em-trak B300 AIS

[seattleboatguy]

I noticed today that the em-trak B300 AIS transponder might not need an external antenna. They say...


"The internal high-performance GPS with advanced redundancy
is complemented by a unique internal GPS antenna which means
that in certain installations no external GPS antenna is
needed."

Any idea which "certain installations" can skip the external
antenna?

 

[kchace]

I noticed today that the em-trak B300 AIS transponder might not need an external antenna. They say...


"The internal high-performance GPS with advanced redundancy
is complemented by a unique internal GPS antenna which means
that in certain installations no external GPS antenna is
needed."

Any idea which "certain installations" can skip the external
antenna?

A guess would be installations that put little between the device and a clear view of the sky. Usually, GPS signals go through fiberglass pretty well. So if the device was placed high up on the boat with not much more than a thin fiberglass skin between it and the sky it should probably work ok. But one would have to test to be sure.

Ken

 

[Cigatoo]

I believe you will still need a VHF antenna or minimally a splitter and an existing VHF antenna. The new GPS units seem to work fine under fiberglass as stated above.

 

[seattleboatguy]

A guess would be installations that put little between the device and a clear view of the sky. Usually, GPS signals go through fiberglass pretty well...
Ken

I confess I'm a little ignorant concerning AIS. When your chart plotter tells you there is a tugboat 2 miles ahead beyond a blind turn, is your AIS receiver getting that information directly from the tug's AIS transmitter, or does all the data come and go via the satellite?

 

[kchace]

I confess I'm a little ignorant concerning AIS. When your chart plotter tells you there is a tugboat 2 miles ahead beyond a blind turn, is your AIS receiver getting that information directly from the tug's AIS transmitter, or does all the data come and go via the satellite?

The data is encoded in the Tug's AIS transmission which is a VHF transmission.

https://www.navcen.uscg.gov/?pageName=AISworks

Ken

 

[Fletcher500]

That link provides a good summary. Wiki also has some details, including the differences of Class A and B systems. AIS is worth the investment, you will like it.

 

[drb1025]

I mounted my AIS in a cabinet in the pilot house and it’s gps works very well without an external gps antenna.

 

[South of Heaven]

We installed an emTrak AIS transceiver last summer ( I can't remember if its the B100 or B300). We DID install a separate VHF antenna for it.

I love the emTrak. It works perfectly and was easy to set up. The bang for your buck is amazing too.

 

[Cigatoo]

I confess I'm a little ignorant concerning AIS. When your chart plotter tells you there is a tugboat 2 miles ahead beyond a blind turn, is your AIS receiver getting that information directly from the tug's AIS transmitter, or does all the data come and go via the satellite?

In short your AIS (transceiver) is downloading your GPS position and transmitting it out to others over VHF. It is also receiving other AIS transmissions through VHF from other vessels.

 

[Mako]

I installed an Emtrak B100 in my boat (required by law here) and it was self contained and battery operated. Unfortunately it was transmit only. But it seemed to work adequately.

The one thing about an internal antenna is that it's not going to have the same range as with a traditional external high gain whip. Of course in local situations that is not really a big issue, and I would think that AIS is most useful in close situations anyway.