Need advice on new antenna install...

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KG0BA, Jun 2, 2021.

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  1. KG0BA

    KG0BA XML Subscriber QRZ Page

    I have a new installation of an Isotron 20 antenna. The Isotron 20 is a 20 meter antenna, clamped to the top of a 36' aluminum mast. The mast is supported with stand-off brackets to clear the guttering on the way up, and the bottom of the mast fits over a black steel pipe that is concreted in the ground in order to isolate the mast from lateral movement.

    The coax runs down from the antenna feed point about 20 feet, where a lightning arrester is placed within the feed line. The coax from the lightning arrester runs into the attic, and down a PVC chase that runs from the attic to the basement where the shack is located.

    With respect to any of these scenarios, it would be about 60 feet to the outside utility ground rod, whether going through the attic, or around the house with the ground wire buried in the soil. None of the scenarios would be a straight shot to the utility ground rod on the opposite side of the house for bonding purposes. All of the scenarios would probably present a few 90 degree bends to the ground wire before I would be able to tie into the utility ground rod on the other side of the house for bonding purposes.

    How would you ground the base of the mast?

    Scenario #1:
    The ground wire from the lightning arrester could be clamped to an 8ā€™ ground rod at the base of the antenna mast, then a wire buried in soil from the ground rod at the base of the mast to the utility ground on the other side of the house.

    Scenario #2:
    Omit the ground rod at the base of the mast, but connect a wire directly to the base of the mast using a clamp, then bury a ground wire in soil that runs around the house to the utility ground rod on the other side of the house.

    Scenario #3:
    Ground the base of the mast directly to an 8ā€™ ground rod at the base of the mast, and forget about trying to also bond to the utility service ground.

    Scenario #4:
    Omit the ground rod at the base of the mast, and route the ground wire into the attic from the lightning arrester, down through the PVC chase that the coax uses, then connect the ground wire directly to the utility ground wire that runs from the circuit breaker box in the basement directly to the utility ground rod outside using that same utility service wire from the circuit breaker box, resulting in a bonded connection of the mast to the utility ground rod on the outside of the house.

    Bringing the wire into the attic, and down the PVC chase would be easiest, since I could avoid having to bury a wire in the soil. Some might say, and they may be right, that bringing the ground wire from the mast into the house through the attic would be an unwise thing to do. But, it seems to me that as long as the ground wire I use is of a sufficient diameter, probably #2 or #3 wire, preferably insulated, then it should be no different than lightning striking the utility service where a lightning charge would enter the house through the inside circuit breaker boxes, versus bleeding off a lightning strike from the antenna mast. With a decent quality lightning arrester, chances are the charge from lightning wouldnā€™t enter the house anyway, hopefully.

    Other ideas are welcome as well...What say you?
     
    Last edited: Jun 2, 2021
  2. AK5B

    AK5B Ham Member QRZ Page

    Yikes.

    I suggest you start reading well-established station grounding references and don't even think of bringing anything into your attic or house without being bonded to the AC service panel ground electrode FIRST. That includes any and all ADUs, coaxes, control cables and wires clamped to metallic masts.

    Forget convenience; it's all about safety and shunting static and lightning surges to ground before it gets to you and your gear.

    Once that is done , route said cabling over to the ham shack (but the best way is in very close to that single point ground by the service panel, not some other place far away from there---in a nutshell).

    Check out some of the grounding threads over in the General Technical Questions forum, too---lots of good info available there).

    Stay safe! (and good luck with that Isotron---I will refrain from commenting on that issue for now.) :D

    73,

    Jeff
     
  3. KG0BA

    KG0BA XML Subscriber QRZ Page

    I've already read it ALL, and I've always practiced bonding to the utility service electrode. Every piece of equipment in my shack is properly bonded to the utility service electrode.

    None of the scenarios mentioned bringing a grounding wire, coax, or any other conductor into the house or attic without also bonding to the utility service electrode.

    These scenarios represent the array of various kinds of advice I've received from experienced HAMS, as well as tech support gurus at the supplier level that have been at it for years.

    Thanks for your concern relative to safety issues, but which of the scenarios would you choose, if any?

     
    Last edited: Jun 2, 2021
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Scenario #1.

    But if it was me, I'd move the antenna mast location and bring all cables into the house close to the service panel.:)
     
    N5XH and AK5B like this.
  5. KG0BA

    KG0BA XML Subscriber QRZ Page

    Yep, I wish I could, and I agree with you totally, but that's not an option. That's why with all the different variables that are unique to each application, those variables effect the grounding (bonding) techniques we have to choose from. Reading the publications that are out there on the subject of bonding don't address all the divergent application variables we sometimes face.

     
  6. AK5B

    AK5B Ham Member QRZ Page

    OK, all well and good there, but you lost me as soon as I read, "...forget about also trying to bond to the utility service ground" in option #3 and I skimmed through the rest rather quickly.

    I'm with WIK on Option #1 if there's no other way to change the scenario and good luck with it working out for you.

    73,

    Jeff (also an experienced ham as well as a HAM---Humorous Adult Male---at times, too)
     
  7. KQ0J

    KQ0J XML Subscriber QRZ Page

    Just load up the 36' mast as a vertical , it will outperform the Isotron.
     
    AK5B, N5XH and AD5HR like this.
  8. KG0BA

    KG0BA XML Subscriber QRZ Page

    Would you believe that that was a recommendation from the tech support at one of the largest suppliers of HAM gear. My only apprehension at that recommendation was that wouldn't it produce a ground loop, with everything else bonded to the utility service ground, not to mention relying solely on a ground rod that isn't bonded to the utility service ground electrode?

     
    Last edited: Jun 2, 2021
  9. KG0BA

    KG0BA XML Subscriber QRZ Page

    Well, to further elaborate, I already have a Hustler 6-BTV trap vertical installed within about 60' of the electrode, a straight shot to the grounding electrode rod at the outside service panel, and it's good for 10-80 meters. The Hustler trap vertical has about 40 radials under it, it's my primary antenna, and it works great!

    I got the Isotron 20 about 22 years ago as a Christmas Gift, and it has been sitting in my basement in the box for 22 years. The Isotron antenna functions more similarly to a dipole, and since I already have a functioning trap vertical, I figured I would install the Isotron 20 as an alternate antenna design for when band conditions dictate.

    I had it up about 20 feet off of ground level when I tested it, and I made a contact with a HAM over in Pennsylvania (I'm in Eastern Missouri), and when we compared the signal off the Isotron 20 to the signal he was receiving off of the Hustler 6-BTV vertical, the Isotron was S9 +20 compared to the S9 +10 off of the trap vertical. The only down side was that the Isotron noise floor was slightly worse on my end, but not too bad. I attribute that to it only being 20 feet off of ground level, and not yet properly grounded to the electrode, etc...I theorize that the noise will be reduced once it's properly grounded and it's up another 10 feet higher off of ground level.

    I was shocked at the Isotron's performance, and the other HAM went on and on about how he could hardly believe it. Anyway, when I get it up to about 32' off the ground, it should perform even better. I'll see how things go. If I find I'm ultimately disappointed in the Isotron, then I'll probably go with a conventional trap dipole configuration using the same mast.

     
    Last edited: Jun 2, 2021

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