16

There's a lot that can be said about lightning protection, but it usually boils down to doing all of these things: make good, low impedance connections to Earth bond all Earth connections together with a low impedance path have only a single point of entry to protected equipment A real problem when discussing lightning protection is that people will ...


6

That statement is wrong on several levels. The antenna is DC grounded so no lighting arrestor is needed. A lightning arrester is needed, even if the antenna is DC ground. The arrester's job is to limit the center conductor's voltage to be not very different from the shield. That the antenna is "DC grounded" isn't worth much. Lightning is not DC. In fact,...


6

QST magazine printed a comprehensive three part article in 2002 addressing lighting: Lightning Protection for the Amateur Radio Station. They are republished by the ARRL. QST June 2002, pp. 56-59 QST July 2002, pp. 48-52 QST August 2002, pp. 53-55 The surest way to protect your radio gear is to disconnect it from power, from the antenna, from your computer ...


6

what would be the theoretical disadvantages of such a disconnect system? Firstly, keep in mind that antennas don't cause lightning damage: grounds do. It's not clear from your description if your patch panel is grounded at the same point as your electrical service or not. If it's not, you have two separate grounds. This doesn't comply with the NEC, and it ...


6

They are not intending to keep operating in spite of a thunderstorm in the vicinity, are they? That would be very dangerous and foolish. Well in advance of the storm, the group must unplug the equipment, antennas, and power and get into a suitable building or vehicles until the storm is well past. There may be some good information in this search.


6

The picture you have drawn suggests a lightning suppressor installed in this way will do little to nothing to protect your station. The suppressor does only one thing: it limits the maximum voltage between the center conductor and the shield. It doesn't do anything to limit strike current on the shield, which is where most of the energy is anyhow. The ...


5

I'd recommend one of two solutions: 1. Don't throw it out the window. Most lightning damage comes not from direct strikes but nearby strikes, which can still induce large-ish voltages on the feedline: not enough to make lightning, but enough to damage things. A couple feet of air between the feedline and the tranciever will protect against this. If you do ...


5

Many companies make lightning surge protectors. the install in the coax to your radio and divert the strike to ground. NOTE: THERE IS NO SURE WAY TO PROTECT YOUR RADIO EXCEPT DISCONNECTING IT FROM POWER AND THE ANTENNA. Search for polyphaser, they are well respected, MFJ also makes some lower cost options..


4

The Polyphaser consists of a DC blocking capacitor in series with the radio and a gas discharge element in parallel with the antenna. The Polyphaser can normally withstand multiple <20 kA strikes without failing. Unfortunately, in the far majority of the cases, the gas discharge element fails in an open state. There is therefore no practical, absolute ...


4

Seems mythical. For example, this article discusses in a fair amount of detail why this doesn't work for sailboats. Land-based antennas face the same issues. Some people believe that by constantly discharging the charge build-up on an object, the magnitude of the charge imbalance can be controlled and kept to a level where a lightning strike will not ...


4

The E and H fields of all RF signals travel at exactly the same speed - the speed of light. The phase relationship between the two fields remains constant as they travel through various mediums. Lightning in itself is not an RF signal but it does emit RF (with E&H waves) as it propagates. [EDIT] After reading some of the additional dialog provided by ...


4

You should definitely ground the antenna to your earth system with a heavy conductor. The coax alone will not cope well with the lightning current. By carrying a share of the current, the earth wire also reduce the voltage transferred to the coaxial cable inner conductor, and hence the load on the lightning protection device. Better would be a metal cable ...


4

These ideas have been around for centuries as lightning dissipation theory and lightning diversion theory. Notably, Benjamin Franklin was an early proponent of lightning dissipation theory. He noticed on a small scale that a static charge could be dissipated without a spark by bringing a grounded needle near a charged object. He correctly reasoned lightning ...


4

Your two ground conductors must be connected at both ends. They must be connected at the bottom because that's where the ground is and they aren't ground conductors if they aren't connected there. And they must be connected at the top because if they are not, you don't have a single point ground. Without a single point ground the potentials between the two ...


3

I suspect this scheme will do little or nothing to decrease the chance of damage to your equipment in the case of a lighting strike. For the sake of argument, let's just presume that it does work as you expect: lighting always strikes the rod, which has a dedicated conductor to a dedicated ground rod, and all of that is sufficiently isolated from everything ...


3

One enthusiast reports, ".029" spacing for a KW station, and .045" spacing for 2.5 KWs" Keep in mind that a lightning arrestor doesn't stop an electrical discharge event, it merely shunts most of the energy to ground. There's still a lot of damaging current that ends up in the wire which will damage attached equipment. See How can I protect equipment ...


3

What you need to do is follow the requirements of the National Electrical Code (assuming USA). This article covers it well. (ps. Failure to comply with NEC 810 is the #1 reason ham radio operators in the US have fire insurance claims denied, and why they have to buy ARRL's silly little insurance policy. If you follow NEC 810 and get permits for your work, ...


3

A discharge tube would serve to protect your rig from a close strike. Apart from that, make sure you have a decent ground for your shack. Having said that, it's probably not a good idea to operate in heavy weather. Unless absolutely necessary to continue operation, I'd go QRT, and disconnect the coax from the rig.


3

There's no easy way to weatherproof it, but only you can know how bad the weather is likely to get, and balance the effort and cost of providing protection against the actual needed protection. If you do want to throw it outside and protect it, though, one method that works fairly well is to take a piece of capped PVC mounted so the cap is up, forming a ...


3

What is "proper" grounding and protection? In my experience, most amateur stations that have installed grounding and surge protection devices have not installed them properly. Surge protection devices are designed to handle relatively small voltage transients, not handle surge currents on the order of a lightning strike. And with the tremendous currents ...


3

The dimensions of a typical "knife switch" make it well suited to the high impedance of the open-wire or "ladder" transmission lines which were ubiquitous "Long ago." While the wide spacing between the switch's "protected" and "operating" positions provides a significant level of lightning protection, it would also present a substantial impedance ...


3

Protecting equipment and property with an antenna such as this is no different than with any other antenna. See How can I protect equipment against a lightning strike?


2

Get a two terminal GDT and call it a day, use very short low inductance leads to attach it between the center conductor and earth ground. GDT (Gas Discharge Tube), Bourns make them, Digikey or Mouser may have them. GDTs are high-impedance, very fast-acting, very high-energy devices for surge protection. MOV (Metal Oxide Varistor) devices may have low enough ...


2

These alternative air termination systems are a triumph of marketing over physics. I'll quote what I can easily find on the net, you will find a lot more with a bit of digging. These statements are quite reserved, but the meaning is clear - there is no evidence that there is any system that works to dissipate, preferentially attract or repel lightning. The ...


2

You question seems to boil down to this: "Do I need to be concerned about lightning protection, even though my antenna isn't very high relative to its surroundings?" The answer is yes. In fact you need to worry about lighting protection even if you have no antenna at all. Say you have this: simulate this circuit – Schematic created using CircuitLab ...


2

The typical amateur radio / SWL budget will rarely allow for sufficient protection from a direct lightning strike. More often than not, the measures taken help minimize damage from a direct strike but more importantly they mitigate damage from near lightning strikes and static build-up. If the goal is to bleed static and minimize damage then mast should be ...


2

The W8JI information is pretty good, there are a few points he doesn't touch on though. "EARTHING" or Grounding is a hot subject in many areas and there are many theories related to it. The NEC and NFPA recommend that ALL "Extra" grounds attach back to the electrical service ground ( I suggest you read up on this). Arizona presents its ...


2

Polyphaser sent me a document on request. Salient points: The only way to test the IS-50 or IS-B50 without expensive test equipment is by seeing if the VSWR (return loss) has increased or remove it from the line and see if the radio performance is better. Because the product is a DC block device, there is no way to test adequately with a multi-meter. ...


2

FORGET the third horizontal (yellow) loop antenna! I finally disabled mine because it caused me no end of trouble with noise pickup and thousands of spurious signals sent to the BT (Blitzortung) servers in Europe. Although it appears in the official documentation, I have not been able to find anyone who is using one. Most are using just two vertically-...


2

The lightning detection antennas are not used in any sense to triangulate or to direction find through any other method such as phasing. The three antennas are there simply to provide quasi 360° detection of lightning events. The actual direction finding is accomplished by analyzing the timing of detected lightning events from multiple sites using GPS time ...


Only top voted, non community-wiki answers of a minimum length are eligible