External antenna and lightning

[dc8-63]

Hi,
I'm about to put up an AOR SA7000 antenna (max 1.8 metres tall) on top of a 2 metre pole on the outside of a single storey house, running the coax inside to the scanner room. Do I need to earth/ground the setup in case of lightning? Any advice on how would be appreciated.

[pagertones]

if you have it earthed it would be a fantasic idea im sure lightning would not be a big factor in a 1.8m antenna but "Better safe than sorry"

[Scannersplitterguy]

Ideally, you should have a copper earth rod driven at least 1metre into the ground, as close as possible to the antenna mast. Connect the rod to the mast with a heavy gauge braided earthing strap.
Both of these can be purchased from a trade supply outlet like Hayman's or Lawrence & Hanson.
They can also supply the correct cable clamps etc.
Driving a 1 metre rod into the ground isn't easy unless you have very sandy soil, so be prepared to work up a sweat!

I have an earth rod that is 5.5 metres long....it earths my entire colourbond roof and antennas.
A large hammer drill with a special attachment was used to drive three 1.8 metre rods into the ground (each rod screws into the next to form one continuous length).

[hotmetal1000]

For 4m I wouldn't be too worried about it, unless your block like mine just loves lighting strikes. Touch wood none of my antennas have been hit yet and I'm a lot further up than 4m's.

[rochedalescan]

I know you can get Lightning arrestors that clip on to your connectors for uhfcb and amateur maybe something could be done for scanning ? The earthing method would be a less expensive way of doing it though for sure.

[AIRMAN]

Always a risk of storm and strikes are outside antennae.

Some install their antenna inside the roof cavity which should protect it from lightning strikes, however if you have metal faced roof sarking inside the roof tiling, then forget about it. I don't think this method would work with a Colorbond roof either.


Be very aware of lightning!
Years ago I was camping in a remote part of the planet and needed a long wire antenna for my shortwave radio. I had a 30m length of plastic coated copper wire and launched it over a big tree nearby with the help of my fishing rod. Connected it up and it worked fine until lightning hit the tree, traveled down the wire and incinerated my rig and gave me one hell of a fright. Luckily I wasn't using the set at the time!

[RADIOHEAD]

Even with the mast earthed, there is no guarantee that ALL of the energy from a lightning strike will go where you want it to. You may still develop a dangerous EMF across the antenna socket, enough to kill your radio. Whilst the height you have specified is low, as noted by others, if you are concerned you should earth your mast for safety's sake, and also install a quality lightning arrestor in line with your coax. You would generally bond the arrestor to your earthing system right before the coax enters the building.

[alinco21]

unplug the coax from the receiver, throw the coax out the window.

Works every time.

[Ronsta]

unplug the coax from the receiver, throw the coax out the window.

Works every time.

This is the only method that is 100% effective. Earth straps, lightning arrestors etc are great if you are not home during a storm, and offer some protection.

Ronsta

[Spectre]

I recall as a child my parents disconnecting the TV antenna from the set during storms, even if grounded through the roofing and down pipes etc. the equipment can still sustain damage to the electronics


The Ham operator in this YOUTUBE clip learnt the hard way by disconnecting the cable at the wrong end...