Grounding Do's Don'ts & Why Part 3

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AI5DH, Mar 19, 2012.

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  1. AI5DH

    AI5DH Ham Member QRZ Page

    High rise buildings have the best AC ground and lightning protection money can buy and inherent to every high rise building at no additional cost. Just the building Structural Steel. It is buried deep into the earth encased in concrete with massive weight keeping it into contact with dirt. The surface area of all that steel and concrete is massive. that no copper or silver conductor can match.
     
  2. K0BG

    K0BG Ham Member QRZ Page

    I haven't followed this thread very closely, but when you speak of high rise buildings, you peaked my interest.

    I wonder how many readers know about horizontal lightning? It is not so rare in the mountainous west between mountains. In fact, there is a commercial radio site west of Salt Lake City, that gets a lot of it. The reason I bring this up is, when it occurs between high rise buildings, lightning protection doesn't do much good. There is even a few recorded cases where people have been killed by it.

    Horizontal lightning also causes another phenomena few folks have ever seen—ball lightning. I've seen it once in my life, and at the aforementioned radio site. It is scary stuff to say the least!
     
  3. K9STH

    K9STH Ham Member QRZ Page

    If you want to examine the "direction" of lightning even more, there are numerous situations where a lightning strike goes upward, not downward. This is most common where installations on top of a mountain are above the clouds.

    Glen, K9STH
     
  4. K0BG

    K0BG Ham Member QRZ Page

    Actually, we now know that isn't really the case. Tim Samaras, WJØG, rebuilt a high speed camera using CCDs. It is capable of about 1.4 million frames per second. More on the story is here:

    http://ngm.nationalgeographic.com/2012/08/chasing-lightning/johnson-text

    Since I know Tim personally, I've seen a couple of the high speed movies. To say they're spectacular, is an understatement. There is to be a NatGeo channel feature coming soon, replete with movies of the captured strikes.
     
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

    The last few posts in this thread piqued as well as "peaked" (sic) my interest. Just yesterday, ABC News aired a segment (courtesy Nat'l Geographic) featuring Mr. Samaras and his BIG camera about lightning: http://abcnews.go.com/WNT/video/storm-chaser-captures-lightning-strikes-camera-16982263

    For maximum effect, I suggest viewing it on a big screen monitor, in a darkened room. :cool:
     
  6. WU3U

    WU3U Guest

    Hello all,

    I live in a small row home in Philadelphia.

    From what I read in this thread, there is no practical way to properly ground antennas in a row home.

    The house is surrounded by concrete. There is no grass, no backyard - just an alley behind the house that is maybe five feet wide, basically a place to hang out clothes and put trash cans.

    There is a cold water pipe close to the back alley - it has a spigot for a hose installed on it.

    To install ground rods would require breaking up concrete or drilling a hole through the cement...that can be done I guess, but in terms of a lightning ground, it would be useless since there is no way to lay down the radials that would attach to it. The best that could be done with ground rods is a DC ground...my entrance panel would not have a low impedance path to ground for lightning and from a practical standpoint, I do not see any way that and effective lightning ground could be installed here.

    The breaker box is located some 25 feet away from the only practical place where an entrance panel could be mounted.

    The house, built in 1916, uses the cold water pipes for all ground connections - even the breaker box is grounded to the cold water pipe system - there are no ground rods anywhere.

    This is common in Philadelphia row homes. I have lived in three, and all three had breaker boxes that were grounded to the nearest cold water pipe.

    I was planning to mount four masts in each corner of the 40 by 15 foot roof to support a wire antenna of some sort.

    Given modern standards for grounding a Ham station, I guess it has come to the point that row homes like this one are becoming off limits to Ham Radio....is this impression accurate?

    Remember, there is no physically practical way to run radials all around...heck, driving ground rods is hard here, and again, of not much use in terms of a lightning ground.

    73,

    Tim
    WU3U
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Tim, I assume you've already read stuff like this but just in case:



    Assuming your home doesn't explode and kill you in the process :p, which would be awfully rare, "good insurance" covers a lot of problems...
     
  8. NW9M

    NW9M Ham Member QRZ Page

    I'll chime in here on a couple of the topics I see raised-

    First, I do not see row houses or any other type of house becoming off limits to an amateur radio operator. Certainly there are antenna systems that are off limits due to legal, physical, or (especially!) economic limitations but there are always alternates available.

    Your mentioning ground rods in a concrete environment I found interesting as I have always been able to find some place to install one, but then I did a web search for "slugging" a ground rod and it has turned up empty so I though it would be beneficial to mention the technique here in case someone is not aware of this really simple method for installing them easily-

    In bare ground, just dig a hole about the size of a small coffee can and fill it with water. Now just take your ground rod and poke it into the center of the puddle as far as it will go, then pull it out. Of course now the water will fill up the hole, so shove it back in and it will go a bit further this time. Simply repeat this process and an average man can literally drive the ground rod to within inches of the ground surface this way, all you need is water and if you do not have a hose just a couple of buckets will work. I also like to pour some copper sulfate crystals in the hole but I do not know if it makes that much difference, if anything at all but try telling that to yourself when you are trying to work a weak station. Copper sulfate is still sold in hardware stores as a "root destroyer", so just ask where that is and look at the label to make sure that is what you are buying.

    I mention this as I've done this twice when I was living in the city and just drove the rods into a gap between 2 slabs, it is fast to do and when you are doing it it does not look like you are doing any major construction. One was a full size rod installed outside and the other was a shorter antenna/radio ground rod that I put in the corner of the basement where the foundation had cracked. You do not need to dig the hole in this case but a source of running water (it only needs to be a trickle) is convenient.

    And lastly, WB2WIK (Steve), thanks for the QSO last night on 17 where you were able to relay my questions on remote mounting my Icom 706 to WB2REM! You really had a booming signal and one of the best audio signals that I have heard in a while, I forgot to mention that before I signed off.

    73's de NW9M
     
    KC5YSQ likes this.
  9. TA4OK

    TA4OK Ham Member QRZ Page

    Thanks my friend 73''
     
  10. KF2I

    KF2I Ham Member QRZ Page

    So if my AC Service Ground is almost 75ft away on the complete other side of the house, is it still feasible to run copper to it and bond it to the rod I have for the coax coming into the shack? Would this run along the outside of the house? It's only 20ft or so inside to the breaker panel... but pretty far for the service entrance ground rods.
     

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