How to attach a 1/8" brass rod stock to an SO-239 chassis mount connector?

Discussion in 'Homebrew and Kit Projects' started by WF7A, Oct 25, 2008.

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  1. W7WTO

    W7WTO Ham Member QRZ Page

    I used welding rod also and hammered the end flat then drilled a hole through it. Used screws and nuts to mount them to the SO239. I chucked up the center welding rod into my drill motor and filed it down in no time so it would fit into the center pin.
    The blacksmith method almost always wins out.
  2. K8ERV

    K8ERV QRZ Member QRZ Page

    OOOH! That might hurt!!

    TOM K8ERV Montrose Colo
  3. KD8CGF

    KD8CGF Ham Member QRZ Page

    Reducing rod stock for fitting a SO-239

    Quickest way to do this for a 1/8" rod not longer than 2" would be to chuck the piece in an electric drill, then wrap a bit of emery cloth or similar around the rod while spinning it in the drill. Burnt fingers possible here. Easier to over-remove material, stop & check frequently.
  4. W6GQ

    W6GQ Swap Meet Moderator Volunteer Moderator QRZ Page

  5. N1UVW

    N1UVW Ham Member QRZ Page

    How to attach a 1/8" brass rod to an SO-239

    "For the radials, get or make four substantial eyelets (used in electrical work); solder each radial to an eyelet and bolt each to the SO-239.

    Or roll the end of each radial into a loop (if the brass is ductile) and attach with nuts/bolts/washers."

    That's the way I also make my connection, But I'd like to pass a tip along with this. After you make your end connection you'll want to harden the brass rod. I chuck one end into a drill chuck and hold onto the other with vise grips and twist the rod about 8-10 revolutions.
    This does two things ,straightens the rod and cold rolls it in a sense, which adds a lot of strength . Try it on a scrap piece first you'll be amazed!. "73" from N1UVW
  6. W0HU

    W0HU Ham Member QRZ Page

    Ground Plane from SO239

    Having built quite a few of these for easily deployed portable antenna units, I found that if you form the end of the rod (for radials) around a 1/8" drill bit, then use a 1/8" x 1/4" long "pop" rivet, you can make a good solid attachment to the SO-239 (if it needs tightening, you can do it with a flat-ended punch). The other wisdom mentioned above for soldering the center to the radiating element is valid, try to not melt the white cheap plastic center. If you were fortunate to get the brown phenolic center, not to worry much. You can use 5 minute epoxy to seal the center if required, and work it to a taper so that water will run off. Your $2 antenna may cost you $5 if constructed this way.:cool:

  7. AE5JU

    AE5JU Ham Member QRZ Page

    Don't solder brass rod directly to the center. Instead, solder brass tubing. Available in almost any hobby shop and some hardware stores in the K&S brass rack. Less mass, easier to solder, lighter, so less strain.

    They make brass tubing in telescoping sizes.
  8. KD5ZPG

    KD5ZPG Ham Member QRZ Page

  9. KA7LGF

    KA7LGF Ham Member QRZ Page

    Don't Waste!

    Take a wood dowel & fit it into the back of a "PL259". Start with a Dowel a bit larger than the hole & see if U can, kinda "Screw" it in for a tighter fit. Now use a drill bit that fits into the center conductor to drill through the wood "Insulator" using the "Center Conductor" as a "Guide". I think it will be 1/8" same as Ur "Rod". If not, open up the hole from the back & then grind/file down the rod until it fits the "Center Contact Hole". Solder & that's done, ready to screw into the SO-239. Now, "Flatten" the Brass Rods ends to drill them for a screw & it's nut that fasten it to the SO-239. All done & it "Breaks Down" quick too! :cool: John KA7LGF
  10. KB1KIX

    KB1KIX Ham Member QRZ Page

    Lots of difficult methods here.

    I drilled a hole in the center of the plug, ran the LMR 400 (solid) right up through the middle.

    Radials as normal.

    Works fine 4 years now.

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