Hi all,
For years I lived in an apartment and just had antenna's in the attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of serious
thunderstorms, and the accompanying lightning, I'm a bit concerned about
properly grouding the antenna so that I don't fry the house *smile*. I
know about some articles on the ARRL site, but was wondering if anyone
else had some ideas or pointers on how to practically do this ?

Jerry

"Jerseyj" wrote in message
...
Hi all,
For years I lived in an apartment and just had antenna's in the
attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of
serious
thunderstorms, and the accompanying lightning, I'm a bit concerned
about
properly grouding the antenna so that I don't fry the house *smile*.
I
know about some articles on the ARRL site, but was wondering if
anyone
else had some ideas or pointers on how to practically do this ?

Jerry

Have a look at www.furse.com

They used to do a very good pamphlet about lightning and protection.


--
Woody

harrogate2 at ntlworld dot com

In article ,
Jerseyj wrote:

For years I lived in an apartment and just had antenna's in the attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of serious
thunderstorms, and the accompanying lightning, I'm a bit concerned about
properly grouding the antenna so that I don't fry the house *smile*.

That's a very good concern to have!

I'd encourage you to consult with a local professional (electrician)
who is familar with your local conditions (weather, soil, electrical,
and legal).

I
know about some articles on the ARRL site, but was wondering if anyone
else had some ideas or pointers on how to practically do this ?

You might find it useful to review the following document:

http://www.radagast.org/~dplatt/hamr...-grounding.pdf

It's probably got more information than you want or need, but some
sections of it could be quite useful in planning your system.

Understanding the requirements of your local electrical code (which is
probably based in large part on the National Electric Code) would also
be a good idea. The text of the NEC isn't available online as far as
I know (it's copyrighted) but I understand that most good libraries
should have a copy.

The basic approach you'd want to take, I believe, is to make sure that
the feedline is well grounded immediately before it enters your
building. You'll probably want to hammer in a new ground rod at this
location, in order to keep the distance between grounding point and
ground to a minimum, and if you do so you should/must install a
heavy-gauge "bonding" wire between this ground rod and your building's
main grounding point (probably at the electrical service entrance).

Installing lightning/surge suppressors of one sort or another in the
feedline at the grounding point would also be a good idea. They might
help shunt away a high-voltage spike, induced by a nearby lighting
strike, which could damage your equipment.

If your shack is not on the first floor, it'd probably be a good idea
for you to run the feedline down the wall to ground level, ground it
there, and then run it to the antenna.

You might want to consider an arrangement in which the antenna
feedline drops down from the feedpoint to ground level, is connected
to a ground rod at that point, and then runs along or through the
ground to your house (use a "direct bury" coax, in this case, to avoid
contamination of the cable by soil moisture and chemicals!). This
could help keep direct- or near-direct-strike current away from your
house.

One of the best things you can do is to have some sort of easy-access
connector coupling, located outside the house (e.g. at the grounding
block). If a storm seems imminent, or any time you won't be using the
rig for a while, disconnect the end of the antenna feedline and toss
it away from the house.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Hi Jerry,

Dave's comments are accurate and helpful, in almost every case.
But there is the possibility of a very substantial simplification here.

The Key Question: Do you need or want to operate your rig during
electrical storms?

If the answer is YES, then you better do everything Dave suggests--
and possibly a whole lot more. Praying a little might also be helpful.

But if the answer is NO, then you would probably do just fine
(with respect to antenna-specific risk) using the last suggestion only:

One of the best things you can do is to have some sort of easy-access
connector coupling, located outside the house (e.g. at the grounding
block). If a storm seems imminent, or any time you won't be using the
rig for a while, disconnect the end of the antenna feedline and toss
it away from the house.

The main thing to remember on this one is that the more CONVENIENT
you make your disconnect, the more likely it will be that you'll actually
USE it appropriately.

73, Ed, W6LOL

For a receiving antenna, a coherer provides excellent lightning
protection.

Unfortuantly, on a transmitting antenna, the rf would immediately make
the coherer conductive and a direct short to ground (perhaps very low
QRP power could be used?)

One can easily be construted with a bottle filled with metal filings,
two bare wires are inserted into the filings (not touching and
seperated by a substantial amount of the filings), one wire goes to a
good earth ground, the other to the antenna.

If the coherer shorts to ground it only needs to be shaken to reset (I
would suspect in a real lightning strike the metal would be fused,
quite possibly even vaporized.)

John

"Jerseyj" wrote in message
...
Hi all,
For years I lived in an apartment and just had antenna's in the
attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of
serious
thunderstorms, and the accompanying lightning, I'm a bit concerned
about
properly grouding the antenna so that I don't fry the house *smile*.
I
know about some articles on the ARRL site, but was wondering if
anyone
else had some ideas or pointers on how to practically do this ?

Jerry

On Sun, 17 Jul 2005 08:07:15 -0400, Jerseyj
wrote:

Hi all,
For years I lived in an apartment and just had antenna's in the attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees.

I have a 10-80 wire connected between 3 trees. It's fed with
ladderline. Lightning protection is simple -- with banana plugs and
jacks, I can unplug the ladderline just outside the window whenever it
looks rainy.

You might think about whether you want to use coax or some kind of
balanced line -- balanced line is a simple disconnect.

bob
k5qwg

Given the recent spate of serious
thunderstorms, and the accompanying lightning, I'm a bit concerned about
properly grouding the antenna so that I don't fry the house *smile*. I
know about some articles on the ARRL site, but was wondering if anyone
else had some ideas or pointers on how to practically do this ?

Jerry

"Jerseyj" wrote in message
...
Hi all,
For years I lived in an apartment and just had antenna's in the attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of serious
thunderstorms, and the accompanying lightning, I'm a bit concerned about
properly grouding the antenna so that I don't fry the house *smile*. I
know about some articles on the ARRL site, but was wondering if anyone
else had some ideas or pointers on how to practically do this ?

HI,

Good to read : http://www.astrosurf.org/lombry/qsl-...protection.htm

Personnaly, in my humble opinion, under thundery weather there is no better
solution than unpluging all electronic devices...

Thierry, ON4SKY


Jerry

Jerry wrote:
"I know about some articles on the ARRL site, but was wondering if
anyone else had some ideas or pointers on how to pratically do this?"

Coax helps protect your radio from lightning. It rejects common-mode
currents inside which might otherwise damage the radio.

Thunderstorms often produce lightning from clouds charged to 100 million
volts with respect to the earth. Current may oscilate up to 200 thousand
amps in a lightning discharge. Temperature inside the stroke may reach
30 thousand degrees C (5x the temperature of the sun`s surface).

A stroke starts and stops abruptly, so it contains r-f in addition to
d-c. The discharge may take up to 150 milliseconds and consist of
several flashes in both directions. It may include a path
miles long, so it has a pretty good ionization trail for an antenna.

If your antenna is struck by lightning, it is best to bypass the energy
aroundb people and equipment.

Medium wave stations have arc-gaps around the tower base insulators,
Faraday screens between primary and secondary of tower r-f coupling
transformers, and tower lighting chokes which keep both r-f and
lightning out of the power mains.

High frequency stations often use balanced wire lines, and these have an
arc-gap from each wire to the earth at a point outside the station.

VHF, UHF, and microwave stations use grounded antennas and coax. Towers
which support the antenna generally have each tower leg separately
grounded by a heavy cable to its own ground rod near the tower base. R-F
cables and waveguide are grounded at the antenna and at least at the
base of the tower. Coax nay be coiled with several turns between the
tower base and the shack to discourage lightning on the outside of the
coax from entry to the shack. Waveguide is solidly bonded to the tower
but not usually coiled to make a lightning choke.

The solid-state VHF, UHF, or microwave station often needs additional
surge protection because of the difference in potential between electric
service and antenna system grounds
This takes the form of husky r-f chokes in each power wire to the r-f
equipment. Each choke is shunted at each end to ground with a capacitor
and with a voltage limiting device or devices, often MOV`s. There are
ready-made brute force coil and capacitor low-pass pi-filters which need
only addition of MOV`s to make them effective lightning suppressors. I
made mine in an earlier time using Miller Coil Company tower lighting
chokes and they worked well. You could wind 2 or 3 dozen turns of #12 or
#14 insulated wire in an 8-in. dia. circle to make your own 0.1
millihenry chokes. The standard choke used to be 2.5 millihenry, but it
is not critical.

The same wiring techniques required for noise reduction apply to the
biggest noise of all, lightning.

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...
Jerry wrote:
"I know about some articles on the ARRL site, but was wondering if
anyone else had some ideas or pointers on how to pratically do
this?"

Coax helps protect your radio from lightning. It rejects common-mode
currents inside which might otherwise damage the radio.

Thunderstorms often produce lightning from clouds charged to 100
million
volts with respect to the earth. Current may oscilate up to 200
thousand
amps in a lightning discharge. Temperature inside the stroke may
reach
30 thousand degrees C (5x the temperature of the sun`s surface).

A stroke starts and stops abruptly, so it contains r-f in addition
to
d-c. The discharge may take up to 150 milliseconds and consist of
several flashes in both directions. It may include a path
miles long, so it has a pretty good ionization trail for an
antenna.

If your antenna is struck by lightning, it is best to bypass the
energy
aroundb people and equipment.

Medium wave stations have arc-gaps around the tower base insulators,
Faraday screens between primary and secondary of tower r-f coupling
transformers, and tower lighting chokes which keep both r-f and
lightning out of the power mains.

High frequency stations often use balanced wire lines, and these
have an
arc-gap from each wire to the earth at a point outside the station.

VHF, UHF, and microwave stations use grounded antennas and coax.
Towers
which support the antenna generally have each tower leg separately
grounded by a heavy cable to its own ground rod near the tower base.
R-F
cables and waveguide are grounded at the antenna and at least at the
base of the tower. Coax nay be coiled with several turns between the
tower base and the shack to discourage lightning on the outside of
the
coax from entry to the shack. Waveguide is solidly bonded to the
tower
but not usually coiled to make a lightning choke.

The solid-state VHF, UHF, or microwave station often needs
additional
surge protection because of the difference in potential between
electric
service and antenna system grounds
This takes the form of husky r-f chokes in each power wire to the
r-f
equipment. Each choke is shunted at each end to ground with a
capacitor
and with a voltage limiting device or devices, often MOV`s. There
are
ready-made brute force coil and capacitor low-pass pi-filters which
need
only addition of MOV`s to make them effective lightning suppressors.
I
made mine in an earlier time using Miller Coil Company tower
lighting
chokes and they worked well. You could wind 2 or 3 dozen turns of
#12 or
#14 insulated wire in an 8-in. dia. circle to make your own 0.1
millihenry chokes. The standard choke used to be 2.5 millihenry, but
it
is not critical.

The same wiring techniques required for noise reduction apply to the
biggest noise of all, lightning.

Best regards, Richard Harrison, KB5WZI


An interesting fact that many don't know is that lightning actually
strkes upwards as the clouds are negatively charged.


--
Woody

harrogate2 at ntlworld dot com

Thierry wrote:

SNIPPED

HI,

Good to read : http://www.astrosurf.org/lombry/qsl-...protection.htm

Personnaly, in my humble opinion, under thundery weather there is no better
solution than unpluging all electronic devices...

Thierry, ON4SKY

Agree! But, I still lost an ICOM 756 Pro II when disconnected from
antenna,
and had the power supply unplugged. A ground loop in the external ground on
the 756 and the power supply, where 12 volt return is tied to chassis,
caused
damage to the power connector on the 756 and fried the 756 internal
cabling and
circuit boards were carbonized.

I'm still waiting for my insurance settlement.

MORAL: Lightning does what lightning does!