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Lightning Arrestors in 30 seconds

How do you attach a light­ning arrestor to your Heli­um hotspot anten­na? What does one look like? Is it dangerous?

Let’s start with a pic­ture. This will answer 90% of your questions.

Now, let’s talk about what you can expect a light­ning arrestor to do. Hint: It won’t stop a bolt of lightning.

A light­ning arrestor con­nects the anten­na to the anten­na cable. It pass­es the RF sig­nal from one to the oth­er through a medi­um that, when it gets too much pow­er, it breaks, just like a fuse. RF engi­neers will prob­a­bly lose their minds when they hear it explained that way; they’ll start spout­ing about ion­ized gasses and fixed gas dis­charge tubes and input/output surge mag­ni­tudes. They’re right, but you don’t have to know all that to use a light­ning arrestor. 

A light­ning arrestor will NOT stop a direct light­ning strike. That would anni­hi­late your house. While it would be awe­some adver­tis­ing to see a pris­tine hotspot mirac­u­lous­ly pro­tect­ed in the mid­dle of a charred and black­ened house hit by light­ning, it would­n’t be true.

All a light­ning arrestor real­ly does is pro­tect your elec­tron­ics against the sta­t­ic elec­tric­i­ty that can build up dur­ing a storm. If the ener­gy feed­ing into your anten­na (don’t kill me light­ning sci­en­tists!) gets too high it zaps the gas in the mid­dle of the arrestor, break­ing the con­nec­tion to the anten­na cable, and all the ener­gy is divert­ed to that ground wire (which is hope­ful­ly attached to your house ground.)

So, uh, how does it work? Just screw the thing in between your anten­na and anten­na cable, con­nect the attached ground­ing wire to a met­al “path” that goes all the way to the ground and you’re done. 

Wait, you want more? What anten­na is that? Where did I get that mount? What’s the inser­tion loss on this light­ning arrestor (make sure you get the right con­nec­tors!) vs the stuff the mil­i­tary uses when they don’t want to fritz out a $40,000 piece of elec­tron­ics? Psst, just get the Par­ley Labs one.

I’ll start with the anten­na. I don’t know what it is. A friend brought it over. He said he’d bought it on eBay and what did I think of it? I thought it would make a good demo for this light­ning arrestor post, so I just gave him a Near­son 8 dBi I had lay­ing around and kept his unknown anten­na, which had the only thing that mat­tered: An N‑connector on the bottom.

What about the mount? Made that out of alu­minum bar, twist­ed, drilled, and ground to fit. Should’ve drilled first, but I made it work. The oth­er super cool part of this project is the use of rivnuts. Stop here if you want to learn any­thing more about light­ning arrestors, and refer to the above picture.

Just because I love build­ing stuff and shar­ing knowl­edge, here’s the jour­ney. I start­ed by clamp­ing the alu­minum bar in my vise, then twist­ing one end 90 degrees. 

Twist com­plete. Noth­ing fan­cy, just sim­ple and func­tion­al. I’ll leave that pink paint on the end of the bar. Pink means you like to party.

Then I drilled out the holes I’d need for the anten­na mounts and the pole mount. 

I love that drill press. A ran­dom guy gave it to me. I saw it in his garage and com­ment­ed on how old and rad and heavy duty it was. He said, “That thing’s dan­ger­ous, I watched my grand­fa­ther lose the end of his fin­ger in it. Do you want it?” Yep.

It weighs about as much as I do. I love heavy metal.

Next, I laid out what I’d need. Anten­na, light­ning arrestor, ground­ing wire, easy dis­con­nect ter­mi­nals, and a rivnut. Aw yeah, rivnuts!

Ok, what’s a rivnut? 

It’s a cool lit­tle way to add a nut into a thin walled piece of met­al. You drill out the hole, screw the nut onto a rivnut tool, insert the sleeve into the hole, then com­press the sleeve of the nut, secur­ing it to the wall of the pole.

Here’s what it looks like. That’s ready for a 10–24 bolt, which I hap­pen to have a bunch of.

I used a u‑bolt to clamp on my demon­stra­tion anten­na mount.

Then I had to make the ground­ing wire. I used 12 gauge cable for this demo, most specs require 10 or 12 ga. You need to crimp on quick con­nect ter­mi­nals to both sides, then seal the heat shrink around ’em. Here’s what it looks like with the wire stripped, before I made the connection.

Here’s what it looks like once you crimp it.

I crimped both sides, used a heat gun to shrink it down all tight and pret­ty, and I had my ground­ing wire. You want these to be as short as possible.

All that was left was to con­nect every­thing up. Here’s what it looks like with­out a bunch of words past­ed in. Yes, I could’ve made the ground­ing cable short­er. I just didn’t.

Pret­ty sim­ple, right?

Oh, and the inser­tion loss? Let’s be mean and call it .5 dB. If you’re deploy­ing for a crit­i­cal appli­ca­tion and want to drop $150 on a badass Nex­Tek Surge Guard light­ning arrestor with < .1 dB loss, you can do that because every tenth of a dB counts. But.…you don’t have to.

Ok, that wraps up light­ning pro­tec­tors. You don’t need to do any of the building/light fab work I did, you can just screw it into your anten­na and use the mount that comes with any decent anten­na. It’s sim­ple. You got this! 

41 thoughts on “Lightning Arrestors in 30 seconds”

  1. Hi Nik, would love to buy a cou­ple of your home made brack­ets that mount to the pole. 

    They look so dif­fer­ent and obvi­ous­ly cus­tom made. 

    Nice to have some­one in the HNT com­mu­ni­ty explain­ing the cor­rect way of doing things.

  2. Great stuff as always Nik. Can I put the arrestor at the end of the cable near the ground where I will be putting a ground­ing spike? Or does it have to attach to the anten­na. As my anten­na will be on my roof and no place to ground up there.

  3. Right on Lar­ry. You can total­ly make ’em your­self with a vise and a few clamps. If you’d rather just have me make ’em for you, reach out via the Con­tact Form for a quote. Thanks again!

  4. Can you ground it off any­thing that qual­i­fies that is near by or do you have to ensure it is ground­ed all the way to your house ground or a new­ly pound­ed in ground rod? I’ve been pre­pared to run the ground wire all the way down the side of my house, but if I can ground it on some­thing clos­er, that would be great.

  5. Hi Dan, there has to be a sol­id con­nec­tion all the way to the ground­ing rod/house ground. Can’t just attach it to the near­est met­al “thing”. 🙂

  6. Thanks for the great info Nik.
    I’m look­ing to put my anten­na at the top of a wood­en post (get’s me anoth­er 4mtr above rooftop, in a very flat area), so how/what/where do I attach the ground­ing wire com­ing out of the arrestor?
    FYI I will be run­ning pow­er cable up the post as well, giv­en the HS plug is only 2‑pole (not earth­ed) could I poten­tial­ly run a 3 wire cable and use the earth­ed wire to con­nect to the arrestor?
    Thanks in advance, S.

  7. Hey Nik. I have the light­ning arrester and some sol­id cop­per 8 awg cop­per (I know it’s prob­a­bly overkill) this fits in the light­ning arrester ter­mi­nal per­fect­ly! Is that ok that I use bare cop­per wire and no sheath­ing? I see you are using braid­ed cop­per wire I think.l with ter­mi­nal con­nec­tors. I want to run that from the arrester to the ter­mi­nal clamp I bought to fit my mast. Then from there I was going to run a sep­a­rate cop­per wire down to my cop­per rod and con­nect it to the ground­ing clamp there. I was going to go to house ground which is only a few feet away, I just want­ed to make it tidi­er lol. Does this seem right?

  8. You know, I’m not sure. I’d think the sheath­ing would be pret­ty impor­tant, but I’m not an electrician.

  9. Hi Bruce, typ­i­cal­ly you get what you pay for, though that can be off­set by pay­ing more for a name brand. I usu­al­ly go with name brand just to be safe.

  10. Final­ly some­one to answer my sim­ple ques­tion … I final­ly received my HNT min­ers and anten­nas . Can I screw my light­ing arrestor (with a female end) direct­ly onto my anten­na (with a male end), and avoid break­ing the run and order two sep­a­rate cables. or dose the light­ning arrestor have to be a cer­tain dis­tance from the anten­na? It looks like that is exact­ly what you are doing and that way I dont have to order a sec­ond cable and break the cable run correct?

    Thanks .

  11. Hi Aaron, yep, that’s total­ly fine to attach the light­ning arrestor direct­ly to the antenna.

  12. Your the best thanks! Its tough to find co ax in my area. Looks like ill have to order them all on line cus­tom mae.

    hey do you know of good place, quick ship­ping to ALber­ta Cana­da that can make up som 440 with N type female end and RP SMR male end at lengths of, 5′ 10′, 15′ 25′ and 30′?

  13. Hi Aaron, hmm, not sure of Cana­di­an sources. Might try call­ing USACoax.com and see if they have Cana­di­an connections.

  14. Hey Nik,

    I have an HNTen­na 3 dBi anten­na (tall, skin­ny one) and am plac­ing it out­side my bed­room win­dow on the 3rd floor of my apart­ment. I’ve read that a 3 dBi anten­na won’t need a light­ning arrestor since it’s 1) not strong enough to send too much pow­er back to the hotspot to fry it, and 2) I’m not hoist­ing the anten­na up a pole 20 feet high­er than the apart­ment roof.

    If that info is inac­cu­rate and a light­ning arrestor is need­ed, is it pos­si­ble to ground the cop­per wire to my bal­cony floor? I won’t have access to drop­ping a 30 ft wire down the side of the building.

  15. Hi Nik, straight donw the line and to the point post, freakin awesome.

    Here are some thoughts from days when we used RS485 as com­mu­ni­ca­tion over long dis­tances in South Africa where light­en­ing was always a challenge.
    — Arrestor as close as pos­si­ble to equipent to min­i­mize the exposed wire becom­ing the next light­en­ing / sta­tis anten­na. Any exposed wire has the pos­si­bil­i­ty of receiv­ing and induc­ing sta­t­ic into the system.
    — Rather run a new ground wire to a prop­per Ground pole — if the ground is not good then not even the fan­cy gasses will stop a sta­t­ic / light­en­ing strike. Its a good idea to have a Ground pole near a rain gut­ter to keep the ground as moist as possible.
    — Buy good well known arrestors, its worth it

    Leon

  16. Hi Mike, well, tech­ni­cal­ly *all* out­door anten­nas should have a light­ning arrestor. Many don’t. I’ll prob­a­bly get sued out of exis­tence for say­ing it, but I would­n’t wor­ry too much about a small anten­na out­side your bed­room window.

  17. Michael Johnson

    Hi Nik, I appre­ci­ate the hon­esty. My biggest con­cern is mak­ing sure my hotspot does­n’t get dam­aged but you seem like an extreme­ly hon­est guy with a TON of expe­ri­ence so I’ll take your word on it. Thanks!

  18. He’s bet­ter off to buy a 5.8 DBI anten­na and mount it in his win­dow indoors instead of a weak three outside

    No ground­ing required and bet­ter range

  19. Hi Nik,

    I plan on putting my anten­na on the side of my roof (about 20 feet high but at the same height as the roof). Like Mike, do you sug­gest ground­ing it since it’s not 20ft about the house? Addi­tion­al­ly, I have a few pow­er lines near my house that are about 30–50 feet away. Would these cre­ate sta­t­ic and pos­si­bly dam­age my miner?

    Thanks in advance!

  20. Hi Octavio,
    I would­n’t wor­ry about sta­t­ic from the pow­er lines. Tech­ni­cal­ly you should ground every out­door anten­na. Prac­ti­cal­ly you’ll see that many peo­ple don’t.

  21. Hey Nik

    I now have 2 or 6 min­ers installed. I wish I had. Clone to do the installs . Anyhow

    Ive been asked a cou­ple time now are Bob­cat devis­es safe. What do they emit. Ive heard RF waves are harm­ful … etc and I can’t real­ly find any­thing that states they are safe oth­er than they are FCC approved .do you have any links or info uiu can send me. 

    Many thanks

    Aaron Ursu­lak

  22. Hi Nik, it may be a stu­pid ques­tion here but bet­ter ask… 🙂 We’ll mount our anten­na on a 6‑storey build­ing and the anten­na will be 5 ft above the roof. The ground­ing of the roof (which is flat) is done with a met­al grid that cov­ers the roof. We are think­ing about con­nect­ing the light­ning arrestor to the grid instead of run­ning our own rod all the way to the ground, which obvi­ous­ly is not pos­si­ble. Just wor­ry­ing that charge already col­lect­ed in the grid may go up to the arrestor and dam­age the equip­ment. I don’t know if this is ? valid con­cern… What do you think?

  23. Good ques­tion. I don’t think so, but I’m not an elec­tri­cian. There should­n’t be any charge col­lect­ed in the grid; it’s ground­ed, right?

  24. Hey Nik. I need anoth­er 10 5.8DBI anten­nas> I can order them from RAK but deliv­ery is way out …!

    Do you know of US supplier?

    Thanks Aaron Ursulak

  25. Hi Nik,
    Have you come across oth­er strong research/opinions against con­nect­ing the light­ning arrestor direct­ly to the anten­na like you did? Do you have the arrestors direct­ly con­nect­ed to the anten­na in most of your setups? I ask because I would like to fol­low best prac­tice once and for all. Thanks.

  26. Hi Ndu,
    I’ve heard from a cou­ple folks that you should con­nect the light­ning arrestor clos­er to the equip­ment being pro­tect­ed. I have ’em con­nect­ed direct­ly to my antenna.

  27. Hi Nik, which “Nex­Tek Surge Guard light­ning arrestor” would be rec­om­mend­ed for an out­door HNTenna?

  28. Hi Eli,
    The out­door HNTen­na has an N‑type female con­nec­tor, so you’d want an N‑type male on one side of the Nex­Tek, then what­ev­er match­es your cable or hotspot on the other.

  29. Nik, I’ve learned a lot from your site. I appre­ci­ate it!

    My orig­i­nal plan was the mount the light­ning arrestors at the base of the anten­nas and then run­ning the cables back in the house…10′, 20′, or 30′ or what­ev­er the length for the appli­ca­tion. How­ev­er, now I’ve heard peo­ple on the AV and Ham radio forums say that since cables can also build up a sta­t­ic charge (not just com­ing in from the anten­na) then sta­t­ic charge won’t nec­es­sar­i­ly be dis­ap­pat­ed out that arrestor as you’d want, and it could just as eas­i­ly go down the cable to the min­er and so this is why you should have the arrestor/ground as close as pos­si­ble to where it enters the house and also as short of a cable as pos­si­ble to the ground rod. 

    I guess you don’t think that is necessary?

    What I’m wor­ried about is that we THINK and HOPE we’re fine with the arrestor at the end of the anten­na but we don’t KNOW for sure until it’s too late and we have damage!

    These were also rec­om­mend­ed to me, which ground the out­er sheath but I assume not the inner wire of the cable. I won­der if this could be a good belt and sus­penders solu­tion since I’ve already pur­chased the cable and arrestors to do it as you said, but these could also dis­si­pate sta­t­ic in the line clos­er to the build­ing entrance.
    (Not sure if links are allowed but here it is if so)
    https://www.solidsignal.com/installation/grounding-supplies?custitemsg_brand=Times-Microwave-Systems&pricelevel5=0.31to31.97

  30. Hi Brad,
    That all looks good, and you can def­i­nite­ly put the light­ning arrestor clos­er to the gear side (away from the anten­na). I’ve always used super short anten­na cables so a short ground wire has­n’t been an option, but it’s a fine way to build it. Let me know how it goes with the Sol­id Sig­nal stuff, looks neat.

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