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Thread: Homebrew Dipole Insulators

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  1. #21
    Join Date
    Sep 2001
    Location
    Vero Beach, FL
    Posts
    308

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    I like to cut up Lexan cutting boards inhto 1" strips. They make good insulators.

  2. #22
    Join Date
    Oct 2006
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    in a seaside village
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    2,066

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    In the past some hams would use paraffin-saturated wooden dowels as insulators for ladder line and wire antennas. Hams would boil the dowels in the paraffin until the rods were well permeated. The abundance of porcelain and PVC insulators renders this method obsolete. Also, wood will inevitably warp when exposed to moisture.

    73, Jordan

  3. #23

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    Quote Originally Posted by WA7PRC View Post
    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. Davis RF and some others sell porcelain compression insulators from small to large sizes.
    I thought that was the only kind of ceramic insulators available... OK, my mistake I wouldn't use an "egg" insulator for the CENTER insulator of a dipole. There ARE good quality ceramic insulators for dipole center insulator use.

  4. #24

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    "Dog-bone" ceramic insulators have been available since at least the 1850s having been used in land line telegraphy.

    Nothing wrong with using an "egg" at the center of a dipole. If, for some reason, the insulator fails the antenna will still be in the air. No difference in terms of wire overlap than when used at the ends of the dipole.

    Over the years, I have used "egg" insulators in the center of dipoles many times. No problems at all.

    The ceramic dog-bone insulator in the attached photo is at least 40-years old.

    Glen, K9STH


    007.JPG

  5. #25

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    Quote Originally Posted by WA9SVD View Post
    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.
    I have quite a few porcelain insulators myself.

    The plastic ones I have are actually quite good, and even heavier/tougher than the MFJ porcelain insulators I have. Currently supporting the wire top hat on my 160m vertical which is made up of bare solid aluminum wire.

    The suggestion was made because the operator was looking for household items. Unless he really likes cutting things up, its not worth his time.

    That was the point.

    Porcelain, or plastic he can buy them a lot cheaper than he can make them. I'd rather spend the time on a real project, or on the air. Not enough hours in the day to fool around making insulators.
    Charley K1DNR

  6. #26

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    Quote Originally Posted by K1DNR View Post
    ... and even heavier/tougher than the MFJ porcelain insulators I have.
    Daburn has been manufacturing them since dirt was new.

  7. #27

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    PVC pipe works just fine. So does plexiglass. Save your money and take your lady to a movie and dinner.

    A well attended to XYL or GF will view your radio fun with a lot less of a hairy eyeball if you make the time.
    Or you can get her interested in radio...
    It would really help new amateurs who want to build antennas to find an older copy of the ARRL Antenna book. There are too few explanations and too little data in the current editions. By old I mean say pre-1989. Cruise hamfest tables and Ebay, there are plenty available pretty cheap.

  8. #28
    Join Date
    Jul 2007
    Location
    South Carolina
    Posts
    65

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    Quote Originally Posted by N8WWM View Post
    PVC pipe works just fine. So does plexiglass. Save your money and take your lady to a movie and dinner.

    A well attended to XYL or GF will view your radio fun with a lot less of a hairy eyeball if you make the time.
    Or you can get her interested in radio...
    Actually mine just got her Tech License KK4ITV

  9. #29
    Join Date
    Mar 2011
    Location
    Waynesboro VA, US
    Posts
    1,003

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    Quote Originally Posted by AB2T View Post
    In the past some hams would use paraffin-saturated wooden dowels as insulators for ladder line and wire antennas. Hams would boil the dowels in the paraffin until the rods were well permeated.

    I read this and it made me think of another hobby of mine. Drop some leather in that bath as well and you'll wind up with some cuir bouilli armor! Don't use this method on footgear though!

    Back on subject, I got a nylon cutting board from the Dollar Store and plan on using that in bits for insulators.
    [SIZE=1][B]"An armed society is a polite society. Manners are good when one may have to back up his acts with his life." - Robert A Heinlein[/B][/SIZE]

  10. #30

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    Glass insulators for radio were also used
    http://www.cyberbeach.net/~dknetzke/...ss_strains.htm

    Corning Glass Works made Pyrex radio insulators at one time (through 1940s)
    http://glassian.org/Pyrex/index.html
    Wonder how much a Gorilla Glass insulator would cost today?

    The Insulator Store - Check price of colored glass insulators
    http://www.cyberbeach.net/~dknetzke/...ss_strains.htm
    Nullius in verba

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