How to make antenna for a Weather Radio

Discussion in 'Electronic Repair' started by JoseGomez@dotcom.com, May 14, 2011.

  1. Guest

    I got a Midland WR-100 weather radio. Because I live in a metal sided
    house, the reception is poor. On the back there is a RCA jack for
    external antenna. I can easily make up a piece of coax with a RCA
    jack on the end, but what should I use for an antenna. I'd prefer to
    make something simple out of wire, such a a straight piece of wire or
    dipole type wire, strung under the roof of my deck, or a piece of
    stiff wire pointing upward. I do have some old CB car antennas that I
    could modify too, and mount them on the deck or rain gutter. I know I
    could likely buy something, but I'd like to keep the cost down. I'm
    not needing to boost the signal as much as to just get the signal from
    the outside into the house due to the metal siding.

    Simple and cheap are what I want.
    And redardless of that I use, can I use common TV antenna type coax,
    or do I need the stuff that was used for CB radios. (I dont recall
    the numbers used on them, but know they were not the same).

    Thanks in advance.
    , May 14, 2011
    #1
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  2. wrote:
    > I got a Midland WR-100 weather radio. Because I live in a metal sided
    > house, the reception is poor. On the back there is a RCA jack for
    > external antenna.


    > Simple and cheap are what I want.
    > And redardless of that I use, can I use common TV antenna type coax,
    > or do I need the stuff that was used for CB radios. (I dont recall
    > the numbers used on them, but know they were not the same).


    Use RG-6 (TV coax). If you have any left over, you can make a large (12")
    loop out of it, anywhere along the way, so you might as well get a length
    already cut with connectors attached. The connectors will be "F" connectors
    for TV's etc.

    Buy an F to RCA adaptor, but I doubt that it's an RCA connector. It's probably
    a MOTOROLA connector that looks like a long RCA one. A Motorola connector
    will fit in (and stick out) of an RCA jack, but not vice versa.

    My experience with places like radio shack is that you will have to buy
    an F to UHF adapter and then a UHF to Motorola. Maybe not, ask. Radio Shack
    has lots of motorola plugs and adaptors, but their web site is not indexed
    well and I don't feel like paging through them all.

    As for the antenna, you can buy one, or make a simple ground plane or
    dipole antenna. For example, a simple dipole would be two 18 inch aluminum
    tubes, separated with about an inch of plastic rod. Connect each side of
    the coax to one rod, and stack them vertically. You can put plastic caps
    on the ends of them to prevent water getting in, but don't paint them.

    You can play around with the location, orientation (horizontal or vertical)
    and direction of the antenna for best results.

    Geoff.

    --
    Geoffrey S. Mendelson N3OWJ/4X1GM
    Occam's Razor does not apply to electronics. If something won't turn on, it's
    not likely to be the power switch.
    Geoffrey S. Mendelson, May 14, 2011
    #2
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  3. Phil Allison Guest

    <>
    >
    >I got a Midland WR-100 weather radio. Because I live in a metal sided
    > house, the reception is poor. On the back there is a RCA jack for
    > external antenna. I can easily make up a piece of coax with a RCA
    > jack on the end, but what should I use for an antenna. I'd prefer to
    > make something simple out of wire, such a a straight piece of wire or
    > dipole type wire, strung under the roof of my deck, or a piece of
    > stiff wire pointing upward. I do have some old CB car antennas that I
    > could modify too, and mount them on the deck or rain gutter. I know I
    > could likely buy something, but I'd like to keep the cost down. I'm
    > not needing to boost the signal as much as to just get the signal from
    > the outside into the house due to the metal siding.
    >
    > Simple and cheap are what I want.



    ** Use an indoor TV antenna - the kind with a pair of telescopic rods for
    VHF reception.

    Spread the rods wide apart and set each to about 18 inches long - get an
    extension antenna lead if you need to and an adaptor for the plug to go to
    RCA.

    Should all be fine if kept out of the rain.


    ..... Phil
    Phil Allison, May 15, 2011
    #3
  4. Michael A. Terrell wrote:
    >
    > It is 50 ohm, not 75.


    Doesn't matter. RG-6 has taken over the low end coax market, it's well made,
    cheap, easy to find and can be gotten in regular, direct burial and
    long distance hanging (with attched steel wire) versions.

    For reception, the difference in impedance is meaningless and many hams are
    using it for transmitting. Most hams use it for transmitters of 100 watts or
    less, but some have reported using it for 500. (ouch).


    > It is a RCA/Phono connector. I have the same unit. Use the right
    > connector if you want good reception. You can see it in the photo of
    > the rear panel on page 5.


    That's a lot easier. I have RG-6 compression RCA connectors. Strip the
    coax with simple tool, trim the center conductor and squeeze. I bought
    50 of them off of ebay including the compression tool for $50.

    F to RCA adapators are easy to get an cheap.


    > A VHF ground plane cut for 162.475 MHz will cover the VHF frequencies
    > used by NOAA: 162.40, 162.425, 162.45, 162.475, 162.50, 162.525, 162.55
    > MHz
    >
    > There is a sketch on the NOAA website showing the proper dimensions:
    > http://www.erh.noaa.gov/cae/images/antenna.gif



    Ground planes are more difficult to make, he asked for cheap and simple
    and a dipole will do it. Almost anything from 15 to 20 inches a leg
    will do. I picked 18 as it's a foot and half and simple to measure and make.
    Making it out of tubing instead of wire makes broadband enough that it will
    cover all of his VHF scanning needs.

    Two meter ham band antennas, of which I've made many, need to be 19 inches,
    so 18 is close enough for 162mHz, and is simple. If the person building
    it buys 3 feet of tubing, and cuts it in half, it will work well.


    >
    > The NOAA transmitters use vertical polarization.


    Good to konw, and it probably will be what he needs, but he may have
    reflections, hills, buildings, etc in the way so it always is better to
    try than not.

    Geoff.


    --
    Geoffrey S. Mendelson N3OWJ/4X1GM
    Occam's Razor does not apply to electronics. If something won't turn on, it's
    not likely to be the power switch.
    Geoffrey S. Mendelson, May 15, 2011
    #4
    1. Advertising

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