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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Tue 02, 2018 5:25 pm 
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Joined: Sep Thu 23, 2010 6:37 am
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Location: Powell River BC Canada
Lightning hits on telephone outside plant installations can travel down buried
cables and do a lot of damage. A solution is to bury a ground cable along side.

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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Tue 02, 2018 7:38 pm 
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Joined: Mar Sat 15, 2014 9:22 pm
Posts: 101
Considering that lightning is a dirty great spark traveling from the sky to earth, as has been said, a little knife switch won't help a lot. Some way to earth the aerial outside the house, and disconnect it from any lead in if there is a real danger, surely.


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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Wed 03, 2018 4:14 pm 
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Location: Leo, IN or Zellwood, FL
Leigh wrote:
Paul wrote:
Using an ohm meter, there is no DC continuity through the Polyphaser.

What does you ohmmeter say about the 2000-foot air gap that the bolt just jumped ?

Absolutely and totally useless...
And dangerous because it brings the antenna line into the house before any lightning arrestor.

- Leigh


Does your local TV station go off air when their tower it hit?
Does your local Radio Station go off the air when their towers are hit?
Does Ham Radio Station K9UWA go off the air when the towers are hit?

The answers to all the above are Only Momentarily they go off air until the power is reset after the event. Then the station is back on the air as if nothing had ever happened. My Hit Counter on the 180 foot tower says it has been hit 180 times as of last summer when I last looked at it. Damage to house, radio, computers and other electronics. ZERO The system has been place since 1989. The key here is properly designed Ground System. Mine has 100 ground rods and over 1200 feet of connecting copper tubing. That solves 90% of the hit being bled off to ground. The other 10% is taken care of nicely by Polyphaser devices. The Key here is don't miss anything that connects to anything else in the whole house. Any small relay wire rotor wire coax power line telephone line or antenna wire has to have some sort of proper protection device that takes whatever the line is directly to the common ground. In my system nothing is ever disconnected. The equipment isn't even turned off. It would difficult for me to reconnect or turn some of it back on from 1200 miles away from the home ranch. Yes I remotely operate the station.

Polyphaser turn BLITZ into BLISS
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John k9uwa

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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Wed 03, 2018 4:28 pm 
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Location: Leo, IN or Zellwood, FL
Chas wrote:
Poyphaser?

It is believed that the extensive damage is not from the hit itself but from a pulse that extends out and induces high voltage in metal objects, both above and below ground.
Chas


Chas a local small time example of this happened to a friend of ours. His place had a small 60 foot tower with antennas and he thought a complete proper ground system and protection devices. One time his tower was hit and the damage was to an Unplugged TV set that was setting on top of a 5 foot tall metal filing cabinet. After that happened he added a nice heavy wire from the filing cabinet to the common ground system and never had more damage to items left on or in the filing cabinet.
It would probably be impossible to do that with the are your describing.
John k9uwa

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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Thu 04, 2018 2:35 am 
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Posts: 31
I was always under the impression that lightning would strike the tallest object in the area and lower items would not take a direct hit. I am fairly sure I have seen drawings showing how something like an overhead power line will protect a large area near it. Unfortunately lightning must not have been well educated. It struck my neighbors driveway knocking out a sizable piece of concrete. The driveway is next to a two story house and surrounded by tall trees. There is also an overhead power line behind the house.

Tall buildings use something the size of a welding cable to ground their lightning rods and I suspect anything smaller is a waste of time.


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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Fri 05, 2018 7:35 am 
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Location: Tucson, Arizona U.S.A.
JnTX wrote:
I was always under the impression that lightning would strike the tallest object in the area and lower items would not take a direct hit. I am fairly sure I have seen drawings showing how something like an overhead power line will protect a large area near it. Unfortunately lightning must not have been well educated. It struck my neighbors driveway knocking out a sizable piece of concrete. The driveway is next to a two story house and surrounded by tall trees. There is also an overhead power line behind the house.

That used to be the theory, but, as you noticed, it isn't correct.

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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Sat 06, 2018 12:43 am 
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Location: Hamilton, Ontario
I have picked up all of the materials for the aerial but I just need the weather to break first; it's too cold for even a Canadian to be standing outside for too long! :wink:

I do have one final question though:

I found a good deal on some 14ga. stranded wire. $30 Canadian (about $25 US) for 1000 feet. Needless to say I now have lots.

Would there be any improvement in reception if, rather than one 70 foot run of wire, I ran two runs of 70 feet and soldered each of the ends together and braided them?

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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Sat 06, 2018 12:47 am 
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Jim Mueller wrote:
JnTX wrote:
I was always under the impression that lightning would strike the tallest object in the area and lower items would not take a direct hit. I am fairly sure I have seen drawings showing how something like an overhead power line will protect a large area near it. Unfortunately lightning must not have been well educated. It struck my neighbors driveway knocking out a sizable piece of concrete. The driveway is next to a two story house and surrounded by tall trees. There is also an overhead power line behind the house.

That used to be the theory, but, as you noticed, it isn't correct.

Whatever you think lightning will hit Well I think it follows Murphy's Laws

jason


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 Post subject: Re: Another Long Wire Antenna Question
PostPosted: Jan Sat 06, 2018 2:26 am 
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Location: Tucson, Arizona U.S.A.
jrs wrote:
I have picked up all of the materials for the aerial but I just need the weather to break first; it's too cold for even a Canadian to be standing outside for too long! :wink:

I do have one final question though:

I found a good deal on some 14ga. stranded wire. $30 Canadian (about $25 US) for 1000 feet. Needless to say I now have lots.

Would there be any improvement in reception if, rather than one 70 foot run of wire, I ran two runs of 70 feet and soldered each of the ends together and braided them?

I assume you mean connecting the wires in parallel. If so, it won't make any difference. A single 28 AWG wire will work as well. The only reason to use heavy wire for a receiving antenna is to have enough mechanical strength to withstand the weather. For a transmitting antenna, the wire has to be heavy enough to carry the current and to not have excessive losses. Even here, mechanical strength usually is the limiting factor.

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