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Homebrew Dipole Insulators

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N4DCT, Apr 28, 2012.

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  1. N4DCT

    N4DCT Ham Member QRZ Page

    Where can I get insulators or how can I make them without ordering online from places like Gigaparts?
  2. WA6MHZ

    WA6MHZ Premium Subscriber QRZ Page

    I just took a hunk of board and drilled a coupla holes in it. Cost? Absolutely FREE!
  3. AD6KA

    AD6KA Ham Member QRZ Page

    I've drilled holes in 3" or 4" long scraps of 1/2" to 1" PVC pipe
    to make wire insulators.

    Every DIY'er has scraps of those around, or ask a neighbor.
    or use wood, as posted above. (If I lived in a REALLY rainy
    area, (>50 inches/year) and used wood, I'd throw a couple coats of
    Marine Spar Varnish on them. But that's just me.

    IF your wire antenna is going to be long, heavy, or high up
    in the air (pain to get up and down) then consider "Strain Relief"
    type insulators
    . A Google Search will find you designs you can copy
    in your shop.

    Some may say "UV Rays will make the PVC brittle and crack".
    Not in my experience, I live in So Cal: Hot, Dry, Sunny, almost
    all year round. Never had a PVC failure due to WX.

    73, Ken AD6KA
  4. AB9LZ

    AB9LZ Ham Member QRZ Page

    Plastic plumbing tee's make for good center insulators. Never had one fail in a decade of use.

    73 m/4
  5. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    I love this page from the army field manual on communications:

  6. K8ERV

    K8ERV Ham Member QRZ Page

    You might check electri fence insulators, I'm not too familiar with them.

    TOM K8ERV Montrose Colo
  7. K9STH

    K9STH Ham Member QRZ Page

    PVC pipe 1/2-inch in diameter costs like $1 for a 10-foot section here in the Dallas, Texas, area. Depending on the length, you can get a LOT of insulators from a single 10-foot section. Just drill a 1/8th inch, or so, hole through the pipe about 1/2-inch from each end. Pipe in either 3/4ths inch diameter or 1-inch diameter is a little bit more but still not anywhere near being expensive.

    The white PVC for my swimming pool pump has been exposed to the Texas sun for right at 30-years. Absolutely no chalking or other damage. Years ago, PVC pipe was subject to ultra-violet but anything made in the past over 3-decades seems to be fine.

    Glen, K9STH
  8. NA7U

    NA7U Ham Member QRZ Page

    I usually use PVC cuz it's handy, but it really should be painted to prevent UV damage (most of my antennas don't stay up long enough for that to happen, though, always experimenting ...). Zareba makes some good and cheap UV-proof fence insulators in various sizes. I've used them to build ladder line, but they'd be fine for antenna support. I really prefer glass/ceramic insulators because I think they are classier. The HW stores around here have lots of them and they are not expensive at all (after all you only need 2-4 of them). The cheapest way to do this is to simply solder loops on the end of your wire and directly attach the rope!
  9. K1DNR

    K1DNR XML Subscriber QRZ Page

    These are $1 a piece. Sold by many vendors and on EBAY. No drilling/cutting/sanding required.

    Attached Files:

  10. WA7PRC

    WA7PRC Ham Member QRZ Page

    Davis RF is my supplier of choice. They stock Daburn porcelain compression (aka "egg") insulators, as well as just about anything else you might need for a wire antenna. You can make insulators out of anything insulating that's strong enough but, unless you need a boatload of them, you won't save much.
  11. K8JD

    K8JD Ham Member QRZ Page

    Those electric fence insulators have a hole thru the center for screwing them to wooden fenceposts and a groove around the outside to wrap a fence wire around. I don't see any use for them for a dipole !
  12. K8JD

    K8JD Ham Member QRZ Page

    MFJ sells end insulators for about a buck a piece in six packs.
    The center insulators offered by many dealers are too pricey for me and I made mine out of a square piece of plexiglass with holes drilled in the proper places to secure the element wires and coax.
  13. NA0AA

    NA0AA Ham Member QRZ Page

    Never really came up with any clever insulators since I find the commercial ones cheap enough for me, but any sort of PVC pipe drilled should work - if it's really big stuff, you can cut it into strips. I'd paint it just to kill the white.

    Wood works as well.

    Any sort of plastic that is mechanically strong enough although in time UV exposure might destroy it.

    Cheap and quick? Zip ties in a loop - now I know that won't last very long - even black zip ties in sun crack pretty fast.
  14. WA9SVD

    WA9SVD Ham Member QRZ Page

    If I'm going to BUY ready made insulators, whether from ePay or a retail dealer, I'd prefer true ceramic insulators. They do NOT degrade with weather or UV exposure, and are far, far better insulators (physically and electrically) than plastic. Under tension, wire will eventually "cut through" plastic insulators, leading to failure. Consider the voice of experience.
    Most of the plastic insulators sold by Rat Shack and similar sources may be fine for a temporary (Field Day?) antenna (and we all know how temporary antennas tend to become permanent!) or SWL antennas with small gauge wire.
    Last edited: May 6, 2012
  15. WA7PRC

    WA7PRC Ham Member QRZ Page

    Exactly. Also, when a strain insulator fails, the wire falls, leaving the end of the support up in the air. That's why I prefer compression (aka "egg") insulators. When they fail, the wire is still supported, and the insulator can be replaced much easier. [URL="]Davis RF[/URL] and some others sell porcelain compression insulators from small to large sizes.
  16. K0BG

    K0BG Platinum Subscriber QRZ Page

    Here's a few things to think about. If you run low power, and your living area isn't damp you can get by with just about any insulating material. However, if you run high power, or live in a wet part of the country, the end insulator in question needs a long arc length. This rules our most egg insulators used as they should be—in compression. Great for guys, lousy for antennas.

    Most decent end insulators (remember, that's where the high RF voltage is) have several ring/groove cuts to increase the arc length. The longer the better too. Even the old HiGain "5 kV" insulators will arc over in damp weather even with moderate power.

    As I said above, at low power you can get by with anything. But out there at the and of a dipole fed with one kW, PVC (especially the gray material) is not the stuff of champions.
  17. WB5WSV

    WB5WSV Ham Member QRZ Page

    I bought some "P-4H-75D PORCELAIN STAND-OFF INSULATORS" from Fair Radio. They are ceramic, about 4 inches long, are threaded internally for a mounting screw and cost about $1.50 each.

    When I next take leave of my senses and venture into my attic to string a longwire antenna the length and width of my house, I plan to use them as stand-offs to isolate it from the wood structure.

  18. WA4OTD

    WA4OTD XML Subscriber QRZ Page

    In 1976 I used to just cut up plastic milk jugs. They always broke within a year or so, but they were readily available and easy to cut with scissors.......
  19. WA7PRC

    WA7PRC Ham Member QRZ Page

    I've been using the Daburn #10-72 compression (so-called "egg") insulators for 42 years at the kilowatt power level on the ends of dipoles and other hi-Z (high voltage) points, in the Great Pacific Northwet. ZERO flashover problems. Ever.
  20. N0LWF

    N0LWF Premium Subscriber QRZ Page

    Go to your local farm store and get some electric fence insulators. It's all I use since I am a farmer and have 100's laying around.
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