Non UL Listed UHF Lightning Arrestors for Ham Antenna Feed - Page 1
Forum section: electronics / rf-microwave

author: gridleak
author_rank: Contributor
timestamp: February 13, 2018, 03:30:03 am
content: Seems to be difficult to post on the ham forums without a call sign or pay subscribing to eham so here I am. I'm building my antenna installation. Although I can't afford a completely populated Single Point Ground Panel (SPGP) I will have a ground panel bonded to my ac service with a lightning arrestor for the antenna coax feed. There seems to be just two companies catering to hams using PL259 connectors; L-Com and Polyphaser. Neither of these companies have UL listed arrestors. The CE certification they both carry is not recognized by the US National Fire Protection Association (NFPA). Therefore installations using these devices are in violation of the National Electrical Code (NEC) which is published by the NFPA. I'm worried about being able to collect on an insurance claim for fire caused by a lightning strike using an unlisted device. Is there anyone else out here who has had the same concern, and has come up with a solution?

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 13, 2018, 04:43:13 am
content: Any reason for using PL259? It's not a particularly good RF connector.

author: gridleak
author_rank: Contributor
timestamp: February 13, 2018, 05:57:52 am
content: N connectors for RG8, LMR400, and RG213 are superior, but Polyphaser and L-Com don't have any UL listed arrestors for that connector either. Since CATV, satellite TV, and OTA represent millions of installations using RG59, RG11, and RG6 coax we find plenty of UL listed F connector compatible ground blocks. Large, 50 ohm coax used by hams and commercial broadcasters represents a very small market, in comparison. It doesn't pay to get UL listing. Hmm, I guess I could use RG6 or RG11 and then I could get UL listing devices. It's just that as I'm a new ham I purchased and installed a precut multi-band "mystery" dipole that is designed for 50 ohms. When I learn more, I'll see if I can change to 75 ohm video coax and match it to my antenna. The only downside to video coax is you can't run high power levels through it.

author: LaserSteve
author_rank: Super Contributor
timestamp: February 13, 2018, 02:55:36 pm
content: Call UL, after looking up the UL Listing Classification for coax arresters and ask for a list of approved products. Ask for a list of approved units. If you can't get one, document that you have done your due diligence, could not locate one, and install a good one anyways..Steve

author: LaserSteve
author_rank: Super Contributor
timestamp: February 13, 2018, 02:59:09 pm
content: Also call Times Microwave Inc... They make the whole arrester panel, so they have to have some approvals or know who does.I hate PL259, I'd ditch that connector if you can..This is worth a read...https://literature.hubersuhner.com/Technologies/Radiofrequency/Lightningprotection/Steve

author: kb0nly
author_rank: Contributor
timestamp: February 13, 2018, 07:17:12 pm
content: Ok first off let me comment on the fact that you should be installing a separate ground rod for your antenna feedlines, i know this will cause some to argue bonding and such with the AC service ground, but you can't rely on tying your lightning protection to your incoming water line as most AC services use and call it a day. Install a ground rod, install a entrance panel for the coax, and ground to that.DX Engineering makes a nice grounding panel, its an outdoor rated DeMarc box with an aluminum panel in it that you can mount your arrestors to. I have had this setup on my tower for almost 10 years now. As for the arrestors themselves, i use PolyPhaser, and every commercial site i have been to in the last 15 years around here have PolyPhaser protecting their equipment. They are very good arrestors.As for UL listed, I don't see how this is an issue. Considering how many of these are in use on commercial sites, and how many are in use in home installations by ham's, the last thing i am going to worry about is UL listing on a device. What you have to understand is that in a direct strike all bets are off, i have seen commercial sites with the best protection that can be bought on a commercial budget not survive a direct strike. What your trying to protect yourself from more then anything is nearby strike energy and static charge buildup on the antenna system, which is especially a problem in the winter time but also in dessert climates.Most hams use the IS-50UX or IS-50NX, U for UHF, N for N connector. As to the comments about the UHF connector, aka PL-259, its perfectly fine for HF and VHF use, its been in use for longer then some of these hams have been alive, and will continue to be. You mentioned a dipole, you don't need an N connector for HF use, total and complete nonsense overkill. There is a lot of guys using F connectors at HF and feeding them with RG6 along with a matching setup to use the cheaper coax, its not an issue. Now if your going above VHF and operating in the UHF band or higher then by all means go with the N connector, but your not going to see a huge difference at VHF and below, total horse hockey to say you need N connectors.You can make a grounding panel pretty cheaply, i have built them by buying scraps of copper sheet from the local junkyard and drilling and tapping mounting holes for the PolyPhaser's, then a good ground and its all done. If your worried about an insurance claim due to a lightning strike then talk to your insurance agent, thats what i did. Most of them don't have any clue what your talking about, i finally had to pose the question as if my tv antenna or a satellite dish was struck, as thats about all they can understand antenna wise. Long story short the agent agreed that adding lightning protection was a reasonable attempt at securing the installation against failure, and if it ever happens it will be covered as i did my due diligence.

author: dmills
author_rank: Super Contributor
timestamp: February 14, 2018, 12:23:18 pm
content: Got to admit, I use used automotive spark plugs mounted in a bit of aluminium channel, simple, cheap and good enough to catch the energy from a near miss (Get the ones that have a screw connection for the HT lead, easier to connect to).At HF you are not going to get much radiation from the few inches of wire thus exposed, and you just leaver the gap open until it stops breaking down at whatever power you usually run.If you are running open wire feeder then spark plugs tapped into a bit of metal and bolted to suitable bits of the tower and any other handy grounding point provide multiple cheap over voltage gaps distributed along your feeder.A direct hit will still slag things, but that is the nature of lightning.Regards, Dan.

author: jgalak
author_rank: Regular Contributor
timestamp: February 15, 2018, 01:27:37 pm
content: On a separate part of the OP: I'm reasonably sure that not using UL-listed a restoration won't invalidate an insurance claim. I'd check with an insurance broker or attorney in your state, but I've never heard of a denial based on "doesn't meet code".

author: daedalux
author_rank: Contributor
timestamp: February 21, 2018, 03:36:43 pm
content: The protecting device in all this kind of rf arrestors is a white ceramic capsule with one metallic disc on each side and with the leads. It has a really small capacitance and starts conducting somewhere between 500 and 1000V. This components have a brand and certification, and are cheap, like a couple of bucks for a SIEMENS one for this application so perhaps you should get them and competently install it on the base of the antenna. The perfomance of the ground connection is much more of an issue and will affect your station regular perfomance as well so focus on that.