I have a Cushcraft A3S Beam on a tower. It does not currently have a
lightning arrestor on the feed line and is working well. The feed
arrangement is center conductor to one side of the driven element,
shield to the other side. There is a coil of coax at the top as a
choke. This leaves the elements and the coax ungrounded. I have relied
entirely on disconnecting the antenna for protection. when not in use.
I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.

Comments & opinions please...
de W8CCW John
John Ferrell W8CCW

Two options:
#1 Unplug when not in use
#2 Throw it out the window after it's unplugged!!

Guiding logic: Lightning is better outside the shack than inside the
shack. :-)

John Ferrell wrote:

I have a Cushcraft A3S Beam on a tower. It does not currently have a
lightning arrestor on the feed line and is working well. The feed
arrangement is center conductor to one side of the driven element,
shield to the other side. There is a coil of coax at the top as a
choke. This leaves the elements and the coax ungrounded. I have relied
entirely on disconnecting the antenna for protection. when not in use.
I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.

Comments & opinions please...
de W8CCW John
John Ferrell W8CCW

I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.

Once you have more than one or two antennas, disconnecting the feedlines
and throwing them out the window gets to be a real pain.

you probably want to

a) ground the shield of the coax at the base of the tower, and
b) have a lightning arrestor where the coax enters the house or at
your shack, and
c) connect the grounds of the tower, shack, and power co. together

I ground the coax shields at the base of my towers, run the coax
underground to the house, and then have lightning arrestors at the
house before the coax goes up to the shack on the 2nd story.

Tor
N4OGW

On 27 Apr 2006 17:24:55 -0500, wrote:

I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.

Once you have more than one or two antennas, disconnecting the feedlines
and throwing them out the window gets to be a real pain.

you probably want to

a) ground the shield of the coax at the base of the tower, and
b) have a lightning arrestor where the coax enters the house or at
your shack, and
c) connect the grounds of the tower, shack, and power co. together

I ground the coax shields at the base of my towers, run the coax
underground to the house, and then have lightning arrestors at the
house before the coax goes up to the shack on the 2nd story.

Tor
N4OGW

Don't forget the control wires for your antenna rotator. Seems like
all your antennas and control cable(s) entering the shack through
arrestors on grounded metal plate is the recommended method these
days.

You can find some good poop on lightning protection he

http://www.iceradioproducts.com/thorshammer.htm

http://www.iceradioproducts.com/10.html


S.T.W.

The low response to the question leads me to believe that many (most?)
have reached the same conclusions as I have.

That is:
Isolating the incoming antenna and control cables is the preferred
method. Providing a low impedance path to ground in the radio shack is
undesirable.

Further, adding an extra ground point in the system wherever is a
lightning no-no and introduces unknowns into the RF scheme. Especially
if one chooses to not run a 1:1 swr.

In my case the base of the tower has its own ground and is connected
to the structure lightning protection. I will continue to disconnect
and connect cables.

If an application that requires operation during electrical storms is
the norm, it becomes a different circumstance.

I will keep an open mind to the question though!
John W8CCW

On Sat, 29 Apr 2006 03:41:56 GMT, Sum Ting Wong
wrote:

On 27 Apr 2006 17:24:55 -0500, wrote:

I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.
John Ferrell W8CCW

I would follow the advice of TCLAY a couple of posts back. I would add
that there should also be a low impedance ground at the shack entrance
where the lightning arrestor is placed. At that same point the rest of
the radio equipment should be grounded. One common ground point for
all. The tower ground should also be run over to that common ground
point.
The AC power that supplies your equipment should have protection
devices that connect to the common single point ground also.

All grounds in the system should be tied together.

The idea of the single point ground is to have all equipment go up in
voltage together if there is a lightning strike and fall together.
This eliminates voltage differences between parts of equipment that
causes damage.

The coax shield should be grounded to the tower at the top and the
bottom of the tower. The tower should have a substantial ground system
of several ground rods and radials.

Look at the Polyphaser site again. They show how a single point ground
system should be installed.

73
Gary K4FMX


On Sat, 29 Apr 2006 14:38:22 GMT, John Ferrell
wrote:

The low response to the question leads me to believe that many (most?)
have reached the same conclusions as I have.

That is:
Isolating the incoming antenna and control cables is the preferred
method. Providing a low impedance path to ground in the radio shack is
undesirable.

Further, adding an extra ground point in the system wherever is a
lightning no-no and introduces unknowns into the RF scheme. Especially
if one chooses to not run a 1:1 swr.

In my case the base of the tower has its own ground and is connected
to the structure lightning protection. I will continue to disconnect
and connect cables.

If an application that requires operation during electrical storms is
the norm, it becomes a different circumstance.

I will keep an open mind to the question though!
John W8CCW

On Sat, 29 Apr 2006 03:41:56 GMT, Sum Ting Wong
wrote:

On 27 Apr 2006 17:24:55 -0500, wrote:

I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.
John Ferrell W8CCW

Thank you. Lots to read & consider there. It will take me a while to
digest it. Some how I managed to miss Polyphaser in my searching.

John, W8CCW

On Sat, 29 Apr 2006 13:25:25 -0400, Gary Schafer
wrote:

I would follow the advice of TCLAY a couple of posts back. I would add
that there should also be a low impedance ground at the shack entrance
where the lightning arrestor is placed. At that same point the rest of
the radio equipment should be grounded. One common ground point for
all. The tower ground should also be run over to that common ground
point.
The AC power that supplies your equipment should have protection
devices that connect to the common single point ground also.

All grounds in the system should be tied together.

The idea of the single point ground is to have all equipment go up in
voltage together if there is a lightning strike and fall together.
This eliminates voltage differences between parts of equipment that
causes damage.

The coax shield should be grounded to the tower at the top and the
bottom of the tower. The tower should have a substantial ground system
of several ground rods and radials.

Look at the Polyphaser site again. They show how a single point ground
system should be installed.

73
Gary K4FMX


On Sat, 29 Apr 2006 14:38:22 GMT, John Ferrell
wrote:

The low response to the question leads me to believe that many (most?)
have reached the same conclusions as I have.

That is:
Isolating the incoming antenna and control cables is the preferred
method. Providing a low impedance path to ground in the radio shack is
undesirable.

Further, adding an extra ground point in the system wherever is a
lightning no-no and introduces unknowns into the RF scheme. Especially
if one chooses to not run a 1:1 swr.

In my case the base of the tower has its own ground and is connected
to the structure lightning protection. I will continue to disconnect
and connect cables.

If an application that requires operation during electrical storms is
the norm, it becomes a different circumstance.

I will keep an open mind to the question though!
John W8CCW

On Sat, 29 Apr 2006 03:41:56 GMT, Sum Ting Wong
wrote:

On 27 Apr 2006 17:24:55 -0500, wrote:

I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.
John Ferrell W8CCW
John Ferrell W8CCW