DMGibson
New member
Sorry to bring up this topic again, but does anyone have any real experience of using the NASA AIS receiver and plotter?
It seems to me that the main benefit is that it can actually show you the name and callsign/MMSI number of ships, so at least you can actually identify the ships and if necessary talk to one of them. This was always going to be the problem with GMDSS, as an "all ships" call on channel 16 would not be hear, as no-one monitors it (in theory at least).
The main problem with it is that it only has a single VHF receiver, so it can only listen to one of the two frequencies. The screenshot on the NASA web site shows the user has the option of selecting which channel to receive, and NASA have confirmed that it only receives one or the other, not both. Doesn't that mean it misses half the broadcasts, and if so does it miss actual ships which then don't show on the display?
The spec for the system fitted to ships calls for two independant receivers which can monitor both frequencies at the same time, so it seems to me that the NASA unit could be missing something.
It seems to me that the main benefit is that it can actually show you the name and callsign/MMSI number of ships, so at least you can actually identify the ships and if necessary talk to one of them. This was always going to be the problem with GMDSS, as an "all ships" call on channel 16 would not be hear, as no-one monitors it (in theory at least).
The main problem with it is that it only has a single VHF receiver, so it can only listen to one of the two frequencies. The screenshot on the NASA web site shows the user has the option of selecting which channel to receive, and NASA have confirmed that it only receives one or the other, not both. Doesn't that mean it misses half the broadcasts, and if so does it miss actual ships which then don't show on the display?
The spec for the system fitted to ships calls for two independant receivers which can monitor both frequencies at the same time, so it seems to me that the NASA unit could be missing something.
