W1VTP station update - ground system installed in shack

[w1vtp]

All

Finished the inside work on the ground system.  I'll upload the pictures in two parts: original detail & final inside install.  Note in the original detail that the strap was pulled in after the slab was finished.  The strap is 16 lb X 8"

I have another copper strap, same size, that I plan on attaching to this one (braze? solder?) in a "T" configuration and this configuration will be the connection for several ground rods

Al

[w1vtp]

Here's the finished detail

Al

[KA3ZLR]

You Lucky Guy..


73
Jack
KA3ZLR

[w1vtp]

You Lucky Guy..


73
Jack
KA3ZLR

Jack.  I have one of those CE 29A units with the original VFO that I plan on resurrecting.  I may be knocking on your metaphorical door for some tips

Al

[KA3ZLR]

I Hope I can Help...


73
Jack
KA3ZLR

[KB2WIG]

Thems Cu 'bells' set the buss off nicely......  did you 'ufer' the footings?

klc

[WA1GFZ]

Al Home Depot sells solder with silver content but you will need some flux.
Make sure you tie in the service and tower grounds. My building inspector like the #4 solid I used.

[Opcom]

That's a ground we can be envious of!

[KM1H]

You may be grounded but where do the Beverages go?

[W2PFY]

I think you better braze them. Maybe Don, K4KYV will jump in here, he has some idea on that as other may well have.

2C's worth.

[KA2DZT]

Al,

Nice ground system.  Ground the base of the tower to your ground strap.  I would put at least one ground rod about a foot from the tower.  You can add more ground rods along the strap.  You need to connect your station ground system to your AC panel ground.  You can use #6 or larger.  Make the connection near where the station ground enters the building and run the #6 to the AC ground as direct as possible.  The #6 can be run inside or outside.

Fred

[K5UJ]

If you have enough heat and are soldering new copper to copper you don't need flux with silver solder.  If you have any right angle turns with the strap don't fold it over; cut it and solder it.  With big wide strap like that you are probably better off with brazing (however it is spelled).

How high is the tower going to be?  if it is going to have a big beam or something that catches the wind it may twist on that base in concrete.  Sorry to be critical Al, most everything looks real nice and professional.

[w1vtp]

Here's a look at the proposed ground system looking down.  Another strap will form a "L" from which galvanized chicken wire fence will be attached to form a "h".  Ground rods will be driven at intervals along the straps.  The fence material will be held to earth using temporary staple shaped wires. Eventually the grass will entrap the fence holding it to the ground.

This will form a sort-of counterpoise under the antenna.  The antenna will soon be at 70 feet in the center.

This tower/mast is for my wire antenna and local VHF / UHF antennas.  I plan on another tower north of the shack for HF yagis etc.

Anyway, that's the plan pending suggestions for improvement.

Al

[KB2WIG]

I'd reconsider the galvanized/ copper connection. If in direct contact, the copper and zinc will corrode after a while.

How are you going to conect the two metals?

I supose you can wash the galvanization off of the metal (HCl) and then solder sweat them together.
Or sandwich some stainless steel in between the two and use a ss bolt to bolt them together. I'd try this method and keep the  'joint' as water proof as possible.


klc

[K5UJ]

Okay Al FB.  I did not know what you planned to use the tower for but if it is wire and a TV antenna it should be fine, especially since it is not going to be real high.

The one for HF yagis might benefit from being on a base plate held with a pin so it can rotate and let the guys absorb the forces on it.

The thing with the fence junction with the copper is iffy.  I assume this is a pretty permanent installation.  It may be okay but personally I avoid unions with copper and non-stainless steel and aluminum.  The three don't seem to like each other.  I have copper carrying RF from the feedline to my aluminum 75 m. vertical and I use a brass washer between them.  Brass doesn't react--it is okay between copper, and galv. steel or aluminum.  As much as possible I just stick with the same metal to avoid this type of problem, but in your case, copper mesh while available from Georgia Copper (www.georgiacopper.com) is probably pretty expensive.  well I just checked and yikes $16 / foot for 3 feet wide runs.  So if it were me, and I wanted to go the two runs of fencing route, I'd simulate the fencing with lots of runs back and forth of no. 14 solid copper wire.  I am not sure what you are trying to achieve with the ground system -- maybe you don't even need it?

[KA2DZT]

Al,

The fence idea is a bit iffy.  The galvanized chicken fence will just rust in a short time.  We used the chicken fence above ground for the garden and it's shot and all rusted in two seasons.

I don't think you really need any type of counterpoise.  If you want to use a counterpoise I would invest in some bare copper wire or even covered copper wire.  Run out some radials wherever you can.

The counterpoise is for what freq??

A counterpoise buried for VHF is useless.  For HF like 75M, you need some long radials to be effective.

Keep in mind, the main purpose for the station ground system is for lightning.  To repeat my previous post,  you MUST connect your station ground system, whatever it is, to your AC panel ground as I previously described.

This may not seem or even look too important until you get a strike from lightning.  Once you drive another ground rod into the earth, your QTH now has two grounds that are at two different locations in the earth.  One at the station and one back at the AC service entrance.

Because your equipment is powered from the AC service, everything is essentially grounded through the AC plugs back to the AC panel ground.

A lightning strike anywhere on your property can create enormous voltage gradiants between the two ground systems.  This voltage difference is usually equalized through your equipment which is now connected to the two different grounds.

To lessen the chance for damage, connect your station ground system to your AC panel ground with as large a copper wire as you can, #6 or larger.  You can also use large gauge aluminum.  Multiple runs of #6 is even better.  It would seem that we're trying to reduce the DC resistance between the two grounds.  This is true, but what is even more important is to reduce the inductance as much as possible.

Lightning has an extremely fast rise time.  Ground wires that have a lot of twists and turns have too much inductance and can become less effective.

Fred

PS.  If you're going to run your entire station from stand alone batteries, disregard all previous instructions.

[w1vtp]

Fred & all:

I disconnect without fail all my rigs and antennas.  I have my YL KA1HTS trained to check the connections if something gets nasty.

I wouldn't trust any ground system for nearby strikes.  But I'm going to try my best.  The other part of this grounding system is that I plan on having an ESD station for the non hollow state projects.

Comments about the metal difference between galvanized fence and copper strap is taken.  I'll have to think about it
.
Al

[Todd, KA1KAQ]

Looks very nice, Al. The copper pipe provides a good buss with plenty-o-room to lash things onto it. I used the same approach for my first ground buss years ago, except I used electric fence insulators in leu of the copper type you used. Fastened them to a board with brass screws and used stainless steel Gates hose clamps for the ground wires while looking for a better alternative. Used the cable from one side of an old set of car jumpers to the rod outside, worked slick.

I agree with Fred and others on the radials. Keep your eyes peeled at NEAR-Fest or elsewhere for a big roll of cheap copper wire. Doesn't need to be heavy gauge. Then just start laying them as time permits. Don posted some info on his installation of ground radials a while back.

And yes - the safest approach to preventing damage is to disconnect not only the aerials, but also the AC connectors. With multiple things plugged into an outlet strip, it's easy just to yank one plug or however many strips you use, provided the outlets are at bench level and don't require crawling around on the floor and behind things. Thunderstorms are a much bigger issue here in the south, we've taken damage from hits the last 2 summers. I've got 2 power strips that are a cinch to unplug, one plug for the big rig, and 2 feedlines. Takes about 30 seconds to disconnect everything. Fingers crossed, no damage to any radio gear so far.

[KB2WIG]

The only problems that I see with the disconect methode are....

Yer not around when Thor visits.

How do you disconect the grounds from the rigs? The radio(s) are still conected to one part of your power/antenna system. Granted, having the power 'lines' physically seperated will decrease the chance of the equiptments being damaged. And the lightning surge doesn't jump out of the ground to attack.      I would appreciate some comments on this.


I do like the Cu pipe method. My paved driveway and garage overhead door entrance get in the way of my ground system.  Soo, I've got a piece of 1/2 Cu pipe layed up against the threshold of the garage door. One end havs some #4 to connected back to the service ground, the other to the antenna lead in ground rod. So now I can tell people that I've got a dirty green system.


klc

[flintstone mop]

hey AL,
I'll have to take a pic of my radial system standing near the top of an 8 foot ladder to give a good view. of 6 or 7?? vinyl covered, welded fence, 3 feet wide and 50 feet long for a hopeful helluva radial system.
The grounding "halo" around the shack would make Motorola jealous. We spent big bux for those halo ground systems and a mess of aluminum buried under ground and tied to the tower at all of our trunked radio microwave sites. They try to get less than 1 ohm resistance to ground. We took direct hits and only minor damage. The idea is to connect each piece of equipment separately to the ground inside. If there is a nearby hit or direct (shudder) everything will rise and fall, at the same potential, during the surge, at the same time.
Fred

[WU2D]

Step1. Verify the technician is grounded.

[w1vtp]

<snip>

How do you disconect the grounds from the rigs? The radio(s) are still conected to one part of your power/antenna system. Granted, having the power 'lines' physically seperated will decrease the chance of the equiptments being damaged. And the lightning surge doesn't jump out of the ground to attack.      I would appreciate some comments on this.


<More snippig>

klc

Excellent point. I'm going to have to think about that. My approach up to now is to completely isolate my equipment from the universe, electrically.  However, having a fair amount of repeater experience, I am aware that we have survived some pretty close hits - and one direct hit with no real damage to the repeater equipment.  However, the control line was another story **POOFF!!**

I think a visit to my local electricronic junque store ESS and looking into some real beefy DC connectors might be in order.

Al

http://www.esssurplus.com/

[W1AEX]

You need to connect your station ground system to your AC panel ground.  You can use #6 or larger.  Make the connection near where the station ground enters the building and run the #6 to the AC ground as direct as possible.  The #6 can be run inside or outside.

Fred

Fred,

One of the things on my list of tasks this summer is to re-do the bond between the station antenna grounds and the electrical ground. I never thought to run that from the entry point of the antenna feedlines (where the station ground is) through the basement over to the AC panel. That would be about 20 feet shorter than running around the side of the house to the point where the electrical system ground is. It would be a lot neater too. Sounds like a good idea.

Rob W1AEX

[K5UJ]

wellllll, I was going to keep the bond between shack and service grounds outside, using 2 or 3 inch wide copper strap.

1.  The idea seems to be to keep lightning strike current flow (gradient equalizing) outside as much as possible.

2.  If the bond between the two is outside, it can be buried, i.e the whole thing is grounded as in ground potential.

Count me as one of the perhaps, excessively cautious--I spend a good 15 or 20 minutes disconnecting all feedlines and moving them away from the house, er live-in ham shack, and unplugging everything feedlines and service outlets inside, but leaving the straps to the single point shack ground connected.  Of course the problem with this is, being lazy, I don't operate as much in summer because I don't take the time to connect and fire everything up if I think I'm going to have to undo everything again two hours later.

[KA2DZT]

You need to connect your station ground system to your AC panel ground.  You can use #6 or larger.  Make the connection near where the station ground enters the building and run the #6 to the AC ground as direct as possible.  The #6 can be run inside or outside.

Fred

Fred,

One of the things on my list of tasks this summer is to re-do the bond between the station antenna grounds and the electrical ground. I never thought to run that from the entry point of the antenna feedlines (where the station ground is) through the basement over to the AC panel. That would be about 20 feet shorter than running around the side of the house to the point where the electrical system ground is. It would be a lot neater too. Sounds like a good idea.

Rob W1AEX

Rob,

All your antenna ground rods should be bonded together outside (if there is more than one antenna ground rod in the ground)  From that system of rods a single ground wire can enter the shack for equipment grounding including antenna lead-in cables.  Somewhere near that entry point you should run the bonding wire to the AC service ground electrode (outside or inside, whichever is more direct).  The electrode is defined IIRC as the AC ground rod, the ground wire between the AC panel and the AC ground rod, the AC panel itself, metal conduit on the service entrance cable, the cold water feed pipe where it enters the building if there is an AC ground wire to the water pipe or the ground wire itself between the AC panel and the cold water feed pipe. Whichever is most direct.

The theory is that all your antenna ground rods bonded together outside (as one) is considered one ground electrode or contact point with the earth.  The AC service ground electrode is another contact point with the earth.

Another thought,  If your bonding ground wire runs near or past a water pipe in the basement, bond your bonding wire to the water pipe at that point.  You could then also continue the bonding wire to the AC service ground electrode as defined.

Fred