Mike may be a stranger to our Newsletter, but he's no stranger to Alpha Amplifiers.  He's been doing much of the work on the new 6 Meter Amplifier - the Alpha 8406, and he was also our chief beta tester for the Alpha 8410.  We got him to put down his soldering iron and pick up a pencil.  This month he's writing an article about Lightning Protection. 

The first installment of a three part article:

There comes a time in station assembly when simply tossing the coax out the window is no longer is a viable solution to lightning protection.

No piece of equipment, including a beefy amplifier, is immune to damage from a lightning surge.

So much information has been posted on lightning protection that you could spend hours going through it all. Unfortunately much of the general information listed in Ham Web Blogs is based on myth and conjecture, rather than on science. To find suitable protection equipment, you need to do more extensive research from the manufacturer's of lightning surge equipment.

Now if you live in the Northwest you can skip the rest of this article for your chances are very slim you would even see a thunderstorm. For the rest of the county, this is an aspect of the hobby we have to deal with. This tutorial is a reader's digest version of what must be done for surge protection and I hope it will start you thinking about your home and station and what needs to be done.

Tutorials on lightning protection can be found on the PolyPhaser site  http://www.protectiongroup.com/PolyPhaser . Go to Lyncole http://www.lyncole.com/ , Hargar  http://www.harger.com/  and ICE (Industrial Communications Engineers) http://www.iceradioproducts.com/ and read their tutorials on grounding.

There is no short cut to lighting protection. Your whole station and home need to be addressed as a complete solution. Remember lightning doesn't always come into your station via the antenna. Look at the possible entry points from a lightning point of view in lightning connecting to the earth. AC, phone, cable TV as well as HAM coax and control lines from the antenna to earth are in play.

Proper grounding and surge protection work and work very well. The key is setting up low resistance grounding, understanding the impedance path to earth and the proper installation of grounding material. Disconnecting you equipment and putting it into a Faraday Cage will work well but if you live in an area like my QTH you would be off the air for 3-4 months every year. Some hams, like myself, have many radios and going this route would mean my hobby is station assembly, rather than station operating, hi, hi. I can't speak for most hams but such complete disassembly and reconstruction soon loses its novelty.

The cell phone industry loses fewer then 50 sites a year to lightning. There are approximately 500,000 sites between Verizon, Nextel, AT&T, Sprint and others. Generally it is because the DSL line is struck and not the antenna/radio equipment. In the cell phone industry we ground at the top of the tower (antennas), base of the tower and where the cable goes into the facility. The facility has a ground halo inside and the all equipment is grounded to NEC code. Surge protectors are connected for all incoming and outgoing lines at the ground demarcation point. Site ground resistance is generally below 3 ohms. Four 20 foot deep ground rods is a grounding minimum. The AC entry panel has surge protectors (95% of all lightning damage comes in through the AC panel) and most importantly all the facility grounding is bonded together to a common demarcation grounding point.

Power lines take by far the greatest hits but the pole flash-over-rods will pass any surges below 10,000 volts. That still leaves a lot voltage coming down the power line. The primary and secondary portion of the pole transformer can arc over and your home is next in line. Your home AC panel should have a surge protector connected to the panel. You worry about your ham equipment but what about the rest of your expensive entertainment equipment and your appliances, not to mention the possibility of fire. You can protect your home and panel for under $100 from AC surges. Intermatic makes the Panel Gard model number IG1240RC surge protector for $70 not including the two additional circuit breakers. This unit has LED's to indicate the units status and wither you have taken a power surge. Installation is just four wires into the panel.

Did I mention lightning rods for the roof? Lightning is fickle and might miss your gorgeous tower and strike through the roof to the electrical wiring in the ceiling. The ground return in your home wiring connects to the master ground in your AC panel. Remember a lighting discharge is looking for the lowest impedance path to ground, i.e. earth. If you live in high lightning prone areas like Colorado, Florida and much of the midwest, lighting rods are a good investment. National Lightning Protection http://www.theprotectionsource.com/ in Denver makes all the necessary material to install your lightning rod system. Their web site is a wealth of information.

In my own station, all grounding points are bonded with a number "4" solid copper bonding wire. My ground resistance measured at the ground rods is less than 3 ohms. I have several deep (20 ft. by 2 inch) ground rods for the tower, AC panel and shack location. At the base of the tower is a lightning/surge protection panel for the coax, rotor cables and stepper motors on the beam. Inside the surge protection box, I use 2 inch wide copper strap for ground connections. Copper strap has much lower impedance than copper wire for much of lightning's energy is in the RF spectrum and the skin effect comes into play. Flat strap has a much larger area than round wire.

My coaxes are grounded at the top of the tower as well as the base. The AC panel has a commercial lightning protection panel to take care of incoming AC surges. The whole station is run on a pair of 5000 watt APC UPS systems to isolate the AC main from the equipment for minor surges. At the station, coaxes are terminated at a pair of grounded Alpha Delta coax switches and during storms the coax switches are in the grounded COM position. All equipment is grounded to a master ground buss bar on the back of the operating station. The master AC feed to the station has a commercial disconnect in the shack. I know many of you will think this is excessive but the proof is in the pudding. I have suffered no equipment losses due to lightning strikes and I have had quite a few.

Let's look at a typical lightning strike from two perspectives. If the strike is on the tower the voltage is to earth is like a resistance divider. Your equipment is somewhere between the cloud voltage and earth ground. Using surge protection equipment is only part of the voltage mitigation strategy. If you earth connection is poor the voltage will travel through the home wiring looking for a better ground to earth. This is why all grounds must be tied together and your ground resistance must be a low as possible. Unless you live in a salt water swamp a single 8 foot ground rod will not be enough. The lower the ground resistance via the ground system the lower the voltage the surge protectors have to dissipate at the base of the tower or cable entry point.

Remember if the cell phone, radio, public service and computer industry disconnected equipment for every summer storm, you would not have communications coverage or internet service for five months every year. The communications industry is connected 24/7. As a result, proper lightning/surge protection with good grounding works. Is it 100 % full proof...NO, but it is infinitely more effective than sticking your head in the sand with denial. You don't plan on getting into an accident but you have car insurance. Lightning surge protection is an insurance policy and another tool in your station/home safety plan.

Many hams have their station and personal electronics insured but collecting and replacing equipment is tedious and it would be easier to prevent the damage in the first place. Do the proper diligence and you'll sleep better at night.

In the second series we will discuss the AC panel surge protectors, ground rods, sphere of influence of ground systems, grounding in poor soil and grounding material.

73, Mike - K6AER