Extending the Range of Your Handheld With an External Antenna

Extending the Range of Your Handheld With an External Antenna
Extending the Range of
Your Handheld
With an External Antenna
January 17, 2009
Steve Gallafent WG7S
Handheld Pros and Cons
The Pros
Low entry cost
The Cons
Portability
Limited transmit
power
Easy to power
Poor antenna
Handheld Communication Range
Two components of range:
How far does my signal reach?
You can't communicate if you can't be heard
What can I hear?
You can't work what you can't hear
What Can I Hear?
Several factors affect what you can hear:
Signal path to the other station
Antenna gain
Other antenna issues
Radio capabilities
Signal Path
Signal path affects both the strength of signals
you receive and the perceived strength of the
signal you transmit.
Height
Obstacles
Antenna Gain
Antenna gain (or loss) is a measure of the effect
the antenna has on the signal.
Handheld antennas are often referred to as a
“dummy load”
A good base antenna can increase signal
strength by nearly 10x
Other Antenna Issues
Antenna performance is also affected by objects
in the “near field region.”
The most common object in the near field
region of a handheld is YOU
Calculating Antenna Gain
Antenna gain is expressed in decibels (dB)
Decibel scale is logarithmic
0 dB = 1x (Unity gain)
3 dB = 2x
10 dB = 10x
20 dB = 100x
Gain=10
Gain dB
10
Calculating Antenna Gain
Radio catalogs often use different suffixes with
dB to qualify the gain.
dBi = Relative to an isotropic radiator
dBr = Relative to a reference antenna
Antenna Connectors
Handheld radios typically use two different
antenna connectors
SMA (about 75% of radios on the market)
BNC (about 25% of radios on the market)
Antenna Connectors
Using an external antenna will probably require
some kind of adapter that allows you to connect
your antenna to the SMA connector on your
radio.
Limit wear from repeated
connection cycles
Reduce strain on the
connector
Antenna Selection
There are two approaches you can take to
increasing the capability of your handheld
antenna.
High-gain whip antenna (attached to radio)
External antenna
Antenna Selection
High-gain whip antennas
Antenna Selection
High-gain whip antennas
Easy to replace existing antenna
Attached to radio – No need for external cables
or changing connections
Can put strain on antenna connector
Make your radio much larger
Can introduce some flutter
Antenna Selection
Mobile antennas
Antenna Selection
Mobile antennas
Typically designed for use with a ground plane
Easy to set up and take down
Often available with different mounts
Magnet mount
Trunk lip
Design your own from an existing mount
Antenna Selection
Base station antennas
Antenna Selection
Base station antennas
Large (5 feet to 25 feet)
More difficult to move and set up
Highest gain
Signal Path
An external antenna can improve signal path.
Get your antenna up higher
Get the antenna away from obstacles
Separate your antenna from local noise
sources
Antenna Gain
An external gain antenna improves your ability to
transmit and receive.
Higher gain means that your transmitted signal
is stronger
Higher gain means that you can receive
weaker signals
Position the antenna for optimum performance
without having to change operating position
Issues to Consider
Base station installations
Convenience
Lightning protection
Antenna mounting
Issues to Consider
Portable installations
Ease of setup and take-down
Mounting methods
Typical usage scenarios
Stability and safety
Example Installations
Arrow Dual Band J-Pole
Example Installations
Arrow Dual-Band J-Pole
Example Installations
Arrow Dual-Band J-Pole
Example Installations
Arrow Dual-Band J-Pole
Example Installations
Arrow Dual-Band J-Pole
Example Installations
Example Installations
Questions?
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