What are most of you doing for Lightining protection on these antennas. Mine is out doors and having one heck of a storm. I ground my mast and cabling, but I do not see any Lightining Arrestors for our Freq band.
Thanks for any advice.
Sparkie
My roof has a pretty big peak on it, so I just put it inside the rafters. Seems to work well.
Thanks for the heads up… One on order, be here tomorrow.
Mine is going on my Roof and will be 10 feet above the peak… BTW, a RF Lighting Strike and Static can hit inside. These things are good insurance policies.
These are good for static protection only. It will protect your equipment from the static generated in you antenna & cable due to atmospheric conditions like wind & charged clouds overhead, but cannot protect anything if there is a direct lightning strike.
You need a proper lightning protection system if you want to minimize damage to your BUILDING & EQUIPMENT from DIRECT LIGHTNING STRIKE
My antenna mast is grounded to an eight foot grounding rod per local building code.
I’ve noticed that hospitals are particularity protected from lightening strikes. I suppose that’s because of all the O2 lines running through them along with sensitive patient monitoring equipment.
I am aware of grounding all to well… And I have seen my share of Lightning strikes over the years. My basic question was which arrestor that was a good one to use, not if I wanted to install one. I have been in Amateur for a great many years, working Avionics in the Airline industry, and I have literally seen antenna’s blown completely off aircraft. I saw one plane that took such a lightning strike that it shorted out both generators and the entire electrical system and to boot shorted out his backup power. All he had at night was a Hand Held Aviation Nav/Com radio (before the days of Cell Phones) an altimeter and compass at night. Lucky for him, he was able to get it down with no further incidences… As if that was not enough for one flight. In Amateur Radio I have seen towers struck and buckled…
Like I said it was not a question of if but rather which!
And just for the record… I earned my nick name as a Electronics Bench Tech at the time, and it was all because of a Floating Ground that was not Floating! 
Sparkie
Sparkie is the nickname for all electricians in Australia.
Perhaps another viable option.
The one I have now is very similar, except it is 3GHz model, showing below
http://www.l-com.com/surge-protector-n-female-to-n-female-bulkhead-0-3-ghz-230v-lightning-protector#
http://www.l-com.com/multimedia/datasheets/DS_AL-NFNFB-_.PDF
I have also ordered a few gas tubes as spare for the inevitable…
Sparkie
How much power in a bolt of lightning?
Lightning bolts carry from 5 kA (5,000A) to 200 kA (200,000A) and voltages vary from 40 kV (40,000V) to 120 kV (120,000V). If we take average values, say, 100 kA and 100 kV, this bolt would carry power P as calculated below
P = 100×1000 A x 100x1000 V
= 10,000,000,000 Watts or 10 billion Watts.
Some animated photos of Lightning Strikes
High-speed photography showing different parts
of a lightning flash during the discharge process.
https://upload.wikimedia.org/wikipedia/commons/b/b6/Lightnings_sequence_2_animation.gif
A downward leader travels towards earth, branching as it goes.
Lightning strike caused by the connection of two leaders,
positive shown in blue and negative in red
.
Lightning Strike of Starwars’ Emperor Palpatine 
http://static7.comicvine.com/uploads/scale_super/11113/111137054/4067453-mace+vs+palpatine.gif
Lightning, striking the rebar, has been known to blow big chunks of concrete from the surface of a runway.
Just remembered I forgot to post one photo which I use regularly, and is relevant to lightning
Zeus, the Greek God of Electricity, ready to throw a Thunder Bolt
Gas discharge type lightning surge arrestors are the best protection for your receiver system.
Let’s not forget that, historically, people used rooftop and mast mounted TV antennas, before the advent of cable TV. In my 57 years, I cannot recall one instance of a TV antenna being struck by lighting in any of the 6 states and two countries I’ve lived in. ALL of the states are in what is considered “Tornado Alley” and endure countless violent electrical storms at two seasons a year.
This is not to say that it doesn’t happen. I personally have had two strikes the destroyed two different radio shacks. One in 1980 and the other in 1995. One a 11m Ringo at 40’ , the other a 2m Ringo at about 25’. Both times the strike left evidence in the way of a melted hole in the aluminum on the vertical radiator of a “Ringo” type antenna and destroyed equipment in the shack. That is, coincidentally, a type of antenna that is uses a directly shorted gamma match. In other words, there is a direct short to ground from the radiator to the base and subsequently to ground through the metal mast.
To put this in context, I’ve had CB and ham shacks with fairly large antennas of various types running for years with no problems from lighting strikes. It’s just not very likely you will take a hit.
On the other hand, I’ve also had a couple of receivers being rendered “deaf” and in need of replacing the front end RF amp as a result of a nearby strike surge or static buildup on a long wire. Hard to tell which was which. I just know there was a storm and the next morning my stuff was broken. My bad for not disconnecting the antennas.
The chance that you might have a direct strike on a very small outdoor ADS-B antenna mounted on your roof peak or eave or even 25’ pole is infinitesimally small. There are just too many other larger metal structures around the neighborhood, generally speaking, unless you have the only three story metal roof in a ranch style Lego home neighborhood. The chance you might get dinged by a side feeder from a nearby strike is extremely, extremely small.
The chance that you might have front end damage from static buildup on a plastic or fiberglass radome ADS-B antenna is small to fairly likely, depending on your setup. Better safe than sorry. Put in the gas discharge surge protector and ground it well. Even if it costs a few bucks more than the dongle.
Best protection is always defined by what harmlessly absorbs that energy. No protector does that.
Best protection is a hardwire that connect lightning on a harmless path to earth. Ben Franklin demonstrated that in 1752. It has not changed. Either lightning takes a path to earth that is destructive. Or it has a better (ie low impedance) connection to a superior earth ground electrode. On a path that does not damage the conductor.
Some wires cannot connect directly to earth (ie AC, antenna, telephone). So a protector does what that hardwire does better. A protector is only as effective as the quality of and connection to (ie low impedance) single point earth ground. Protectors are only connecting devices. Protection is the earth ground.
Low impedance is critical. That means the hardwire must not have sharp bends. Must not be inside metallic conduit. Must be as short as possible (ie less than 3 meters). Must connect to the same earth ground used by all other ‘protected’ conductors.
A protector is simple science. It must be robust enough to conduct a direct lightning strike without damage. Art of ‘protection’ is the earthing. Single point ground is essential. Other factors apply that address both conductivity and equipotential.
Bottom line - a protector is only as effective as its earth ground and connection to that earth ground. Worry less about the protector and more about what harmlessly absorbs hundreds of thousands of joules.
SOURCE:
How to Protect Your House and Its Contents from Lightning:
IEEE Guide for Surge Protection of Equipment Connected to AC Power and Communication Circuits
IEEE = Institute of Electrical and Electronic Engineers of North America.
NEC = National Electrical Code of USA.
CEC = Canadian Electrical Code.
1.1 Damage from Lightning
People generally think of lightning damage as what happens at the point where a cloud-ground stroke terminates on a tree, structure, or elevated wiring. This is generally called a lightning strike. Unless the struck items are protected from lightning, the results of the strike are often visible and lasting. But the lightning current pulse continues into conductive parts of thestructure, cables, and even underground wiring and pipes. Because the initial lightning impulse is so strong, equipment connected to cables a mile (1.6 km) or more from the site of the strike can be damaged.
Figure 2 shows four ways in which a lightning strike can damage residential equipment, in order of decreasing frequency of occurrence. The most common damage mode shown in Figure 2 (labeled 1) arises from a lightning strike to the network of power, phone and cable television (CATV) wiring. This network, especially if it is elevated, is an effective collector of the lightning surges. The wiring then conducts the surges directly into the residence, and then to the connected equipment. While not shown in Figure 2, lightning can also travel through the ground (soil), reaching underground cables or pipes. This is another
route for lightning to come into a building, and can also damage the cables.
The second most common mode (2) shown in Figure 2 results from strikes to, or near, the external wiring network common to most suburban and rural houses. Air conditioners, satellite dishes, exterior lights, gate control systems, pool support equipment, patios and cabanas, phone extensions, electronic dog fences, and security systems can all be struck by lightning, and the lightning surges will then be carried inside the house by the wiring.
As shown in Figure 2, lightning may strike nearby objects (trees, flagpoles, signs) that are close to, but not directly connected to the house (mode 3). In this situation, the lightning strike radiates a strong electromagnetic field, which can be picked up by wiring in the house, producing large voltages that can damage equipment.
Finally, Figure 2 shows (mode 4) a direct lightning strike to the structure. This type of strike is very rare, even in high-lightning areas. It can severely damage a structure without a lightning protection system (LPS), and will generally damage most electronic equipment in the house. The structure damage can normally be prevented by a properly installed LPS of Faraday rods and down conductors, but the LPS alone provides little protection for the electronic equipment in the house.
1.2 Enhanced Protection against Lightning
The NEC/CEC allow for increased protection in high-lightning areas by the optional installation of the following:
- A lightning protection system (LPS);
- Surge protectors on the AC power wiring;
- Additional surge protectors on signal wiring;
- “Supplementary protection” (also called “Point-of-Use” protection) at the equipment to be protected.
Figure 4 shows schematically how the first three above are installed.
Although the lightning protection system is the most visible improvement, it is only useful in the extremely rare direct strike scenario, such as in mode 4 of Figure 2. The basic elements are shown in Figure 4. The lightning strike attaches to the tip of the air terminal, and the lightning current flows via the down conductors into the lightning ground system, which is bonded to the building ground. Properly installed systems should be undamaged by even the largest recorded strikes. They should, however, be inspected periodically to assure that mechanical damage has not occurred.
The design and installation of the lightning protection system is not described by the NEC, but by a related document, NFPA 780-2004. Fortunately there has just been a major recent revision to this code, with strong improvements, especially in requirements to install surge protectors to protect the electrical and electronic equipment inside the house. The new code recognizes only passive strike-terminating devices such as metal rods and heavy wires.
AC and signal surge protectors at the building entrance (items 2 and 3 above) serve similar purposes. They collect the major part of the lightning surge currents coming in on external wiring, and direct them harmlessly into the building ground. They also limit the surge voltages that get inside the building, and greatly reduce the burden on the point-of-use protectors, at the equipment.
The effectiveness of this protection system depends on the integrity of the building wiring. A good surge protection system installation should include testing of all the receptacles to be used, for correct connection of the line, neutral, and ground. This should be done using a tester which can detect interchange of the neutral and ground connections, a common problem. Incorrectly wired receptacles can often appear to function normally, but may not allow point-of-use protectors to function properly.
Most new houses are built with power, phone, and CATV entry points close to one another. That is very desirable, and makes it easy to mount the AC protectors and signal protectors close to the main building ground point (Figure 4).
If wiring comes into a building at many different points, it is much more difficult to get proper protection against lightning surges. Even if surge protectors are installed at these alternate entry points, the long ground wires running back to the main building ground greatly reduce the effectiveness of the protectors. In high-lightning areas, where lightning protection is a major concern, it is worth routing as many AC and signal cables as possible past the building power entry point, to
facilitate good grounding for protectors and cable sheaths.
The coaxial cables carrying CATV signals and small-dish (DBS) satellite signals are often the path for damaging lightning surges to enter the building. For CATV cables, the code-required bonding of the sheath to the building ground is frequently omitted. For the satellite systems, the NEC/CEC require bonding of the antenna mounting hardware, as well as the incoming cable sheath, to the building ground. This is often difficult to do. If the incoming CATV or antenna lines can be routed to a distribution closet near the AC service entry point, the required bonding can be achieved.
Oh, “lightning protection”… Well, that’s a different story… Here’s the lightning protection for my receiver site building. (slideshow)
http://k5ted.net/slide_show.html?picture=picture1.jpg&show=Earthing
200’ 750MCM bare copper in a 4’ trench on a bed of electrolytic barite, then covered with same, and three 4’ x 8’ L shaped chemical electrodes, CAD bonded to the runner.
The rooftop antenna mast is metal, attached to metal unistrut, attached to a building steel ceiling beam, and the antenna feedline terminates to a gas discharge surge arrestor (grounded to building steel) right before the FA filter.
And there is the lightning rod… Yep. The tall mast looking thing…
Except for that it isn’t really a lightning rod, per se. It is an ionizer. Basically creates an “umbrella” of sorts over the building.
To be clear about this - that protector will not do anything unless it is located to make a low impedance (ie less than 10 foot) connection to earth. No protector does protection. That protector is effective because it has a terminal to make a low impedance (ie hardwire has no sharp bends) connection to single point earth ground.
Antenna lead must go down the outside of a building to make that low impedance connected (via protector). Only then enter a building. If that wire enters before making a connection to single point earth ground, then a surge is inside a structure and hunting destructively for electronics.
Protection was always about connecting that transient to earth BEFORE it can enter a structure.
I have a similar setup for my house but I used 751MCM for a little extra protection. You might say its overkill but I read on the internet that sometimes 750MCM just cant cut it. I found these plans on the internet that I modified for my use. I stripped the core conductor out of some RG-6 quad shield and wrapped it around the 750MCM at one turn per 67mm. I buried it at 53.25 inches to compensate for the resistance of the soil in my yard. Pfff, who else has a ground wire system tuned to 1090? :mrgreen: