I got a bit of a mystery with AIS
static data here, not sure if this is common? Someone has run into this before?
I installed an AIS
Class B transceiver on a boat that's in a marina 200m from where I work. It has a ~6' whip antenna
and 2 spliced co-ax cables
connecting it, I soldered the connections myself, for better or for worse. 20 minutes after powering it up, I get position reports from about 50 vessels but static reports (ship name etc.) from about 3-5 vessels. I'm missing a huge amount of static reports. At work, a few hundred meters away, our AIS receiver picks up about 100 vessels, all with static data too.
I was thinking maybe because I was in a marina surrounded by radio
obstacles that maybe the position reports were coming through because they were smaller, single-packet messages and less prone to inerfereance destroying them. The static data messages come in multiple packets so maybe there's a higher chance of one of them getting corrupted. I took the boat out into the middle of the commercial
harbour, within 2 miles of at least 50 vessels with AIS. Again, 20 minutes later, very few vessel names appearing.
But what's weird is I can pick up AIS position reports from ferries 18 miles away but no names from tankers 200 yards away.
So I thought maybe something was crazy with my DIY co-ax splices so I took a 2nd antenna
out there with an off-the-shelf cable. Same thing.
What's going on? Has anybody had this happen?
Thanks for any tips or insight!