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Thread: best or acceptable wire size for dipole

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  1. #41

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    Steve:

    The old FAA regulations required that any tower 200 feet above ground or higher (shorter if within certain distances from airports) had to be painted with 7 equal width bands of paint starting with red or international orange on the bottom then white alternating until the 7th band (the one on top) was red or orange. Then the regulations were changed to only international orange and white.

    Now days painting of the tower is not required if suitable strobe lighting is installed on the tower.

    At Texas A&M University (located in Bryan/College Station, Texas) the tower on campus had to be repainted and the regulations required international orange and white. However, the University painted the tower maroon and white which are the "colors" of the athletic teams. They refused to paint the tower international orange and white because those are the "colors" of their "arch rival", The University of Texas (located in Austin, Texas). The FAA threatened to levy fines on Texas A&M for painting the tower in a "unapproved" color scheme. It took a special bill introduced into Congress by former Senator Phil Gramm to get the maroon and white paint job approved instead of the international orange and white. Of course Phil Gramm had been a professor at Texas A&M before being elected to Congress which definitely did not "hurt" the University's case.

    Glen, K9STH

  2. #42
    Join Date
    Nov 2004
    Location
    Western Michigan. Great summers but nasty winters.
    Posts
    14,968

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    I have NEVER, EVER had a SOLID copperweld antenna break.
    Have you tried an end fed Zepp on a Harley-Davidson?
    73
    Mark, K8MHZ

  3. #43

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    >At Texas A&M University (located in Bryan/College Station, Texas) the tower on campus had to be repainted and the regulations required international orange and white. However, the University painted the tower maroon and white which are the "colors" of the athletic teams. They refused to paint the tower international orange and white because those are the "colors" of their "arch rival", The University of Texas (located in Austin, Texas). The FAA threatened to levy fines on Texas A&M for painting the tower in a "unapproved" color scheme. It took a special bill introduced into Congress by former Senator Phil Gramm to get the maroon and white paint job approved instead of the international orange and white.<

    ::That would be like asking UCLA to paint their tower Cardinal (red) and gold (USC's colors). Their tower is blue and gold (UCLA colors) and I have no idea how they got away with that. Possibly another "political influence" like your local one there...

    73

    Steve WB2WIK/6

  4. #44

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    If the tower has strobe lights it can be painted any color! Also, if the tower is under 200 feet above ground (with the aforementioned exceptions) it can be painted any color. Those are without "political connections"!

    Glen, K9STH

  5. #45

    Default What wire?

    I've seen dipoles made from everything from #12THHN house wire to #38 wire scavenged from a television deflection yoke. Yep, that was done by my roommate in college, in an effort to have an "invisibile" antenna. Worked fine until one cold day when it iced up and collapsed.

    Best thing is to find some copperweld wire -- this is steel wire with a copper coating. This won't stretch and detune, albeit it can be a pain in the fanny to work with. #12 to #18 will work just fine.

    Just try something and see if it works.

    Gary WA7KKP

  6. #46

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    Quote Originally Posted by n2jso View Post
    I was wondering if anyone used aluminum (or aluminium ) wire for antennas. It's not commonly available here except in very large sizes for high current circuits or mains service drops. It seems ideal for wire antennas because it costs less than copper and weighs much less. Precautions need to be taken for connections to minimize corrosion, but the correct hardware and anti-corrosion substances are readily available.
    Aluminum wire is certainly "usable;" (that's why many antennas such as Yagi's and HF verticals ARE constructed with aluminum elements) but it is NOT as conductive as copper, and the weight issue for wire of practical sizes is usually only a secondary consideration. Proper connections and prevention of corrosion are more important.

  7. #47

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    When needed, I will make antenna out of almost any available wire. I have a spool of 18 ga stranded bare copper [I have no idea what this was made for, I bought it at Home Depot] that's great for portable/field light duty use, I know people have used very small magnet wire for stealth purposes, I've used 16 GA hookup stranded insulated.

    Now, as to what I personally prefer to use:

    Fixed Antennas - home QTH, intended for permanent [ahem] installation: I use the hard-drawn Van Gordon stranded copper wire - it's strong enough for my 80/40 fan dipole top line, supporting the 40 meter wires below, and is easy enough to work with and not horribly expensive.

    IF my location allowed me to lay out the antenna on the ground before hanging, I would consider CopperWeld because of it's greater strength, but as noted, it's pre-hanging mechanical properties make it a chore to work with.

    Portable Antennas: For ease of handling, nothing beats the Davis RF products Flex Weave wire. Yea, it's expensive, and it's heavy but it's darn near impossible to kink which makes it really nice to handle in the field. I use the jacketed because the wire strands are so tiny that it's easy to snag them.

    I know that people get passionate about wire types and such. Personally, I say use copper when you can, and use ANYTHING that will work when you must, and it's it's a special case, use special materials - I have a trailing wire antenna for an airplane that is made of braided dacron with a phosphor bronze wire woven into it. Works fine for that job but is too expensive to use for ground antennas.

  8. #48
    Join Date
    Oct 2005
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    Default Re Stainless Steel 316 grade wire

    this wire is typically made up of 7x19 strands for say 2mm thickness - so that 133 strands of wire. This does a hell of a lot to reduce the resistance at RF frequencies. And in locations subject to high salt levels in the air (like where I live) the use of this wire, with stainless steel clamp fittings, is going to be highly preferable to something that will corrode badly over time.

  9. #49
    Join Date
    Aug 2005
    Location
    Canby, OR
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    2,127

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    When I lived on my parents' farm as a new teenaged ham, I bought a 250' coil of #12 solid Copperweld to put up a long wire. It was in a coil of about 5 inch inside diameter and bound with several bands of soft copper wire, spaced around the circle. I snipped the binding wires and suddenly there was a big SPROING!! and I found myself on the inside of a huge tangle of Copperweld, looking out. I finally was able to get it hung up in a straight line but have never since bought #12 Copperweld! That stuff is so strong that there is no need to go larger than #14, and I have used #16 for 80 meter dipoles with no problems.

  10. #50
    Join Date
    Mar 2006
    Location
    Newcastle, NSW, Australia
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    Default Re Stainless Steel 316 grade wire

    The multi-strand construction will not reduce the resistance of the wire; it will behave like a single 2mm wire.

    To achieve the "Litz" effect each strand must be insulated from its fellows.

    Litz wire only works at low frequencies; up to about 1 MHz or so.

    I hadn't seen the early posts on this thread before; if I had, I would have weighed-in to the skin depth discussion.

    Skin depth certainly does increase with increased resistivity of the conductor. See here, for instance;

    http://www.microwaves101.com/encyclopedia/skindepth.cfm

    It's enlightening to plug some numbers into the calculator;

    http://www.microwaves101.com/encyclopedia/calsdepth.cfm

    There is stainless steel and there is stainless steel; there are myriad cocktails of ingredients and those that contain lots of nickel have higher resistivity.

    Resistivity of 316 is about 74 x 10-8 ohms/metre; copper is about 1.72 x 10-8 ohms/metre.

    The result is that the skin depth in 316 is about six times greater than the skin depth in copper. This does not fully-offset the 43-fold difference in resistivities, esp. as the increase in cross-sectional area is not linear in a circular conductor, but it does have some offsetting effect.

    (I hope my maths is correct; it's early here on a holiday Monday and I need coffee!! )

    But, so far as using the 316 or any other non-copper material, I think that WOU's comment sums it up;

    "I know that people get passionate about wire types and such. Personally, I say use copper when you can, and use ANYTHING that will work when you must, and it's it's a special case, use special materials ...... "

    Well-said!!

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