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HT Antenna Modification For Increased
Performance! Edited and re-written from an
article entitled "Getting the Most from Your Hand-Held Transceiver"
by C. Edward Harris, KE4SKY, AEC Fairfax ARES
When limited to "barefoot"
operation, with a "rubber duck", HT antennas are not very efficient
nor adequate for communications. They fail miserably as an effective
radiator due to their design! They are nothing more than an extended
dummy load acting as an antenna! The following modification
will help you to make the most of your HT by increasing the
factory antenna's efficiency and the cost is just a piece of
wire!
FACTS ABOUT HT
ANTENNAS
The National Bureau of
Standards tests of Public Safety high band and amateur 2-meter
antennas indicate that a "rubber duck" has -5db, "negative gain"
compared to a quarter wave held at face level. In terms of effective
radiated power (ERP), this means that a 5 watt HT with rubber
duck, radiates only 1 watt. Operating an HT on your belt results in
another -20db attenuation, reducing ERP to 50 milliwatts! That's
1/20 of one watt! UHF results are no better...
Due to the design of the
factory installed HT antenna, you are effectively missing half of
the antenna!
MODIFY
THAT HT ANTENNA FOR BETTER RESULTS Get ready to use that scrap of
wire you have in your junk box! A simple, inexpensive and effective method to improve a
"rubber duck" antenna is by adding an external counterpoise or
"tiger tail" thereby adding the other "half".

It should
be noted that if your HT is under warranty, the internal
modification may void that warranty...you have been
warned!
Adding the other
missing "half": You can easily build one from a
quarter-wave piece, (about 19.5" on 2m, 11.5" for 220 and 6.5" for
440), of stranded insulated wire, crimped and soldered to a battery
clip or use a small spring tension clip that will fit the BNC
antenna connector with the wire attached to it. Use a clip or other
connection that fits tightly but can be removed if needed. It must
make both a good mechanical and electrical
connection.
Another method would be to attach the end of the
wire by soldering it to a grounded portion of the circuit board
inside the HT, although this may not be practical with some models,
or any point that is at ground potential on the HT such as the
"ground" side of an external speaker/headphone jack, the BNC
connector at the antenna, or the Negative side of the battery
terminal. The preferred location is at the
factory antenna base at the BNC connector. If you have some
other type of metal antenna connector the same applies.
Many
of the newer models don't lend themselves to internal modifications
easily. If the "rubber duck" antenna that came with the HT does not
come off, then you will have to make the connection inside the HT to
a grounded point. Extreme care must be taken to prevent shorting out
other components!!!!!! Use insulated
wire. You may have to drill a small hole in the case for the
exit point of the wire and tie a knot inside to provide strain
relief. Each installation will be different. Use your own
judgment!
Always reinforce the soldered connection with heat
shrink tubing or tape to resist flex and shorting to other
components if possible. When the counterpoise, (the other half
of the antenna), is clamped to the outer collar of the BNC
connector on your HT antenna, it helps to prevent RF from
coupling with your body, so your completed HT antenna
"system" acts much like a center-fed dipole instead of an
end-fed dummy load!
You just
built a directional antenna and did not know
it! In marginal conditions, extending the
counterpoise horizontally and pointing your hand to steer the
radiation pattern where you need it, produces a dramatically
stronger signal than letting it "droop" towards the ground.
Experiment with the angle of the counterpoise to get the best
results. In effect, you are creating a form of "V" type center fed
vertical dipole with a bit of gain compared to just the factory
installed antenna.
If you want to
buy another HT antenna, rather than add the counterpoise
described in this article, then it is recommended that you shop
around. Don't be misled by the cheaper priced antennas. Buy
from a reputable dealer that will answer your questions. Try to
find an antenna with published gain figures compared to a
dipole or 1/4 wave vertical. Don't expect Yagi or similar
performance....have fun and get better performance than
you were!
POWERED BY HAM
RADIO!
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