If averaged over 10 minutes or so, maybe 4800 would offer enough bandwidth
in certain locations, but you just cannot risk that say 20 (long) AIS
sentences are received more or less simultaneously. There is no way 4800
baud (1/8th!! of 38400) will handle that. Any idea how much traffic one
can expect say in the English Channel? It's the worst case scenario that
counts, not the average in Charleston harbor.
plano

"Larry" wrote in message
...
"plano" wrote in
:

I'm surprised the Cap'n can pass through (relay) AIS NMEA sentences,
but who is going to read them at 4800baud? All equiment that accept
AIS do this at 38400.
Also, if there is dense AIS traffic, you would soon run into bandwidth
problems running at 4800, the very reason why AIS uses 38400.
plano




Listen to your VHF radio tuned to the two AIS channels. The traffic is
bursts of data with LOTS of dead time. At some point, you're right, it
could become saturated. But 4800 baud would handle the data I've heard
coming over the two channels very easily in busy Charleston harbor.

Larry
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