Antennas/Lightning Protection Recommendations

[N7SC]

Here are the existing facts:

My location is roughly "in the middle of nowhere," in Florida (flat terrain, no mountains to worry about), and I would like to be able to clearly pick up FM stations up to 100 miles away.

I have a 50 foot steel tower attached to my house, a great place to mount an FM antenna for good reception. It is obviously a great lightning target too. There is already a very big TV-FM antenna/non-functional rotor on top of it. The antenna has an amp and an FM trap on it.

I live right on the edge of an area known as "Lightning Alley" in Florida. My house has been hit several times in the 11 years I've been here. Ditto my neighbors' homes.

Given that I'm going to buy a McIntosh MR77 or MR78 tuner in the near future, would like to give it as good an antenna as possible, while protecting it from being incinerated by lightning coming down the antenna cable, what would you recommend for both an antenna and protection?

[merrylander]

Even though both my TV and FM antennae are in the garage attic I have ground blocks on the RG6U cables connected to the main ground of the electrical system. The main TV and Stereo are on an APC surge protector and I installed a lighning arrestor in the 200 Amp power panel years ago when the house was built. My PC and my wife's PC are on APC uninterruptible power supplies that work like a charm.

Is your tower mounted on the house or the ground? No matter where it is mounted I would put a really solid ground connection to the tower structure itself. Other than that disconnecting everything during a storm is about the only sure thing, but even that is no guarantee as I have seen some strange effects of a lighning strike on a house.

Rob

[OvenMaster]

My antenna mast is only 25 feet off the ground, and this summer we've had some nasty storms. Every time the forecast calls for thunderstorms, if I'm home I disconnect EVERYTHING-- rotor, antenna, power cords-- as soon as I see or hear lightning. If I'm going out, I disconnect it all just in case the weatherman is right.

I have a cheapo surge suppressor and line filter for the stereo gear, just in case the power cuts and is restored, and for spikes and surges (yes, I should replace it after 6 years...). I also had to put in a new ground rod after the riding mower yanked out the aluminum ground wire from the buried rod, which I didn't feel like digging for. My ground rod is used for both the mast and the RG6 grounding block.

Tom

[hpsenicka]

Grounding an antenna tower is critical, and using an inline grounding block is a good idea as well, but these are not to be confused with true "lightning arrestor".

I suspect most folks consider a proper lightning arrestor overkill for a home installation, but it would be worth considering if you are in high risk area for lighting.

PolyPhaser ( www.polyphaser.com ) makes excellent lightning arrestors for a variety of radio applications.... they are considered standard equipment for outdoor WiFi antenna installations.

[markthefixer]

Actual lightning protection depends on good grounding, heavy wire, NO SHARP BENDS IN THE GROUNDING and attention to induced currents in nearby cables...

Buddy did work with equipment on 500 foot radio tower in the Houston area...

Lots of other considerations too....

this will get you started (http://www.lightningrod.com/manual5_how.html)

One thing to remember, I had a lightning multiple strike lightning fork a few years back hit a tree 90 feet southwest of my antenna, and also 75 feet north-north-east of my antenna,MISSING my antenna.... see the "protection effect in the link.... my experience PROVES it works.

For mine safety in blasting from powerlines, when thunderstorms are in area of mine there MUST be a FIFTEEN FOOT gap between the blasting wires and the power wires and the blasting wires shorted and grounded.

[JimmyNeutron]

Nothing....NOTHING will protect your equipment from a direct lightning strike. If lightning hits your antenna, nothing will keep it from hitting your equipment too. I'm a firm believer in hi dollar surge protectors like Tripp-Lite and Monster Cable and Adcom. On a few occassions in the past lighning has hit "near" my house (trees actually) and it usually finds it's way thru the rebar in the foundation to the lines coming into the house (power, cable, phone) and then to all attached equipment. The surge protectors AND equipment were history. I lost a Plasma just 3 years ago to this incident with an $800.00 Monster Cable surge protector attatched. Surge Protectors are just that - "surge" protectors, not lightning arrestors. If you live in lightning alley, unplug your equipment. I wouldn't chance it.

[EddyR]

I use to live in Oldsmar Fl just north of St Pete and I had a 30 ft tower.As I turned off my equipment I discounted the antenna. My neighbors told me they saw lightening hit my tower several times but I never had any damage. My tower was on the ground and I had four ground radials going out from the base. I could get from south Georgia to south Florida with no trouble . I was using a Radio Shack 10 element FM Yagi.When the skip was running I could hear Europe
EddyR