CB/Ham Radio Base Station Antenna
(210-0969)                 Installation               Faxback Doc. # 38507

Your Radio Shack CB/Ham Radio Base Station Antenna comes in three
easy-to-assemble sections and covers far above and below the traditional
CB channels.

You can also use your antenna for international, commercial, and 10-meter
amateur radio operation with up to 2000 watts.  Twin ring tuning makes it
easy to tune the input to the antenna for the optimum standing wave ratio
(SWR) over a range of frequencies.  The antenna is designed as a half wave
over a quarter wave variable mutual transductance tuned antenna.


Before you begin installation, read this manual and the separate
Consumer Product Safety Commission information sheet.  For your safety and
convenience, plan each step of the installation in advance.


    When you install an outdoor antenna, use extreme caution.
    If the antenna starts to fall, let it go!  it could contact overhead
    power lines.  If the antenna touches the power line, contact with the
    antenna, mast, cable, or guy wires can cause electrocution and death.
    Call the power company to remove the antenna.  DO NOT attempt to
    remove it yourself!


We recommend you assemble the antenna on the ground in a flat, open area.
Follow these steps to assemble the antenna using the supplied hardware.

1.  Slip a 3/8-inch lockwasher over the threaded end of the small top 
    section, then turn that section clockwise and connect it tightly to the
    middle section.

2.  Slip a 1/2-inch lockwasher over the threaded end of the middle section,
    then turn that section clockwise and connect it tightly to the bottom 


Using the supplied hardware, you can easily mount your antenna to a mast
(not supplied), a building's vent pip or other stationary object.


    For the best performance, mount your antenna at least 9 feet above the
    roof of the nearest building and 18 feet above or away from any metal
    object or structure.

1.  Place the supplied U-bolts (F) around the bottom section of the
    antenna and the mounting location.

2.  Slide a clamp (G) over each U-bolt, then slide a lockwasher (H) over
    the end of each U-bolt.

3.  To fasten the U-bolts in place, tighten the supplied hex nuts (I)
    tightly over the ends of each U-bolt.


    Be careful not to overtighten the hex nuts, otherwise you might damage
    the antenna.

    Do not use caulk or silicone sealant around any part of your antenna,
    otherwise moisture might not drain properly from around the antenna.
    This could damage the antenna or cause it to work improperly.


Follow these steps to prepare your antenna, and tune it with an SWR meter
(not supplied) for use with radio equipment.


    Your antenna is pre-tuned to the middle of the CB band (27.205 MHz)
    for the lowest SWR (standing wave ratio).  No tuning is necessary to
    use your antenna with a CB.

1.  Look up the frequency you use most often in the frequency/Antenna
    Length table on Page 6, then carefully measure and cut off the
    recommended length of the antenna's top section.

    IMPORTANT!  Be sure you cut off only the length recommended to operate
    on the desired frequency.  If you cut off too much of the antenna, you
    might need to replace the antenna's top section to receive some lower
    frequencies.  If needed, you can purchase a replacement top section
    through your local Radio Shack store.


    No cutting is needed to operate your antenna at 10-40 meters if you
    use an antenna tuner.

2.  Using an SWR meter, check the SWR at the top and bottom of the band.


    If you are using a watt meter, the meter should read full output power
    at the transmitter, and (after calibration) in the SWR position, SWR
    should be low (preferable 2:1 or less).

    The best place to check SWR is at the antenna's coaxial connection.
    You can also check SWR at the transmitter's coaxial connection.

3.  If the SWR is higher at the top of the band than it is at the bottom,
    turn both tuning rings (A) 1/4- to 1/2-turn clockwise to lower them.

    If the SWR is higher at the bottom of the band than it is at the top,
    turn both tuning rings 1/4- to 1/2-turn counterclockwise to raise


    For frequencies higher than 31.571 MHz, position the tuning rings at
    the top of the threaded section, then skip to Step 5.

4.  Repeat Steps 1 and 2 until the SWR reading is the lowest possible at
    both ends of the band.

5.  To lock the tuning rings in place, turn the top ring clockwise and the
    bottom ring counterclockwise, so they rest tightly against each other.


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