inventive. Bonding is critical. All bonding means is secure connections to assure physical and electrical connection is maintained. I used the largest split bolt I could find, coated the ground rod with Penetrox, wrapped the copper around the rod in a spiral and installed the split bolt over it as tight as I could. And it's pretty tight!

Now here's the best part. What you're planning on doing is adequate. And likely better than most hams.

HTH - Jim

[KB4MB]

Absolutely it helps! I have read countless threads, articles, websites, and everyone has some STRONG opinions (violent, even)! Knowing I am not messing up things is a huge help. This stuff isn't cheap, and I don't want to poke any more holes in the wall than necessary! Also, I know an incorrect ground is worse than no ground when it comes to lightning.

The copper braid is just to the copper pipe. 1" stuff, and I will pick up at the hamfest. For the outside connection from the pipe to the safety rod, I will pick up the fattest wire Lowe's sells. Only need a few feet of it anyway. From the safety rod/ground of the house wiring to the flashing, I will be using a split bolt to transition wire to flashing, with several washers

Now, from this point on, I will try the spiral and hose clamp, or split bolt idea.... I guess I didn't think that would be good enough, but then again, I guess I can't see why it wouldn't be good enough Just go from ground up around the pole once or twice and back down, and then a couple of clamps to hold in place, right? Or was my original idea of another split bolt and washers drilled through the flashing, with a large wire from this bolt to the rod ok? This way I don't have to go up above the surface and back down again... I'm good either way as long as they both are good enough...

As for my station upgrades, the interconnects I think are going to solve everything that isn't perfect in my setup - currently I connect from the rig to the MFJ noise canceller (never use it except to tune out the tv interference I get from the other room on a few frequencies or a few birdies from a laptop) to the SWR meter to the tuner. These interconnects are RADIO SHACK rg-58 connects! The good ones I had from 20 years purchased at a hamfest had intermittents so I just used what I had. I will be purchasing coax and soldering up better ones this weekend.

Thanks again!
Kris, KB4MB

[KB1NXE]

Good to know.

Here's what I did to connect the copper strap (I used 2" heavy .032" thick stuff).

I brought the copper strap to the ground rod at a perpendicular to it and then wrapped it tight against the rod in a spiral (go up or down with the spiral, doesn't matter) until you have at least 3/4" clear so you can get a split bolt over it (Channel locks work to make this wrap). Put on the split bolt and tighten with the best wrench you have. Tightness is the key. Don't forget the Penetrox. You can wrap the connection if you like, just not necessary.

Another method would be not to drive the rod in the last 6", make your connections and then finish driving it in.

The thing to understand Kris, do the best you can with the resources you have or can afford. You're on the right track.

And just so you understand more, a bad ground usually results from poor connections or connections that oxidize and corrode. Take extra care to prevent this from happening and you should be OK.

[KB4MB]

I went to Lowe's and picked up the supplies - that flashing is so soft and pliable, I think I will just use that instead of braid from the equipment to the bar. Save me money and it will work better! It does have sticky tape on one side, so I guess i will have to clean that off with some gasoline after I cut it.

Also, I found some bronze clamp that looks like it will do the trick. It has an insert for the wire, and then a flat strip that is about an inch long on top with two tightening screws... I just have to punch a hole for the two screws and I will be set.

Thanks again for the help!

[K3STX]

Knowing I am not messing up things is a huge help.

When I was a novice in 1978 I was a 15 year old kid with a Heathkit DX-100 TX and a 1930s Hallicrafters S-20R RX. My "shack" was my bedroom on the second floor. My antennas were 80 M inverted V and a 40 M dipole (also used on 15 M). My "ground" was a wire, probably 16 gauge, that ran out my window to a ground rod, probably 30' run of wire. No baluns on antenna, just coax all the way to my antenna switch. All grounds were "daisy-chained".

Antenna's were cut to "resonance" using 468/frequency. That was it!! There was no trimming. I did not have an SWR meter, if it worked, it worked! I have no idea what the SWR was. When I got my general and wanted to work 20 meters I tried my two antennas and whichever one could load better was the one to use!

Everything I just said is true, yet almost everything is also completely WRONG for "good operation". There was no internet to access so people can tell you how dumb your set-up is, no 15 year old Ham radio clubs, no real elmers to help you OFF the air. It was all done ON the air, and since things were working I never thought to ask how it could be improved.

It is a miracle we made contacts back then, but we did. There is something to be said for KNOWING what the "right way" is, but then there is also something to be said for being able to enjoy yourself and not dwell on little things. I am sure laying down 50 more radials on my 80 M vertical will help too, but am I really going to do that for 2 dB gain? At some point good enough is good enough.

paul

[W8JI]

I have a ground bar at the desk, and I will be using copper braid for the connects to the bar using hose clamps (I want it to be flexible and not cut me or my cables up - largest run is 1'). First problem: From the bar to the service ground (outside, three feet away), can I run a heavy wire, or will I screw up my rf ground by doing that?

What you do at the desk does not mean much, unless you have older two-wire plug gear.

http://www.w8ji.com/rfi_rf_grounding.htm

We ALWAYS have to bond the station entrance ground to the mains ground. That is the ground you need. Always.

From the service ground out two the two additional ground rods I have, I can run the flashing (3" wide enough?), but then, how to attach to the ground rods? Can I use jumper wires and split bolts?

It is a waste of flashing to use flashing between ground rods. A ground rod typically has dozens of ohms RF resistance. Why would you want a low RF impedance connection between something that has very high RF resistance?? Just use a heavy solid wire, like number 8 or larger. If you added radials flashing could help.

Flashing goes where you need minimal impedance, like between low impedance lightning and RF grounds or connecting to a low resistance radial system.

How far down does the flashing need to be buried.... is 1/2" ok? The ground is super tough here lately, and I have a horse farm and loads of manure/compost, so I was thinking of just rebedding that area anyway and adding soil instead of digging...

My flashing at the house is on the surface, but it could be buried.

Right now, I run a skywire loop fed with twinlead, but I am curious to see if an RF ground will help improve anything (I assume not at all, but still curious).

If the ground improves things, you have an antenna system or feed system problem.

Maybe one day I will put up an inverted L, so I figure try to run a ground now. The second rod is where the antenna feed line comes down (right in the middle of the layout), and I will get one of those sparkplug arrestors, just for shiggles. We do get lightning around here, and it has hit my pastures before. The third ground rod is where I figure I would put an L one day, and have left the rod above the surface a bit to attach radials if I want/need to.

Ground rods by themselves make terrible RF grounds for end-fed antennas, or for any RF ground.

The important point is the cable and power entrance. I have big towers (four of them 200 feet and taller) and lightning hits here all the time. I never have equipment damage doing things the way I do them.

73 Tom

[KB4MB]

It is a waste of flashing to use flashing between ground rods. A ground rod typically has dozens of ohms RF resistance. Why would you want a low RF impedance connection between something that has very high RF resistance?? Just use a heavy solid wire, like number 8 or larger. If you added radials flashing could help.

Well, from this forum of course! http://forums.qrz.com/showthread.php?t=35979 (and countless other posts!)

Specifically AG3Y

At the transmitter building itself, copper flashing ( not aluminum ! ) is used to fasten directly ( with CadWeld ) to buried copper rods at least 10 feet long, if I remember correctly ! The copper flashing can go completely around the building, forming a closed loop, and the rods are fastened at several places, I believe about 10 feet apart.

And K9STH

What I have found that works is to use a plated "crimp" or "solder" lug on the end of the wire that goes between the flashing and the ground rod. However, I always solder the lug to the wire no matter what. Also, whenever possible, I try to keep the aluminum inside the building and go through the wall with the wire. Flat strap does work better than wire. However, when you have to go through a wall, it is much easier to do so with wire. I also recommend using the heaviest gauge wire as possible between the flashing and the first ground rod. It is also possible to use copper pipe or copper tubing for this "wire". Since r.f. travels on the outer surface of the conductor it doesn't really matter if it is solid or hollow.

$30 for the roll isn't a big deal, so I don't mind cuting it up and burying it. I will be using #4 for the copper pipe station bus to the safety ground through the wall... It works out to 40 ft of 3" and 20ft of 2"... If I cut it all at 2" it would be longer, but I don't need length for the location I am in...

--Kris, KB4MB

[W8JI]

$30 for the roll isn't a big deal, so I don't mind cuting it up and burying it. I will be using #4 for the copper pipe station bus to the safety ground through the wall... It works out to 40 ft of 3" and 20ft of 2"... If I cut it all at 2" it would be longer, but I don't need length for the location I am in...

--Kris, KB4MB

Nothing wrong with flashing, but if you are only driving some rods in the ground, heavy wire might be more convenient. If the rod has several ohms to several dozen ohms resistance to earth, the change in sysyem impedance going from a heavy wire to 4 inch flashing is negligable.

Nearly all of the equipement protection comes from what you do for an entrance panel, and how that entrance panel is tied in to the mains ground or the mains feeding the radio room.

If you don't have an entrance point that is bonded to the mains, you aren't doing much for protection no matter what else you do.