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Author Topic: Antenna wire  (Read 517 times)
W2BLC
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« on: May 21, 2004, 05:46:48 PM »

I need very strong insulated wire for antenna construction. Several multi-strand PVC/vinyl covered wires are available - but, I do not know what will withstand my weather conditions:

Winds in excess of 80 MPH, icing to two (2) inches, temperatures to -30 degrees, insulated for protection from acid rain.
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K0CWO
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« Reply #1 on: May 21, 2004, 06:02:11 PM »

Go to the following website:

              http://www.w7fg.com/ant.htm

These antennas are made out of black insulated 16 AWG wire.  If you don't mind open wire feeders they make a great ready made antenna that covers all bands with a tuner.  My doublet is 70 feet in the air and survives 72 mile per hour winds and 30 degrees
below 0 Minnesota winter weather.

Give the guy a call and discuss you needs with him.

Good luck!

BJ
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W0FM
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« Reply #2 on: May 21, 2004, 06:04:25 PM »

Wow Bill!  That's some nasty weather.  Have you considered a fan dipole in the attic?  So far, my attic antenna has never blown down or iced up ;-)

Terry, WØFM
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W8MW
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« Reply #3 on: May 21, 2004, 06:48:41 PM »

For wire antennas the baddest, toughest stuff out there is steel wire coated with copper.  A famous brand name is CopperWeld. I've been using #14 solid for years and continue to be amazed at how it survives under worst case situations. The bad news, it's more difficult to install than soft copper because it has a "spring memory" and will try to re-coil itself when you have a loose end.  Once you see how it acts and remember to keep some tension on it while measuring and cutting, it's  manageable.  When you get it in the air it is not going to stretch or break.  It'll stay there until a weaker component lets go (such as tie off ropes or wimpy insulators).  Highly recommended for a lasting installation.

73, Mike W8MW
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AA4PB
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« Reply #4 on: May 21, 2004, 07:09:59 PM »

Why does it have to be insulated? #12, solid copperweld is very strong. Steel core with copper plating. It won't stretch and it won't break easily but it is not insulated. It's available from AES.

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W2BLC
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« Reply #5 on: May 21, 2004, 08:54:30 PM »

Insulation is needed to protect the wire from acid rain. All exposed connections will be sealed. The idea is to get the antenna up and forget it for many years.
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KE4MOB
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« Reply #6 on: May 21, 2004, 08:55:28 PM »

Be warned though...#12 AWG solid copperweld is HEAVY.

But it is indestructible.  I've seen it hold up felled trees without breaking.
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AA4PB
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« Reply #7 on: May 21, 2004, 09:13:15 PM »

My opinion is that #12 copperweld will hold up longer, even without the insulation, than most other wire with insulation - especially when it comes to ice. I wouldn't worry about the acid rain - although I would solder and attempt to seal any connections.
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W8MW
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« Reply #8 on: May 22, 2004, 08:43:21 AM »

Agree with PB and MOB.  We have been getting a lot of wind storms in Ohio and I've had trees uprooted while watching the copperweld antenna act like nothing is happening.  Last year a heavy tree limb broke off and landed on top of one leg of my 80 meter dipole.  The copperweld did not break while the added stress caused the center support mast to lean 45 degrees.  Fortunately the mast is 2 inch heavy wall aluminum and it straightened out when the stress was relieved.  This was with #14 solid copperweld.  I have also used #12 and it's a monster alright.  Too tough to bend without pliars and challenging to work with but it sure means business.  
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K0BG
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« Reply #9 on: May 22, 2004, 09:23:13 AM »

Actually, the toughest stuff is ACSR (aluminum conductor, steel re-enforced). This is what power companies use for overhead wires. There is a draw back, however. The smallest size available is #6 awg and only comes in 1,000 foot or longer reels. Its tensil is in excess of 25,000 pounds.

Alan, KØBG
www.k0bg.com
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WIRELESS
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« Reply #10 on: May 22, 2004, 12:35:12 PM »

Hams seldom consider using a 'messenger' cable to hold up a dipole.  It works well because the messenger is small gauge steel wire broken with insulators and can be as strong as you want with the copper antenna wire of your choice riding along under it.

Decades ago in the military, I put these kinds of antennas up and not one ever broke. The antenna was always # 6 wire since antenna currents can be very high with even 500 wats to 1kw.  All hams express concern over transmission line losses but never consider that there are loses in antenna wire.
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W3JJH
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« Reply #11 on: May 22, 2004, 07:04:23 PM »

Using wire lighter than AWG14 for spans as long as an 80 m dipole is not allowed with by the National Electrical Code.
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AA4PB
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« Reply #12 on: May 22, 2004, 10:40:42 PM »

For a 1/2 wave dipole, the resistive losses in #12 or #14 copper wire is very small compared to the radiation resistance. That means the loss is pretty insignificant at legal amateur power levels.

If you use a messenger cable, it better be broken up into relatively small pieces with lots of insulators (or made of a non-conductive material) if you don't want it to become part of the antenna due to coupling.
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K0ZN
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« Reply #13 on: May 24, 2004, 02:57:59 AM »

Hi,

Just a word of advise, based on experience in military and marine HF communications. ALL antennas REQUIRE periodic inspection and maintenance. Some will go longer than others, but something hung out in the rain, hail, "acid rain", and endlessly buffeted, twisted, and "worked" by the wind SHOULD be periodically checked. It is hardly a big job to lower an antenna once a year in the fall on a nice day and check it over and make corrections and repairs BEFORE it is 5 degrees above zero with a -25 F wind chill!
I would suggest spending a little less on an "overkill" antenna wire and a little more on a convenient, reliable pully system to make it quick and easy to lower the antenna now and then for a check up.
Sea going HF antennas are often made up of a bronze wire cable that is about AWG # 4.... really tough and really expensive stuff. I would also second the comment about copper plated steel....VERY strong stuff for ham use, but over time, the copper plating will deteriorate and you can get rust, so even though this wire is very strong, it won't last "forever". At my QTH we get wind gusts in excess of 75 mph, radial ice, and endless wind... and I have had NO problems using basic # 14 hard drawn copper wire. I have seen a ton of ice on that stuff, but it doesn't break... just don't tension it like a piano string! How you tension the antenna can have a lot to do with it's mechanical reliability. Use good quality end insulators too; cutting corners here is counter productive.

73,  K0ZN
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KA3NXN
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« Reply #14 on: May 25, 2004, 01:13:25 PM »

Check out www.radioworks.com I know they carry the stuff you are looking for. I replaced the wire on one of their antennas with their insulated harsh environment wire when I lived in So. Florida. The winds off the ocean and salt air just tore the antenna apart. Once I replaced the wire with the heavy duty insulated wire it never broke again. It survived hurricane Andrew back in 92. Take it from me that was a whole lot more than just 80MPH.

73's & good luck KA3NXN
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