[Elecraft] Disconnecting, grounding, lightning, etc..

[Jay Schwisow]

Here is an eham posting from a friend and RF engineer with Sprint - Mike 
Higgins K6AER. Mike has helped me with my station and taught classes to 
many. There is lots more to protecting your house, family and belongings 
than just disconnecting coax...read on.

 From Mike Higgins on Eham 3/2006:

Well it is that time of the year when postings turn to grounding and 
lighting protection.

So much information has been posted on lightning protection in this 
fourm you could spend hours going through all the information listed and 
I would recommend doing so. Use the search engine in eHam and by all 
means forget the naysayers of grounding. Go to the PolyPhaser site and 
read their tutorials on lightning protection. Go to Lyncole, Hagar and 
ICE (Industrial Communications Engineers) and read their tutorials on 
grounding. There is no short cut to lighting protection. Your whole 
station and home needs to be addressed as a complete solution. 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 
article is a reader's digest version of what must be done for surge 
protection and I hope it start you thinking about your home and station.

Every other year on average my station gets hit by lightning. This was 
not a problem when I lived in LA; I had a greater chance of being hit by 
stray bullets. I live in a very high lightning prone area called the 
Palmer divide in Colorado. June through August we have thunder storms 
every day with up to 40,000 strikes a day on average during those 
months. I am on my 3rd GP-9 antenna at the top of the tower. When a 
storm has gone by and I find what's left of a GP-9 in toasted shards all 
over the ranch, it doesn't take a rocket scientist to know what 
happened. I have lost no base station equipment to a lightning strikes 
but I have spent considerable time putting in proper grounding and surge 
protection on my station. As for the tower top fiberglass omni sticks, 
they're sacrificial and that just the cost of doing business where I live.

Proper grounding and surge protection works and works very well. The key 
is setting up low resistance grounding and the proper installation of 
grounding material. Disconnecting you equipment and putting it into a 
Faraday Shield box 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 my 
self have more than one radio and going this route would mean my hobby 
is station assembly. I can't speak for most hams but after doing that a 
few times it looses its novelty.

The cell phone industry looses less then 20 sites a year to lightning. 
There are approximately 500,000 sites between Verizon, Nextel, Cingular, 
Sprint and others. Generally it is because the DSL line is struck and 
not the radio equipment. In the cell phone industry we ground at the top 
of the tower, 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.

Power lines take by far the greatest hits and the pole flash-over-rods 
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 protectors connected to the panel. You 
worry about your ham equipment but what about your expensive 
entertainment and appliances not to mention the possibility of fire. You 
can protect your home and panel for under $100. Intermatic makes the 
Panel Gard model number IG1240RC surge protector for $60 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 three 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 your 
live in a highly lightning prone areas like Colorado, Florida and much 
of the mid west, lighting rods are a good investment. National Lightning 
Protection 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 is bonded with a number “0” solid 
copper bonding wire. My ground resistance is less than 3 ohms. I have 
several deep (20ft. by 2 inch) ground rods for the tower, AC panel and 
shack location. I also have a surface ground field of 21 8ft. ground 
rods spaced 16 feet apart, spread out in radials from the tower. At the 
base of the tower is a lightning/surge protection panel for the coax, 
rotor cables and stepper motors on the beam. For the surge protection 
box I use 2 inch wide copper strap. Copper strap has much lower 
impedance than copper wire and much of lightning's energy is in the RF 
spectrum.

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 3000 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 this is 
excessive but proof is in the pudding. I have suffered no equipment 
losses due to lightning strikes.

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 communication 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 you 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 would it not be easier 
to prevent the damage in the first place. Due the proper diligence and 
you'll sleep better at night.