[ADXA] Antennas & lightning

Sun Jul 13 15:54:17 EDT 2025

I’ve had similar problems with USB cables so I pull them too
EJ

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________________________________
From: adxa-bounces at mailman.qth.net <adxa-bounces at mailman.qth.net> on behalf of Jussi Eloranta <eloranta at aa6kj.hopto.org>
Sent: Sunday, July 13, 2025 2:34:12 PM
To: 'ADXA' <adxa at mailman.qth.net>
Subject: Re: [ADXA] Antennas & lightning

Hi,

Thanks everyone for sharing the info! Very helpful!

Just to add that the network connection to my station is through optical fiber (two modems and a short piece of fiber) just to make sure there is no electrical contact. The station side modem gets disconnected from AC whenever the station is disconnected. My shed is made of metal (Faraday cage) and I must bring the net in using ethernet cable (from outside WIFI repeater). And my QTH is located high up, so lightning strikes are frequent. That reminds me, I am told that we are "hill people" - I guess that is a nice way of saying hillbilly :-)

Since my station ground is bonded to the AC ground, I will add a connector that allows me unplug the ground easily as well. This is the likely reason my K4 got hit. And Adding more copper for better ground is on my TODO list now as well. As usual, there is no free lunch :-(

But there is not much that can be done if it is a direct hit. In such case I just hope that my shack does not evaporate...

All right, now it is time to pack!

Jussi (aa6kj)

ps. Bill, if I run into Martti, I will certainly say hi to him from you.

On 7/13/25 13:12, k5ur at aol.com<mailto:k5ur at aol.com> wrote:
I've had serious damage from lighting over the years and some of you will remember some of my stores.... holes in the wall, busted walls sheetrock, ceiling caving in and endless equipment damage.

I  have a massive ground system under these towers. Miles of wire, yet sometimes damage from a direct hit is hard to mitigate.

I recall one time when lightning hit a tree just on the other side of the wall in the radio room. I suspect it hit one ofthe towers, too. The 200 ft tower is lightning rod. Anyway, I had a pole peg transformer in one of my homemade power supplies sitting against the wall, so there was probably 8 feet separating the transformer and the tree. Everything was disconnected yet the induced voltage on that pole peg caused an explosion in the radio room. Arcs everywhere.

I disconnect every line when a storm is coming. Nothing is connected, not even the ground. Nothing. Back in the day with tube radios, you could keep the ground connected but not today with these fancy radios. My radios are as if they are sitting in the floor in the middle of the room with nothing connected to them.

All coax lines and rotor cables, disconnected, all cables to radios, amps, accessories, all disconnected and nothing attached. And that goes for the AC lines, too. Living at the end of a distribution line invites the stuff to travel to a termination. I've had AC outlets blown to bits leaving a hole in the wall.

Disconnect everything!

73,
Rick - K5UR

On Sunday, July 13, 2025 at 10:23:18 AM CDT, J Ferguson via ADXA <adxa at mailman.qth.net><mailto:adxa at mailman.qth.net> wrote:

Jussi,

Lighting is a fickle beast. The energy potential in lighting far exceeds the rated handling capability of polypahsers, and despite our best efforts to ground and control the path of a strike the risk of it finding it’s way to my equipment is too great.
I always disconnect my attendants and radios (when I am in a position to do so) to reduce the likelihood of a direct of nearby strike causing equipment damage. My antenna coax is place the open end in plastic lawn and garden waterproof extension cord covers when disconnected. This provides me (perhaps a false sense of security) with trying to make sure the antenna and coax being in a float state for the energy of a strike to travel. It also helps to keep me from having the coax accidentally being kicked or moved and creating a possible ground path.

What I use for covering the coax: https://www.lowes.com/pd/Twist-and-Seal-0-5-ft-Plastic-Cord-Organizer/1000132801

Sounds like your shack is outside your home, have you thought about setting up a remote disconnect system?

Others thought’s on this topic?

73,
J Ferguson
N5LKE

On Jul 13, 2025, at 9:58 AM, Jussi Eloranta <eloranta at aa6kj.hopto.org><mailto:eloranta at aa6kj.hopto.org> wrote:

Hi,

The weather has been pretty rough at least here in the NE corner. Lightning on and off on almost all days. I have been running back and forth between the house and the shack disconnecting and reconnecting antennas & power. The weather forecasts have been pretty useless with these storms. They appear quickly and are gone quickly.

My question is as follows. With proper grounding and polyphasers on coaxes (+ surge protectors on power), do you guys disconnect antennas & power during storms? In CA lightning is rather rare and this was not an issue over there. I feel that here I have the radios disconnected most of the time! And my K4 died mysteriously during a recent storm with only the ground connected. It is possible that lightning can get in through the ground too... Fortunately Elecraft was pretty quick to fix it.

Jussi (aa6kj)

PS. I am headed to Finland to attend the annual SRAL summer meeting. Hopefully the weather is calmer there... Great to see some old friends over there.
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