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Thread: Antenna shaft sections

  1. #1

    Default Antenna shaft sections

    Have you folks ever had portable radio shaft sections separate? (Not snap) I notice on a lot of the newer radios the interface between the shafts have a lot more slop or play.

  2. #2
    Super Moderator 5B4AJB's Avatar
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    Yes, the quality of most manufactured parts has declined, have a look on ebay for a replacement, you should find something adequate, if not the same quality.
    Take notice of the mounting point type and the total closed diameter & length, the other dimensions shouldn't matter...

  3. #3
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    quality aside often the ambient temperature can affect the manufacturing process (IE. hotter expands and cooler contracts)
    an item made in a warm climate will often shrink slightly in a cold climate and can cause unexpected headaches.
    when you couple the fact that manufacturing machines wear out and or go out of calibration, and quality control sampling may only be checking 1 out of a 1000

    collapsible shafts are designed for rapid or easy set up and tear down and the trade off is that the parts will wear out quickly eventually.
    Last edited by gnuuser; Sun 10th Jan 2021 at 17:16. Reason: spelling goofs
    Im so old dirt was my apprentice

  4. #4

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    Quote Originally Posted by gnuuser View Post
    quality aside often the ambient temperature can affect the manufacturing process (IE. hotter expands and cooler contracts)
    an item made in a warm climate will often shrink slightly in a cold climate and can cause unexpected headaches.
    when you couple the fact that manufacturing machines wear out and or go out of calibration, and quality control sampling may only be checking 1 out of a 1000

    collapsible shafts are designed for rapid or easy set up and tear down and the trade off is that the parts will wear out quickly eventually.
    Thatís weird because some guys I know say theyíve never had a collapsible antenna fail. One of these guys had over 300 radios. Any way to take good care for this not to happen? How about a tight shaft segment. (Not due to corrosion) on a newer radio.....

  5. #5

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    On a portable radio, how are each of the shafts held together?

  6. #6
    gnuuser's Avatar
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    usually there is couple of small copper shims inserted in holes at the bottom of each section that are stopped by the rolled in top edge.
    if one of these comes apart then the shims have broken off.

    on the telescoping mast's however there are 3 types of locking mechanism's
    external set screws, internal twist lock clamps, and compression gland clamps.

    twist lock type consist of a dick at the bottom of each section that is drilled off center twisting it will cam the disk out and bind inside the lower shaft.

    compression gland locks squeeze a copper or soft brass ring until it binds tightly against both the inner and outer sections.
    of the three the set screw types offer the strongest holding power (unless they are stripped out)
    Last edited by gnuuser; Mon 11th Jan 2021 at 21:52.
    Im so old dirt was my apprentice

  7. #7

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    Iím trying to picture the copper shins in the holes. Do they bust off often? Do you have a photo?

  8. #8
    gnuuser's Avatar
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    Quote Originally Posted by Frodge View Post
    I’m trying to picture the copper shins in the holes. Do they bust off often? Do you have a photo?
    i cant find a picture on the web but as best describes them
    one tube slides inside another a bit loose,
    then thin sheets of copper or brass are formed to fit between the inner wall of the lower tube and outer wall of the upper tube, the tubes have small holes drilled in the sides in which a small tab on the shim is inserted (to hold it in place)
    the shim takes up space and makes it tighter inside the lower tube,
    the top end of the lower tube is rolled in to stop the shim from pulling out the top.
    what usually happens is oxidation and corrosion build up on the shims and the stress from friction breaks off the tabs on the shim, once that happens the shim will drop out and the tubes will pull apart easily.

    Ive replaced numerous portable antennas on radios, older phones, rabbit ears on old tv's and such.

    while they do work well these antennas are rather cheaply made with very thin tubing.

    ill check my old junk drawer for an old antenna and post the picture of the shims.
    Last edited by gnuuser; Tue 12th Jan 2021 at 16:46.
    Im so old dirt was my apprentice

  9. #9

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    What i am about to suggest, i have not tried. I recommend testing it on a junk antenna first (ive tore all mine apart or i would).

    What if, a quarter inch from the rolled edge of each section at the top, a mini copper pipe cutter is used to slightly indent the outer tube such that when the antenna is extended, the shims on the bottom of the inner pieces meets the slightly indented part of the outer tubes as a means to make it tighter when extended? Gently as to not cut or crease the tube though. And make sure the sections are not fully extended when you try that so the shims dont get indents. A cheap dull cutter would be ideal.
    Last edited by brandon lind; Tue 12th Jan 2021 at 17:50.

  10. #10

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    Quote Originally Posted by gnuuser View Post
    i cant find a picture on the web but as best describes them
    one tube slides inside another a bit loose,
    then thin sheets of copper or brass are formed to fit between the inner wall of the lower tube and outer wall of the upper tube, the tubes have small holes drilled in the sides in which a small tab on the shim is inserted (to hold it in place)
    the shim takes up space and makes it tighter inside the lower tube,
    the top end of the lower tube is rolled in to stop the shim from pulling out the top.
    what usually happens is oxidation and corrosion build up on the shims and the stress from friction breaks off the tabs on the shim, once that happens the shim will drop out and the tubes will pull apart easily.

    Ive replaced numerous portable antennas on radios, older phones, rabbit ears on old tv's and such.

    while they do work well these antennas are rather cheaply made with very thin tubing.

    ill check my old junk drawer for an old antenna and post the picture of the shims.
    I found a photo on the internet of the shims. Iím guessing if I keep my food radios in a room thatís stable this is not as likely to happen. Iíve been using a long wire more often now anyhow. Are most antennas able to be found years later?

  11. #11
    gnuuser's Avatar
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    cut apart a junk antenna to get pics for him
    shim1.jpg
    shim2.jpg
    shim3.jpg
    It takes two of these shims to keep the shaft centered.

    its difficult to see but the end of the tube has two small holes drilled into it
    (crappy web cam)
    Last edited by gnuuser; Thu 14th Jan 2021 at 00:10.
    Im so old dirt was my apprentice

  12. #12

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    Thanks for the photos. It makes
    Everything very clear. Ideally I think it would be better to put a flanged or fluted end on each section like a fuel line.

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