1
$\begingroup$

I have a very simple home HF setup, just one wire antenna. I'm having a ground rod installed soon, and am planning the best way to set up my exterior buss bar.

I'd really like to do an all-in-one solution right on the ground rod, like this:

example

In this configuration, a lightning arrester is mounted directly to a copper plate on the rod, and I'd run my ground strap right off the same plate into my shack.

This is very appealing and simple, and avoids more complex mounting solutions to the exterior of my house.

However, the lightning arresters and coax will be exposed to the elements. How are these typically weatherized? I don't see any examples of this in any photos, though it's regularly shown that this is a viable setup right on the ground rod.

I already have some weather proofing tape for coax, would it be enough to cover the connectors going in and out of the lightning arrester? Do I need to do more? What's best practice?

I can't find any examples that weatherize this kind of on-rod setup. Thanks.

$\endgroup$
3
  • $\begingroup$ Will you protect the mains feed to your equipment at the same point, or near by? How far is it from this point to the radios? Impedance from shack ground to real earth isn't nearly as important (earth is many Ohms anyway) as equal potential across your equipment which means all incoming wires go through the same plate. Of course you try to divert as much current as possible as early as possible with earth rods on the tower, on the coax, etc. The polyphasers should be between unprotected and protected zones, so the protected-side coaxes never see any current. $\endgroup$
    – tomnexus
    Aug 27 at 0:16
  • $\begingroup$ Thanks. Re: "The polyphasers should be between unprotected and protected zones, so the protected-side coaxes never see any current" are you saying the setup in the photo I attached is fundamentally unsafe? $\endgroup$ Aug 27 at 1:39
  • $\begingroup$ Not so much unsafe - it's safe (until you get a strike) and probably better than nothing - but depending on what's connected to it, far from ideal. If you run coax a few metres into the house, then plug the radio into the wall mains socket, then it will not help much at all for direct strikes. See excellent answers to this question and also arrl.org/lightning-protection for some starting points. $\endgroup$
    – tomnexus
    Aug 27 at 4:25
3
$\begingroup$

Don't forget that for the sake of lightning protection, you should bond your ground rod to the ground rod at your electrical service panel, underneath where the electrical mains enter your house. This is required by electrical code in the US. Ideally all your feed lines should enter the house through a single service panel also, which is near the electrical mains service panel and bonded to it. I would strongly recommend that you give up some of the simplicity of your proposed solution and wire your antenna to the house according to the electrical codes that apply in your jurisdiction. Otherwise your station and your house would be very vulnerable to nearby lightning strikes, even if you disconnect the coax from the radio as the storm approaches.

Anyway, to answer your question, I would wrap the coaxial connections and about 4" or 10 cm of the coax with black self-fusing stretchy silicone tape, which is great for keeping water out. (Why black? That color resists fading and embrittlement from UV light the best.) Then I would put an upside-down bucket or something similar over the whole thing to protect the connections from rain and snow.

If a bucket isn't fancy enough, then you could sink a pressure-treated wooden post next to your ground rod into the earth, or in concrete, and then mount a box meant for electrical connections on the post, and have the coax and the ground rod come up through holes in the bottom of the box. Don't try and seal the box completely, because condensation would inevitably get inside and cause trouble. Leave some "weep holes" in the bottom of the box to allow any collected moisture to drip out.

$\endgroup$
4
  • $\begingroup$ Thank you for the answer. Regarding "according to the electrical codes that apply in your jurisdiction", what is the best way to accomplish this? Will an electrician be well versed enough in antenna electrical codes to ensure my setup is compliant? If not, who is? I'm finding this information very hard to track down. I want my setup 100% to code. $\endgroup$ Aug 27 at 1:36
  • $\begingroup$ @User5754448 Electrical codes are to protect your life, not your equipment. Don't expect an ordinary electrician to know how to install lightning protection that will protect your equipment. $\endgroup$ Aug 27 at 14:06
  • $\begingroup$ Thanks Phil, I'm not talking about my equipment. I'm talking about meeting any code requirements, and especially ensuring safety and no problems with my insurance company. What's the best way to ensure that? Who is the expert to consult? $\endgroup$ Aug 27 at 15:59
  • $\begingroup$ Regarding how you can ensure that your antenna was installed according to code is a difficult question. In the US the NFPA's version of the electrical safety codes are available online for free. You need someone who can understand electrical safety codes and the reasons behind them. I'd say to ask around at a meeting of your local ham club and see if there are any hams who are electricians or engineers. If you have plenty of money you could hire a Professional Engineer. $\endgroup$
    – rclocher3
    Aug 29 at 1:03
2
$\begingroup$

That can be waterproofed with mastic tape or pads. Polyphaser sells an overpriced kit which is just a mastic pad (probably 3M 2229) and a roll of ordinary vinyl electrical tape.

The mastic comes in big pads or in rolls of various widths. A wide roll or pad will be easier to apply in this application, but you can probably find a 1" roll at your local hardware store which will also work. This stuff is very tacky and more like putty than tape. The mastic will be broken down by UV exposure so you can wrap over it with vinyl electrical tape or put it in some kind of box.

Protip: put one wrap of vinyl electrical tape around your connectors before you apply the mastic. If you do not, the mastic will ooze under the barrel you turn to unscrew the connectors and you'll never get them off.

Tangentially related to your question, if your objective is effective protection against equipment damage from lightning it's important that you have a single-point ground. I don't see any grounding for your AC power in this setup, so you'll want to consider adding that or introducing another grounding point where the feedlines and AC power meet up. See How can I protect equipment against a lightning strike?

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.