Synergy Systems, LLC

All active GPS antennas include a built-in Low Noise Amplifier (LNA) which provides sufficient gain to overcome coax cable losses while providing the proper signal level to the GPS receiver.

See Synergy Systems, LLC Tech-Note TN-488 for Antenna to GPS receiver connection recommendations. This Tech-Note explains several ways to connect GPS antennas to the GPS receivers. Coax extension cables and coax cables for permanent mount antennas are also discussed.

Passive GPS antennas (also called substrates) do not include a Low Noise Amplifier (LNA) and are best suited to GPS applications requiring a short distance, 1 inch to 3 feet, between the GPS receiver and antenna.

Passive antennas require an LNA on the GPS receiver or mounting a separate LNA close to the RF input connector of a receiver that does not include an on-board LNA. The off-board LNA should be specified to provide additional gain to the substrate's basic gain figure (about 3 dBic or 4 dBic) so that the GPS signal presented to the GPS receiver is in the optimum gain range.

Synergy Systems offers antennas for GSM, CDMA, and VFH frequencies. We also offer combination cellular and GPS antennas.