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Marine Antenna Mounting Safe Distances
Garmin® marine electronics can use many different antennas ranging from GPS, VHF, Differential, and Radar. There are recommended distances to mount each antenna from another antenna.
Below is a table that will specify the recommended distance for mounting various antennas. These recommendations were taken from the National Marine Electronics Association (NMEA) Installation Guidelines.
| Intersecting cell identifies minimum spacing between antennas of given types in feet and/or reference to table notes. | VHF | GPS | Differential | SSB | Radar | Satellite Communications | LORAN | Cell Phone | Satellite TV |
| VHF | 4 | 3 | 1 | 3 | 2 | 6 | 1 | 2 | 3 |
| GPS | 3 | ½ | 1 | 4 | (a) | 6 (e) | 2 | 5 (c) | 2 |
| Differential | 1 | 1 | ½ | 4 | 3 | 10 | 2 | 1 | 1 |
| SSB | 3 | 4 | 4 | 10 | 3 | 6 | 3 | 2 | 4 |
| Radar | 2 | (a) | 2 | 2 | (b) | 6 | 3 | (a) | 4 (d) |
| Satellite Communications | 6 | 6 (e) | 10 | 6 | 6 | 6 | 6 | 6 | 6 |
| LORAN | 1 | 2 | 2 | 3 | 3 | 6 | ½ | 2 | 4 |
| Cell Phone | 2 | 5 (c) | 1 | 2 | (a) | 6 | 2 | 3 | 4 |
| Satellite TV | 3 | 3 | 1 | 4 | 4 (d) | 6 | 4 | 4 | 4 |
| ADF | 6 | 1 | 1 | 6 | 4 | 10 | 4 | 4 | 4 |
NOTES:
(a) GPS antennas, satellite TV antennas, or cell phone antennas shall not be installed in the direct beam of a radar antenna. The GPS antenna shall be raised above or mounted below the radar transmit beam
(b) Radar antennas shall not be installed in the same vertical height as another radar antenna. Sufficient vertical spacing shall be provided to ensure that the transmitting antenna of the radar is separated a minimum of 18 inches in height from another radar
(c) Cell phone transmission can interfere with GPS reception if the cell phone transmit antenna is in proximity to the GPS receiving antenna
(d) Spacing of satellite TV antennas from radar antennas will depend on output power of the radar. Higher output radars (6 kW, 10 kW, 25 kW) require greater spacing to avoid interference
(e) GPS antennas shall be mounted below the transmitted beam of SATCOM antennas