2018-01-19, 03:06 PM
The external antenna is supplied by the BNC connector. You could use any GNSS dome antenna, however the integrated GNSS patch antenna is quite good. Depending on your boat material, you could even use the HAT below deck without the need of an external antenna.
The standard connector type for marine GPS antennas is either BNC or TNC. SMA is mostly used for the smaller antennas with magnetic plate. The BNC connector might be used up to 4 GHz, so no need to worry that it can't cope with GNSS frequency.
The SO-239 connector (standard for AIS antenna) is very big. This would have a not negligible impact on board size and would cause mechanical stress on the HAT, if the antenna is attached. In this case SMA is the better choice. There are SMA to SO-239 and SMA to BNC pigtails available anyway, so this is no big deal.
The standard connector type for marine GPS antennas is either BNC or TNC. SMA is mostly used for the smaller antennas with magnetic plate. The BNC connector might be used up to 4 GHz, so no need to worry that it can't cope with GNSS frequency.
The SO-239 connector (standard for AIS antenna) is very big. This would have a not negligible impact on board size and would cause mechanical stress on the HAT, if the antenna is attached. In this case SMA is the better choice. There are SMA to SO-239 and SMA to BNC pigtails available anyway, so this is no big deal.