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best or acceptable wire size for dipole

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W2SAM, Jul 29, 2008.

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  1. W2SAM

    W2SAM Ham Member QRZ Page

    I am building a dipole and while pricing wire , I start wondering which is better for a dipole solid copper wire or stranded....14AWG or 12AWG or 10AWG ???

    my thoughts are that solid wire would be better , because the RF signal runs on the outside of the wire.....???
    the larger the wire the more braod banded the antenna will be ???

    thanks for any guidance
  2. WA9SVD

    WA9SVD Ham Member QRZ Page

    NEC specifies 14 AWG. for antennas. Most applications use 14AWG (or larger, such as 12 AWG) stranded copperweld wire, which will have the added strength of steel wire, as well as the conductivity of copper due to skin effect. there will be little (or noticable) difference in bandwidth of solid vs stranded wire of the same AWG.

    Niow, if you were comparing 14 AWG wire vs. 1/2" copper pipe, the bandwidth might be noticable, especially if you are comparing conductors at 2 Meters and above...;)
    Last edited: Jul 29, 2008
  3. AG3Y

    AG3Y Ham Member QRZ Page

    The difference in conductivity for solid vs. stranded copper wire is so small as to be un-measureable, at least by any methods a ham radio operator is likely to have in their possession.

    However, solid wire is more likely to become brittle due to flexing in the wind, and more prone to break sooner than equivalent stranded wire would.

    There are several types of copper wire available, in many different gauges. If you want to have the wire rather hidden, you obviously would need to go for some smaller stuff such as 16 or 18 gauge. But if you have no problem with that, you will want to go toward 14 or 12 gauge. Remember, the lighter stuff can stretch, twist and break, and the heavier stuff can cause problems just because of its size and weight.

    There is a type of wire that is very strong, and still conducts very well. I am referring to copper-clad steel cored wire. However this stuff is quite difficult to work with, as it tends to coil and kink unless you have a means to keep it stretched out as you work with it.

    For general all around use, I would probably stick with something like 14 ga stranded wire.

    SVD got his post published first. It is good to see that we agree!

    Hope this helps! 73, and welcome to the avocation. Jim
  4. WA9SVD

    WA9SVD Ham Member QRZ Page

    That's because we are GOOD! And we actually learned a lot over the years.:D:D:D

    Thanks for the added information .
    Last edited: Jul 29, 2008
  5. K3WRV

    K3WRV Guest

    I use 14, 16 or whatever guage I have available (or whatever's on sale). While diameter does have an effect on broadmanding the antenna, for HF, the difference between 18 and 10 will be pretty negligible. I've even used 17 ga Electric Fence wire ($8 /1/4 mi). But it's icky to work with / solder to.
  6. VE6RA

    VE6RA Ham Member QRZ Page

    Antenna Wire

    Some years ago I was fortunate enough to acquire some Down Rigger
    Stainless Steel Fishing line --approximately 2/16 Inch thick -it is not easy to work with but makes a perfect antenna --strong-won't break-won't rust-
    I am still using it for a G5RV Ant and have had several dipoles .Never any problems and it radiates excellently.

    If you have access to any sea going commercial fishing boats -their lines are changed frequently and the used line scrapped-Normally !!


  7. VE6RA

    VE6RA Ham Member QRZ Page

    Antenna Wire

    Should have added --this wire is not solid --it is braided--Sorry !!


  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    ::Glad it worked for you! But if it had been copper, depending on its length, it could be as much as 3 dB more efficient. Stainless steel is not a good conductor, and its skin resistance (for RF) at 10 MHz is about 4x copper. If it's a very short antenna, like a 2m dipole, probably not much difference. If it's a long antenna, like a 160m dipole, the difference is very measurable.

  9. WD5ABC

    WD5ABC Ham Member QRZ Page

    The electric fence wire is hard to work with if you get the galvanized steel but you can get aluminum electric fence wire and it's much easier to deal with. Not as easy to kink, etc. If all you can get is the steel wire, give it a shot, I've used it for years. If you experiment with antennas a lot, it's nice to have a cheap source! Don't worry about the guys who tell you the steel wire won't work, the skin effect is "thicker" on less conductive wire so it's almost a wash at HF for a normal dipole.

    The aluminum is probably a better choice if you can find it. I get it at Tractor Supply, I got some for FD and the 80m dipole I used fed with twin lead worked great.

  10. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    ::Kerry, where did that theory come from? Skin effect can't know what the conductor material is, unless you just invented something the scientific community never knew before...;)
  11. AG3Y

    AG3Y Ham Member QRZ Page

    It's GOTTA be TRUE, Steve ! I just read it on the INTERNET ! ! ! :eek: ;) :D
  12. W9GB

    W9GB Ham Member QRZ Page

    I have used a variety of wire types for building wire antennas (electric fence wire, solid Copperweld, Wireman's Silky, aluminum gutters, electrical wire, etc.)
    My preference after 35 years is 14 AWG stranded wire available at your local hardware store. It is readily available, flexible, and easy to use.
    Skin effect does occur, but the difference between solid and stranded wire is minimal for this usage.
    Correct, build a FAT dipole to achieve this effect (2 parallel wires spaced 12 to 36 inches apart from each other).

  13. AG3Y

    AG3Y Ham Member QRZ Page

    Actually, Greg, wouldn't a three dimensional "fat" dipole work better? I have seen the installation at W1AW, and they use at least 4 wires held together with crossed spreaders to form each side of the antenna. Maybe you could get away with three wires, but the spreader arrangement would probably be more difficult, unless you made them of equalateral triangles . HMMMMM there is an idea !
  14. VK2AKG

    VK2AKG Ham Member QRZ Page

    glass houses, we all live in them


    Steve, I thought you might like to have a look here:


    Jim, you may prefer to look in Microwave Engineering by AF Harvey (Library of Congress Catalog Card Number: 62-13097 ) which suitably pre-dates the internet having been published by Academic Press London & New York in 1963.

    On page 4 Harvey clearly states:

    "The skin depth is inversely proportional to the square root of the conductivity of the material. ..."

    73 Frank
  15. G4ALA

    G4ALA Ham Member QRZ Page

    Fatter makes Wider (BW)

    Just an observation.

    The bigger (greater diameter) the wire the larger the outer surface and hence the less the skin resistance will be.

    A great advantage of large diameter wire is that the bandwidth of the dipole is increased.

    Cage dipoles having several pieces of spaced wire on each side of the dipole held apart by spacers increase the bandwidth considerably.

    You probably only wish to have one piece of wire on each side.

    Aluminium alloy wire is light, strong, highly conductive, quite large diameter and readily available from most Ham stores (at least, over here in G-land). Ideal!

    If you want to go for the jackpot, try coaxial cable to make your dipole. The outer conductor is very large diameter, compared with most wire. However, co-ax is relatively heavy compared with most wire. It will sag under the sort of tension it can tolerate.

    But, that is not a problem. You can string up non-conductive rope to give mechanical strength and suspend the co-ax cable beneath the rope at intervals. Sorted!

    The question of "best wire" is seldom asked. It seems a very good question to ask.



  16. AG3Y

    AG3Y Ham Member QRZ Page

    "Jim, you may prefer to look in Microwave Engineering by AF Harvey (Library of Congress Catalog Card Number: 62-13097 ) which suitably pre-dates the internet having been published by Academic Press London & New York in 1963.

    On page 4 Harvey clearly states:

    "The skin depth is inversely proportional to the square root of the conductivity of the material. ..."

    73 Frank"

    Frank, I am always willing to learn something new. There must be other factors at play here beside the conductivity of the material. Your quote is from a microwave journal. Since there is no "skin effect" at DC, and unmeasurable skin effect at normal power line frequencies ( 60, 120 hz etc. ) I would be interested in knowing how frequency factors into the equation. I would love to see the rest of the quote, since it might be rather difficult for the rest of us to obtain that book. We do not all have access to major city libraries !

    73, Jim
  17. AI3V

    AI3V Ham Member QRZ Page

    Jim, I think you will find "skin effects" are quite noticeable at 60 hz. Copper busbar is rarely more than 1/4 inch thick,[usually, either 3" or 6" x 1/4] Thats the break-even thickness at 60 hz. And round or square cross sectioned Cu is "never" used (edit: for busbar).

    Last edited: Jul 29, 2008
  18. AI3V

    AI3V Ham Member QRZ Page

    And if this were not true, than nobody would use stainless steel antennas mobile, We would all use some sort of copper alloy!!!!

  19. AG3Y

    AG3Y Ham Member QRZ Page

    Rege, I am not disagreeing with you, because I obviously do not have expert knowledge in this area. But I do have another question.

    For years, McIntosh ( not the computer manufacture, but the audio component one ) wound their own audio transformers with square cross-sectioned copper wire. As you probably know, McIntosh components were considered some of, if not THE best audio components in the tube era.

    A McIntosh amplifier could pass an audio range of around 25 to 25,000 Hz, a frequency range of over 1000:1 with less than 1dB variation in power output.

    Now, obviously, there is a factor much larger than "skin effect" at play here !

    I'm thinking such things as inter-winding capacitance ( which the Mac engineers worked hard to minimze ) and cost factors ( which were not a real factor to those engineers, but would be in other applications such as RF Transmitter site grounding ) etc.

    A fascinating subject to discuss, but I sure would love to see the entire formula!

    73, Jim
  20. KR2D

    KR2D Ham Member QRZ Page

    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.
    Last edited: Jul 29, 2008
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