These GPS antennas offer an alternative and secure installation to atraditional mag mount. With proper positioning in or on a vehicle,they enhance the performance of the GPS modem.GPS performance is 26 dB, with 5 dBi antenna gain. The GPS circuitryhas a low 2.0 dB max noise figure with excellent filter characteristics.Power (2.7 to 5 VDC) and signal is applied through the same cablingdirectly to the GPS antenna.The IW-1575 Glass Mount GPS antenna places the GPS elementdirectly against the glass of the vehicle, oriented up towards thesatellites. The cable exits near the top side allowing direct entry intoa vehicle headliner. The IW-1575 is designed to be mounted on theinterior of the window only.The SM-1575 hole mount antenna uses a 5/8" feed thru (16 mm) forsecuring to the vehicle. Access to the underside of the body surfaceis required to complete the installation. The antennas are enclosedin a weatherproof ASA radome, and supplied with all hardware andsealing gasket. The SM-1575 radome is 2.5" in diameter (64 mm)and very low profile. The SM-1575 radomes are available in white orblack.