1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

Help a newb build a Yagi

Discussion in 'Home Brew' started by W4LKR, Jun 25, 2012.

  1. W4LKR

    W4LKR Member

    Joined:
    Jun 25, 2012
    Messages:
    21
    Likes Received:
    0
    After watching Moleculo's how-to video on working AO-51 with a handheld I'd like to build a Yagi for 2m/70cm satellite work. I'm new to antennas, but not to techy DIY projects in general.

    I've already figured out how to program my FT-60R to TX/RX split band. Being new to ham radio in general I'm not clear on whether I need a duplexer built onto the Yagi. Arrow and others sell them this way, but isn't my FT-60R already taking care of it as-is? In other words, all I want to do is replace the stock antenna with a Yagi. So if it works as-is, shouldn't it work with the Yagi connected instead of the rubber duck?



    Thanks!
     

  2. W4LKR

    W4LKR Member

    Joined:
    Jun 25, 2012
    Messages:
    21
    Likes Received:
    0
    Disregard my previous question, further reading cleared it up.

    Building a 2m/70cm Yagi seems pretty straightforward. I am having trouble sourcing a device to mount on the antenna that will detect when the radio transmits and switches between the two antennas as appropriate.
     
  3. AudioShockwav

    AudioShockwav Extraterrestrial Admin
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    6,707
    Likes Received:
    3,729
    You need a 2 meter/440 duplexer
    Have a look here:

    NCG Company::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    The Arrow Hand held Antenna has a duplexer built into the handle.
    One coax to the radio into the duplexer, and two connectors out of the duplexer, one to your 2 meter antenna, and one to your 440 antenna, there is no "switching " it uses band pass filters inside the duplexer to split the signal.

    73
    Jeff
     
    #3 AudioShockwav, Jun 25, 2012
    Last edited: Jun 25, 2012
  4. W4LKR

    W4LKR Member

    Joined:
    Jun 25, 2012
    Messages:
    21
    Likes Received:
    0
    Thanks Jeff, I appreciate the clarification and link for the duplexers. I also found this which looks like a good and cheaper option:

    2m/440 duplexer on ebay

    I'm thinking of soldering it inside a project box from Radio Shack and adding coax connectors.

    The PDF guide to building inexpensive Yagi antennas recommends copper tubing for the driven element. I can get plenty of it fairly cheaply from onlinemetals.com. Is it okay to use the same material for the reflector and directors? Or is it better to use a different metal?

    Thanks for your help!
     
  5. AudioShockwav

    AudioShockwav Extraterrestrial Admin
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    6,707
    Likes Received:
    3,729
    The copper should work just fine as long as it is stiff enough to hold it`s shape


    73
    Jeff.
     
  6. W4LKR

    W4LKR Member

    Joined:
    Jun 25, 2012
    Messages:
    21
    Likes Received:
    0
    I'm wondering if either of these would be okay for the driven element, directors and reflectors? I found 1/4" copper tube and also some 9 gauge steel wire at Lowe's. Economical, but how difficult would it be to straighten it? Do they need to be perfectly straight?

    [​IMG]


    [​IMG]
     
  7. AudioShockwav

    AudioShockwav Extraterrestrial Admin
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    6,707
    Likes Received:
    3,729
    I have used 1/4 inch tubing just like that for a 2 meter yagi i had built several years ago.....i used it for all of the elements because it was what i had on hand at the time and it worked just fine.
    It is easy to work with.


    73
    Jeff
     
  8. W4LKR

    W4LKR Member

    Joined:
    Jun 25, 2012
    Messages:
    21
    Likes Received:
    0
    How did you straighten it? Maybe that's a dumb question, I just mean did you bend it by hand and eyeball it, or did you make up a jig or was there a trick to it? I assume it does not have to be as perfectly straight as a prefab copper pipe.
     
  9. AudioShockwav

    AudioShockwav Extraterrestrial Admin
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    6,707
    Likes Received:
    3,729
    Yes i just bent it by hand, it is fairly soft and did not take much effort, it is easy to work with.
    I was not using it for a hand held antenna so i did not worry about it getting bent while in use.
    Now that I think about it that is probably the advantage to the Arrow antenna that uses shaft`s for the elements as they are sturdy in use.
    I think Lowes/HD sells hard copper tube in straight lengths that might be more suitable for what you are thinking about as the rolled stuff is fairly soft.


    73
    jeff
     
  10. W4LKR

    W4LKR Member

    Joined:
    Jun 25, 2012
    Messages:
    21
    Likes Received:
    0
    Thanks that's a good point. Now I'm leaning towards ordering some 3/16" aluminum rod or tube from onlinemetals.com for all elements.

    Another question popped up after I watched some how-to videos on building more substantial yagis for permanent setups. The resonance of the feedline is emphasized, and yet I see very short feedlines for connecting handheld yagis to handheld radios. Is resonance less important when connecting an external antenna to a handheld? I ask because one example video has something like 20 feet of coax because that length was resonant at 2m. But again, all the handheld yagis I've seen connected to handheld radios have very short feedlines, like two or three feet.

    Thanks for sticking with my thread. This has been very helpful!
     
  11. Kiev88CM

    Kiev88CM Member

    Joined:
    Aug 30, 2012
    Messages:
    19
    Likes Received:
    2
    This may be too late but tubing bender at Home Depot. Copper tubing is annealed to be soft and flexible but , once you're done with your bends heat it and let it slowly cool and it will get hard.
     
  12. WA8ZYT

    WA8ZYT North Florida

    Joined:
    Feb 21, 2012
    Messages:
    201
    Likes Received:
    37
    I get all my aluminum tubing for antenna elements from DX Engineering.

    They have all kinds of stuff for constructing antennas. Prices and shipping are very reasonable.
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!