[KYHAM] KEN Training for Sept. 9: Getting the Most from Your Hand-Held, Part 2

[Ron Dodson]

Getting the Most from Your Hand-Held Transceiver (Second in
a 3 Part Series)
�1998-2002 Virginia RACES, Inc. Nonprofit reproduction
permitted with source attribution By Ed Harris, KE4SKY,
Virginia RACES State Training Officer 

Antennas

Some after-market and home-made antennas perform much better
than the standard helical "rubber duck." A J-pole antenna
constructed of  300-ohm twin-lead rolls up and fits into
your pocket. When thrown up in a tree, it increases both
height and gain.  Full-sized, flexible 1/4 wave and
telescoping 2-wave antennas work very well.

A quarter wave provides unity gain when used with a
counterpoise and held at face level.   This represents a 5
dB improvement over a stock flexible antenna, because most
of the effective signal is radiated.   If operating from a
vehicle, connect your portable to a magnetic mount mobile
antenna to provide a clear RF path outside the vehicle. 
This overcomes the substantial attenuation, which results
from operating a portable unit from inside a metal vehicle. 
Always carry suitable adapters so that you can connect your
portable transceiver to an outside base or mobile antenna,
when one is readily available.

In marginal operating locations a telescoping, half-wave is
much better, because it provides the same unity gain without
a ground plane that a 1/4 wave antenna does when used with a
ground plane.  A 2-wave antenna can be pulled up into a
tree, dangled out a window, attached to a window pane with
suction cups, or be used bicycle or motorcycle mobile, or in
city driving on a window clip mount.  A telescoping
half-wave increases useable simplex range of a typical 5
watt, 2-meter portable from about a mile with the stock
flexible antenna to 3 miles or more, depending upon 
terrain.  Adding a counterpoise to a unity gain antenna
enables a portable unit to keep in reliable contact within 5
miles of an EOC or base station also equipped with an
elevated, gain antenna on a tower.

Telescoping antennas are more fragile and work best when
stationary or in the open, avoiding side impacts or rough
handling.  Avoid prolonged mobile use of telescoping
antennas on window clip mounts at highway speed, because
excessive flexing loosens their internal electrical
connections.  Never collapse a telescoping antenna by
whacking it down with the palm of your hand. Gently pull it
down with your fingers.  If you note any wobbling or
looseness, replace the antenna. 

Flexible antennas are safer when working in close quarters
around people and are more durable when walking through
dense vegetation for wildfire suppression or search and
rescue operations. They are better for dual-band
transceivers
because telescoping antennas are usually mono-band.  
Dual-band flexible antennas approximate a 1/4 wave on 2
meters and a 5/8 wave on 70 cm, are optimized for one band
and may resonate poorly on the other.  How efficient a
particular antenna is can be determined only by testing.   A
telescoping half-wave, or half-wave, dual-band-mobile
antenna with magnetic mount, will work well either with or
without a ground plane, and offer the best bang for the
buck.  

Any emergency antenna for your portable transceiver much be
rated to handle up to 25 watts of RF output. This enables it
to be used as an expedient antenna for a mobile radio in
portable operation, or to permit use of an external "brick"
amplifier with your portable transceiver. 

A magnetic mount works best on a car, but an improvised
ground plane can almost always be found around the home or
office, such as a metal filing cabinet, metal trash can,
cookie sheet, rain gutter, refrigerator, window air
conditioning unit, balcony railing or any other large metal
object.   On boats, motorcycles, fiberglass truck caps or
wooden balcony railings use a half-wave antenna, which does
not require a ground plane.