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?