Easy to build 2 meter antenna

Discussion in 'General Technical Questions and Answers' started by N6OSB, Aug 11, 2007.

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  1. N6OSB

    N6OSB Ham Member QRZ Page

    Good morning,

    I want to built and outdoor antenna for my 2 meter radio. I've seen copper j-poles but I don't have all the tools for it. I'm not sure how much I would have to invest in tools to built it.

    What antenna can a built that would work as good as the coper j-pole? But that would not require a huge investment in tools. BTW I've never done any coper work. I have done small amounts of soldering.

    I would be up for building a dual band antenna in case I upgrade my radio. I currently have a Yaesu Memorizer as my home rig.

    This antenna looks interesting but there isn't any step by step instructions:
    DBJ-1

    Do you guys have any suggestions?
     
  2. KC0W

    KC0W Premium Subscriber QRZ Page

    It does not get any easier than this: 2 Meter Vertical

    Total cost?............MAYBE $2


    Tom kcØw
     
  3. KA0GKT

    KA0GKT Ham Member QRZ Page

    The 1/4-wave ground-plane Tom suggests is the simplest 2-meter antenna which you can biuld, and it works pretty well. It ought to get you into many local repeaters.

    As far as step by step instructions for the twin-lead j-pole, it is juste a matter of measuring, cutting and soldering. Ed Fong, the author of the article, last I heard is a professor at U.C.Berkeley, so you might actually be able to have a QSO with him and get answers direct from the author; alternatively, you could contact him via e-mail at: edison_fong@hotmail.com.

    Good luck with your first antenna project. Both are worthy of your attention, and tons of fun. In this day when few Amateurs home brew their transmitters or receivers, an antenna is a good way to roll your own.

    73 DE KAØGKT/7

    --Steve
     
  4. K8JD

    K8JD Ham Member QRZ Page

    Looking at the antenna link from KC0W, you can simplify it even more by eliminating the nuts and bolts ( you would need a wrench and screwdriver)... Using only a fair sized soldering iron, just solder the radial wires to the holes in the so-239 flange!
     
  5. KA9VQF

    KA9VQF Ham Member QRZ Page

    If you are a home owner, the tools needed to build a copper j-pole are really minimal and a good investment anyway.

    The most expensive part would be the propane torch.

    Burns-o-matic still sells their basic one for around $10.00 if you keep your eyes open when you go to the big box stores you may find one for even less, my younger brother just picked one up last month for $6.99 at Lowe’s.

    Next you would want a tubing cutter. I got one at Wal-mart this spring for $2.99.

    Add some solder and you are pretty well set.

    I have a tool for cleaning copper tubing with that was my dads. It has round wire brushes inside holes for cleaning the outside of the tube and two straight ones on either end for cleaning the inside with, they go for around $8.00 but I don’t need a new one the old one is fine.

    You can also use almost anything to make the copper shiny and ready to solder including SOS pads, hand held wire brush, sandpaper it really doesn’t matter all that much. I’ve actually used my pocket knife upon occasion.

    The solder really doesn’t make that much difference either. I like to use the silver bearing acid core for building copper antenna with. But any 60/40 solder will work for you.

    The last roll of silver bearing solder I got last spring cost $6.00 at Home depot. You might want to invest in rosin core solder of a bit smaller diameter so you can use it in electronic repair though. I just seem to need the bigger stuff for plumbing all the time anyway.

    It really isn’t that hard to sweat a joint. I like to get it all clean then put a dab of rosin soldering paste on it then heat it just until the rosin starts to spank then add the solder.

    You need to watch your heat. The worst thing I see most novice solderers do is get the copper to hot. When you do that you can ruin the copper and the solder turns into some kind of amalgamate that is no longer good solder.

    Oh the joint may hold up and even be usable as an antenna but you don’t want that if you are doing plumbing.
     
  6. KG6YTZ

    KG6YTZ Ham Member QRZ Page

    I'm going to disagree with that statement.  [​IMG]  IMHO, it can NOT possibly get any simpler [more simple?] than a 1/2-wave dipole made from the coax itself.  Strip about 19 inches [234/f for 2m] of the outer insulation, separate the braid and center conductor - this is the only difficult part. and probably requires pulling the center through a gap in the braid, which should be made without cutting the braid - and there you go.  About 19 inches of braid and center conductor = Instant Dipole.

    Of course, this is a quick-and-dirty solution and is not particularly well-suited for permanent outdoor use, especially not without doing some weather-sealing at the feedpoint to keep water out of the coax.  In an emergency, though, it WILL get you on the air, and it can be build with no tools but a pocket knife if you're really desperate.  [​IMG]
     
  7. N3EF

    N3EF Ham Member QRZ Page

    If you decide to build this one, I would suggest adding a 1 Megohm resistor from center pin to the flange (ground) to drain off static. This antenna is highly susceptible to static build-up. Iv'e built a couple of these and had one connected to a rig in my shop. On a dry winter day, it began to snow and I heard a snapping sound coming from the rig. I disconnected the coax and with the open end laying on the bench, it began to arc across the connector about once every 30 seconds! Since then, Iv'e always used a bleeder resistor.

    Eric N3EF
     
  8. K0CMH

    K0CMH Ham Member QRZ Page

    I agree that the tools to make the copper j-pole is about as cheap as one will find antenna building tools.

    The only think I would add is a small container of soldering "past" (actually called flux). This adds about $2.00 - 3.00.

    The tubing cutter is the way to go. All the home improvement and hardware stores carry them.

    Also, if you don't have a yard stick or tape measure, that will be needed.
     
  9. W5OTR

    W5OTR Ham Member QRZ Page

    i agree.  Here is my 1 penny, weather proof version:

    1/2 mile of fence wire at Home Depot is 13.00.  So, That is enough to make about 1500 two meter dipoles.  That is 4/5th of a cent for 1 dipole, but we'll round up to 1 penny.

    Add some scrap piece of coax and some Schneider Duct tape (from work) and you have a 1 penny dipole...

    or if you'd rather:  a 15.00+ dipole.. haha...

    <a href="http://cgi.ebay.com/2-Meter-2M-Amateur-Ham-Radio-Dipole-Antenna-144-MHz_W0QQitemZ110158320419QQihZ001QQcategor

    yZ4672QQssPageNameZWDVWQQrdZ1QQcmdZViewItem" target="_blank">http://cgi.ebay.com/2-Meter....iewItem</a>
     
  10. KA0GKT

    KA0GKT Ham Member QRZ Page

    Be sure to mount it vertically for FM use or endure the 27+ dB cross polarization signal loss. If you do mount it vertically, remember to run the transmission line away from the antenna for a minimum of 1/2 wavelength (approx. 3' at 2-meters...1-wave is even better)

    73 DE KAØGKT/7

    --Steve
     
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