Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old April 19th 05, 08:08 PM
RHF
 
Posts: n/a
Default

Dr Artaud & DX Ace,
  #2   Report Post  
Old April 22nd 05, 05:40 AM
 
Posts: n/a
Default

The Tips can be Elevated above ground or
the Tips can be at/near ground level and a
Ground Rod placed at both ends (Tips) with
a Lightning Aresster (GDT) mounted on each.
.................................................. .......

The higher the ends above ground, the better.
You have less earth loss. There is no need to
use lightning arresters at the tips of the dipoles
to ground. If the wire were actually close enough
to ground to arc to ground, it will do it, arrester, or
not. Being as you are not protecting any devices at
the ends, there is no real point in using arresters. The
arrester should be in the feedline leading to the radio.
If the inv vee is supported by a tree or mast, the lightning
is more likely to take that path to ground, than the path
of perpendicular antenna wires to ground.
Lightning doesn't like to take sharp turns. So you should
always ground the supporting mast well, if it's metal.
It's gonna take the brunt of the strike to ground...
Horizontal wire antennas are not near as prone to be a
lightning target, as say a vertical, or other tall mast.
IE: a dipole, or inv vee hung in a tree will add little to the
overall likelyhood of that tree being struck.
It would probably be struck anyway, antenna or not,
if lightning was that close, to choose that target. I bet in most
cases, the antenna would basically be untouched, unless the
strike found the feedline running down the tree, and decided to
use it....You can always snub the feedline to ground at the base
of th tree in a case like that. I know I have had two direct strikes
to my mast supported my various dipoles, and have never had
any indication of wire, or coax damage.
That tells me most of the strike is carried to ground
by the mast, which does stick up about a foot above my
antenna apex. "I currently have 160/80/40 dipoles on one
feedline...Appx 440 ft of wire in the air...The apex about 42 ft
high supported by a metal mast. So far, in 35 years of hamming,
SWLing, I've never had a horizontal wire dipole be a lightning
target. But mine are never higher, than surrounding
objects, trees, etc unless supported by a mast, or tree, which
then becomes a more preferred target than the dipole itself...
Not saying it can't happen. It surely can.
But not near as often as vertical targets.
Even at 42 ft, I've still got trees taller than that in the yard...
That helps...The last strike hit the tree in the front yard....
If the vertical target is well above the house, other objects, you
can bet on it taking a zap sooner or later. Most people don't
have wire antennas higher than the surrounding trees, etc,
unless they have a vertical support to support it...When they
get above the surroundings, is when their chance of a strike
goes up sharply. Even horizontal metal can be a problem if
it's really high...IE: beams, etc..MK

  #4   Report Post  
Old April 24th 05, 03:39 PM
Jack Painter
 
Posts: n/a
Default


"? Dr. Artaud ?" wrote

Thanks for the response. We just last night had another thunderstorm,
depositing plenty of noise and lightning nearby. Our house is physically
lower than the houses on either side, and the end of our yard has a very
tall Silver Maple tree, to which my random wire antenna runs from the
house. The wire ends about 7 feet from the tree trunk, and is tied to the
tree with the rubber strip that is used to hold screens in windows frames.
I fear that a strike to the tree will impart more than static to the

random
wire antenna.

Perhaps you, RHF, Jack Painter, or others can comment on how to protect

the
random wire from transferring a lightning strike to the tree from

following
the antenna wire. As I sleep by the radio, I don't with to be awakened
writhing from a lightning strike.

Regards,

Dr. Artaud


In my opinion, the best lightning arrestor products for up to 1.5 kw
transmission systems are made by Industrial Communication Engineers (ICE).

Solutions for either open-wire (no coax feed involved) or coaxial feedline
arrestors are shown at Array Solutions, the distributor for I.C.E.

http://www.arraysolutions.com/Products/ice/3.html

ICE also makes very convenient grounding blocks for the custom connections
of coax shield grounding. This allows a "manifold" connection of several
coax shield grounds to a ground rod and works very well. But Andrews and
Harger and others also make those, and Harger is probably the best for
grounding materials in general. Local electrical distributors will carry (or
order) Harger products.

Jack Painter
Virginia Beach, Virginia


  #5   Report Post  
Old April 24th 05, 05:12 AM
€ Dr. Artaud €
 
Posts: n/a
Default

"RHF" wrote in news:1113937736.278231.195640
@f14g2000cwb.googlegroups.com:

Thnaks for your comments. Please see my response elsewhere in this thread
concerning grounding needs.

Dr. Artaud

Dr Artaud & DX Ace,
.
The 'classic' Inverted "V" Antenna would usually
have a combined Top Apex Angle of 90* to 120*
or a Bottom Tip Angle of 30* to 45*.



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
NEC Section 810 Online? Jim Miller Antenna 10 April 8th 05 06:14 AM
Single ground Bill Ogden Antenna 26 November 25th 04 03:47 AM
Lightning Strikes Boat Anchor morris.verlander Boatanchors 1 June 13th 04 02:26 AM
Balun Grounding Question ? John Doty Shortwave 4 November 25th 03 12:29 PM
Antenna mount Jason Wagner Scanner 12 August 12th 03 09:02 AM


All times are GMT +1. The time now is 04:18 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017