| |
Antenna ---------+--------| |----------- To Radio
| | |
SPARK V Blocking
GAP ^ Capacitor
|
Ground ---------+----------------------

PS: The breakdown voltage of the capacitor should be
10 times that of the spark gap. For a 1KV spark gap,
that would give 10 KV.

JEB

K7JEB wrote:

| |
Antenna ---------+--------| |----------- To Radio
| | |
SPARK V Blocking
GAP ^ Capacitor
|
Ground ---------+----------------------

PS: The breakdown voltage of the capacitor should be
10 times that of the spark gap. For a 1KV spark gap,
that would give 10 KV.

JEB

2uF at 10kV, quite a capacitor. That would be 6 ohms or so on
topband. As I understand it, there is nothing that can work if
a direct lightening strike occurs. We are talking megavolts and
thousands of amps. Way beyond anything an amateur could build.
The best we can hope for is to dissipate charge build up on the
aerial and ensure that there is no more than a kilovolt or so at
the input to the rig caused by the (field) effects of a nearby
strike. A spark gap that can conduct a lightening strike would
be the size of a small truck.

The only way to make sure you have a working station after a
lightening strike on your aerials is to take out good insurance.

vy 73

Andy, M1EBV

Effective lightning protection can be done in the amatuer station for a
reasonable cost. Most though, don't do so.
"Andy Cowley" wrote in message
...

As I understand it, there is nothing that can work if
a direct lightening strike occurs.

CW wrote:
Effective lightning protection can be done in the amatuer station for a
reasonable cost. Most though, don't do so.

My costs have always been reasonable - I unplug the antenna
when not in use. I don't use it during thunderstorms. I have
lived in extreme lightning areas with zero problems.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:

CW wrote:
Effective lightning protection can be done in the amatuer station for a
reasonable cost. Most though, don't do so.

My costs have always been reasonable - I unplug the antenna
when not in use. I don't use it during thunderstorms. I have
lived in extreme lightning areas with zero problems.


All good stuff, Cecil, but I'd say that was lightening avoidance
not protection. I still don't believe there is an effective method
of lightening protection for an amateur station that will accept a
direct strike and survive. Even your method would probably result
in a fried antenna ;-) Hope you never find out!

vy 73

Andy, M1EBV

Andy Cowley wrote:
All good stuff, Cecil, but I'd say that was lightening avoidance
not protection. I still don't believe there is an effective method
of lightening protection for an amateur station that will accept a
direct strike and survive. Even your method would probably result
in a fried antenna ;-) Hope you never find out!

I've been back in Texas for about 5 years now and the only thing
that has gotten fried was a five-foot-tall live oak tree, the
shortest thing around. Go figure. It's still struggling to stay
alive with half its branches dead and a burn mark down the trunk.
--
73, Cecil http://www.qsl.net/w5dxp



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On Mon, 15 Dec 2003 13:51:49 -0600, Cecil Moore
wrote:

Andy Cowley wrote:
All good stuff, Cecil, but I'd say that was lightening avoidance
not protection. I still don't believe there is an effective method
of lightening protection for an amateur station that will accept a
direct strike and survive. Even your method would probably result
in a fried antenna ;-) Hope you never find out!

I've been back in Texas for about 5 years now and the only thing
that has gotten fried was a five-foot-tall live oak tree, the
shortest thing around. Go figure. It's still struggling to stay
alive with half its branches dead and a burn mark down the trunk.

My system gets hit about 3 times a year. So far I've only lost the
front end out of a 2-meter rig and some coax. Since installing the
new tower I've not lost any radio gear, but I did get one computer
fried.

http://www.rogerhalstead.com/ham_files/tower.htm
shows the tower and antennas, but not the ground system.

There are currently 30, 8' ground rods and over 600 feet of bare #2
copper tying the whole works together.

Unfortunately we had to have some septic work done. When digging out
the tank they hooked the ground system. Pulled out a section of the
basement wall and cracked a whole bunch of it. The wall is
temporarily repaired, but we are going to have to replace the entire
wall this coming season.


IF you have a fast connection the view from the top of the tower
http://www.rogerhalstead.com/ham_files/tower.htm panorama.
It's over 19 megs and would take forever on dial up.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com
Return address modified due to dumb virus checkers

Andy Cowley wrote in message I still don't believe there is an effective method
of lightening protection for an amateur station that will accept a
direct strike and survive.

There is, but most hams don't do it. Costs money, and everything has
to be set up just right. It's done the same way all other 24 hour
radio/tv stations, etc do it. How many commercial radio stations have
you heard that go off the air when lightning strikes their tower? Not
many I bet. We would never have reliable broadcast TV in this town if
that were the case.. :/ MK

CW wrote:

Effective lightning protection can be done in the amatuer station for a
reasonable cost. Most though, don't do so.
"Andy Cowley" wrote in message
...

As I understand it, there is nothing that can work if
a direct lightening strike occurs.

How? How do you deal with thousands of amps? It's for certain sure that
a simple spark gap will be blown to kingdom come in the first millisecond,
so what happens in the next millisecond? and the one after...........

I think your method must be untried, untested and 'whistling in the dark'.

Andy, M1EBV

If it weren't possible, millions of dollars of radio equipment would go up
in smoke every year. There are places that, if you have a tower, you WILL
get hit on a regular basis. If you would like to know something about it, do
a search on this group for Gary Coughman. Also, take a look at the
Polyphaser web site. Before you start accusing someone of not knowing what
they are talking about, you would be well advised to ensure that it is not
you that is ignorant.


"Andy Cowley" wrote in message
...
CW wrote:

Effective lightning protection can be done in the amatuer station for a
reasonable cost. Most though, don't do so.
"Andy Cowley" wrote in message
...

As I understand it, there is nothing that can work if
a direct lightening strike occurs.

How? How do you deal with thousands of amps? It's for certain sure that
a simple spark gap will be blown to kingdom come in the first millisecond,
so what happens in the next millisecond? and the one after...........

I think your method must be untried, untested and 'whistling in the dark'.

Andy, M1EBV