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Author Topic: How High Is Your Radar Box Antenna? Have You Ever Had Trouble With Lightning?  (Read 5916 times)

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Johnn

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Many Thanks
John-
Johnn -

Fenris

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There's a lot of misinformation about the effects of lightning.

An actual lightning strike is a massive event, even with lightning conductors and grounding the chances are that most if not all equipment will be destroyed.

The real purpose of a lightning conductor is to reduce the electric field due to static electricity and thus prevent a strike occurring. To some extent an antenna mast will do this as it will be electrically at somewhere near ground potential especially if there is a coaxial cable that itself is grounded.

If static builds up on an antenna it may be able to discharge through the receiver unless actions are taken to divert the static voltage/current. That's what the RB front end does on new build boxes, it uses a protection device that allows current to flow if the voltage rises to a certain level. Sometimes even this can lead to damage, the SAW filters in the front end have transducers with very narrow metal connections etched on the filter substrate and these will be blown off the surface if excess current flows.

You may find that it is better to use an antenna where there is DC connectivity between the element and the ground side of the connector. If you look at the threads on antennas you'll find some more information there.

Johnn

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Very Informative, Thanks Fenris
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Deadcalm

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We're 450 metres above sea level, on the summit of a hill, and the antenna is above the roof pitch, and about 20 feet from the ground.  We get a lot of thunderstorms around here, and frequently lose power.  I disconnect the antena in thundery weather (I use a Boltek lightning detector to get warning of close activity), and hope for the best.  No problems, yet...

DC
Go around, I say again go around...

sterigia

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i have had 2 direct hits in my place in 20 years with catastrophic events, all electrical wires and telephone wires evaporated along with all all appliances connected burnt.
i live in a small town 255 metres above sea level, surrounded by hills to the north and west, my home is in effect higher than tha surrounding houses but  it is not really relevant seeing how i was struck, and there are much higher houses, the same day the bell in the chuch was hit , it is about 200 metres from me and in a much  higher  tower, it was broken and we are awaiting a replacement from a foundry.
 both times the lightning came in via the telephone wire from a pole i have near my home that brings the cable into my house so the phone company, with some coaxing (legal) has payed nearly alll damages.
seeing the situation with the last hit in august this year i have since then had a lightning rod put up in the highest part of the roof hoping that lightning will strike that instead, the alternative was to construct  a faraday box with thick copper wire all around the house, which was not really feasible, i will if i get another strike. anyway all my antennae are now grounded, today i had the work done as i got a shock from an antenna the other day plus they are considerbly lower than the roof , about 2 metres and tucked into a corner of my house. i must compromise between safety and performance.
that's about all, i think, i too have a lightning detector now and it is a pricy toy, necessary, seeing that the sky was almost clear when struck the second time. the manufacturer says the rod works making hits more probable on the rod itself. i don't know, there is much confusion except when you are on the receiving end :-).
ciao
frank
« Last Edit: October 31, 2009, 05:48:22 PM by sterigia »
ciao.
frank

sterigia

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because i did not see this one first, obviously, pat. but why complain about it? what is the meaning of the complaint and above all what are the reasons behind your complaining?  the topics are a bit different from my point of view.........................
frank
« Last Edit: October 31, 2009, 08:28:09 PM by sterigia »
ciao.
frank

Deadcalm

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Ignore him, sterigia, he hasn't quite got the hang of forum behaviour, yet.

DC
Go around, I say again go around...

sterigia

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ok i'll let this pass and others from him. i won't be drawn into a flame for no good reason
ciao
frank
ciao.
frank

AirNav Support

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We have removed his post and he has been warned.
Contact Customer/Technical support via:
http://www.airnavsystems.com/contact.html
[email protected]

sterigia

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ok thanks but really it was not worth the trouble , i would have ignored the thing, anyway again thanks
ciao
frank
ciao.
frank

juangelb

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Hi People
I am at 2400 feet ASL and have two non grouded antennae on top of a 15 floor building,
I vever disconnect somthing, no matter what the wheather is.
Only once that a thunder striked just overhead, harware conected went red...
I thought... well, one of my RBs went away .... But I disconnecter and reconeccted the USB cable, at it was not needed neither to restart RB.... Hardware connected went again to green.
Pictures follows og antennae... the white vetical PVC .. homebrew :

Best regards.
« Last Edit: November 01, 2009, 10:39:09 AM by juangelb »