WA Radio Scanner Users' Group

Anybody using lightning protection on their elevated coaxes attached to their lovely expensive equipment that wouldn't like eleventy trillion volts attacking it? Commercial? Home-made? Unplug if you remember to?

robbage wrote:Anybody using lightning protection on their elevated coaxes attached to their lovely expensive equipment that wouldn't like eleventy trillion volts attacking it? Commercial? Home-made? Unplug if you remember to?

I've used gas arrestors before. Not cheap and they need a well thought out earth system but they do the job for anything up to a direct strike to the antenna.

I've got a pile of gas arrestors from some de-commissioned equipment. They were installed on some STP data cables. They are a clip in thingy with the arrestor part snapping into a holder. The holder has two solder tabs.

I agree the earthing would have to be done right. Putting one directly from centre of the coax to shield wouldn't achieve much, I guess. Did you have them at the antenna or the equipment end? Was there much effect on signal, swr etc? I can get a pretty good ground to the mast. What concerns me is that grounding the mast might make it a more attractive path.

After seeing those pics of the house that had a strike a couple of weeks ago, I doubt anything will save your gear with a direct hit

I have used Novaris, RFI and another brand whose name escapes me at the moment.

All much of a muchness - I wouldn't bank on anything saving radio gear from a direct hit, but may be of value against EPR's. I guess you will never know if it has been worth the investment unless you come home one day and everything else is fried.

Interestingly I've seen a surge diverter systems that has a counter which totals the number of direct hits an installation has but never known of them to be installed.

robbage wrote:I've got a pile of gas arrestors from some de-commissioned equipment. They were installed on some STP data cables. They are a clip in thingy with the arrestor part snapping into a holder. The holder has two solder tabs.

I agree the earthing would have to be done right. Putting one directly from centre of the coax to shield wouldn't achieve much, I guess. Did you have them at the antenna or the equipment end? Was there much effect on signal, swr etc? I can get a pretty good ground to the mast. What concerns me is that grounding the mast might make it a more attractive path.

After seeing those pics of the house that had a strike a couple of weeks ago, I doubt anything will save your gear with a direct hit

Are these the same as the old Telecom/PMG arrestors that were on phone lines? We've got a heap of them around somewhere. Would it be practical to use them on coax?

Toottoot wrote: Are these the same as the old Telecom/PMG arrestors that were on phone lines? We've got a heap of them around somewhere. Would it be practical to use them on coax?

Since they were designed for phones, their high frequency response will probably suck. So no, I wouldn't use 'em.

Toottoot wrote:Are these the same as the old Telecom/PMG arrestors that were on phone lines? We've got a heap of them around somewhere. Would it be practical to use them on coax?

Possibly. I think it would be a pain in the butt. Shield to ground could be done.

vk6hgr wrote:Since they were designed for phones, their high frequency response will probably suck. So no, I wouldn't use 'em.

This was my concern. At higher frequencies, they probably act like a capacitor

Toottoot wrote:I have used Novaris, RFI and another brand whose name escapes me at the moment.

All much of a muchness - I wouldn't bank on anything saving radio gear from a direct hit, but may be of value against EPR's. I guess you will never know if it has been worth the investment unless you come home one day and everything else is fried.

Even then you couldn't be sure it wasn't just dumb luck. Lightning is a strange beast.

Toottoot wrote:Interestingly I've seen a surge diverter systems that has a counter which totals the number of direct hits an installation has but never known of them to be installed.

A sparky I work with says that Western Power use strike counters a lot to gauge the number of strikes on power lines and poles. Makes me wonder how often this happens. I've got surge diverters at work but they're just a black box that trip a breaker

I'm a sparky and used to maintain some power lines up north. The main fault would be the line would get hit by lightning and crack the insulators on the pole. It would only be a hairline fracture and you would have to drive the entire length of the line to spot the damaged insulator. That was until we installed surge current indicators which narrows it down a bit.

Ive seen a lot of surge current indicators on the power lines around on the SWIS and it looks like they talk back to the WP control centre through the telemetry network.

Ive also seen radio equipment that people describe as 'would fail as soon as it smelt lightning coming', but installing surge protection on the power side fixed it.