Baud rates!!!!!

[ghostlymoron]

My pal has a raymarine plotter (large), icom radio and ais (unknown make). The position data is not shown on the dsc. Apparently the radio and ais need different baud rates and the plotter can't do both at the same time. Any solutions? He's planning to fit an additional gps dongle but that seems inelegant to me.

 

[sailorman]

my ais works on 38400

 

[pvb]

Any solutions? He's planning to fit an additional gps dongle but that seems inelegant to me.

The additional GPS source is probably the simplest solution, and introduces an element of safety as a second GPS. Otherwise, a multiplexer could be used to convert the plotter's 38400 output to 4800baud for input to the radio (something like the MiniPlex Lite would do the job).

 

[Tony Cross]

The additional GPS source is probably the simplest solution, and introduces an element of safety as a second GPS. Otherwise, a multiplexer could be used to convert the plotter's 38400 output to 4800baud for input to the radio (something like the MiniPlex Lite would do the job).

+1

 

[prv]

Additional GPS puck dedicated to the radio seems more elegant to me - why should the radio depend on the plotter? Seems logical to me that you should be able to turn either on independently.

Otherwise there are various converters that should work, but will be more expensive than a BR-355 GPS with either a home-made 12v->5v converter or Angus's YAPP board which does the same thing.

Pete

 

[AngusMcDoon]

...or Angus's YAPP board which does the same thing.

New website plug...

http://www.yappelectronics.co.uk/GPPS.htm

 

[nimbusgb]

Or disconnect the GPS from the Raymarine plotter and connect it to the radio.

If the AIS has its own GPS then it *MAY* include it's current position in its output and the raymarine plotter *MAY* detect it from that stream.

 

[pvb]

Or disconnect the GPS from the Raymarine plotter and connect it to the radio.

If the AIS has its own GPS then it *MAY* include it's current position in its output and the raymarine plotter *MAY* detect it from that stream.

It'd only have its own GPS if it's a transponder.

 

[ghostlymoron]

It is a transponder but I understand it gets it's position from the plotter.

 

[prv]

It is a transponder but I understand it gets it's position from the plotter.

I believe the rules for transponders require them to have their own dedicated GPS receiver.

Pete

 

[pvb]

I believe the rules for transponders require them to have their own dedicated GPS receiver.

Correct. Sounds like ghostlymoron's pal needs some professional advice!

 

[ghostlymoron]

So it just needs an aerial then.

 

[pvb]

So it just needs an aerial then.

No, if the boat has an AIS transponder, it should already have an additional GPS receiver (ie additional to the one connected to the plotter) which could be used to feed GPS data to the DSC radio.

 

[Elessar]

My pal has a raymarine plotter (large), icom radio and ais (unknown make). The position data is not shown on the dsc. Apparently the radio and ais need different baud rates and the plotter can't do both at the same time. Any solutions? He's planning to fit an additional gps dongle but that seems inelegant to me.

If the AIS is NASA and the GPS data comes from a "mushroom", feed the GPS to the VHF and the AIS (in parallel). Set the GPS to the 38400 BAUD so it can read the AIS, and the AIS will also feed out the GPS data at 38400. Other AIS units may have the same feature, I don't know.

If the GPS is internal to the raymarine then you are right you can't have a different BAUD rate for input (AIS, 38400) and output (GPS for the VHF, 4800) In which case dedicated mushroom for the GPS data to VHF is indeed needed. I used the Digital Yacht one, about 90 quid.

 

[ghostlymoron]

What's the difference between a transponder and a transceiver?

 

[pvb]

What's the difference between a transponder and a transceiver?

Both terms used for an AIS device which both receives and transmits AIS data. Technically, "transponder" is incorrect, but it's widely used so appears acceptable. If you have such a device, it's supposed to have an independent GPS source.

 

[Elessar]

What's the difference between a transponder and a transceiver?

strictly speaking a transponder is like a satellite or remote tv transmitter, it receives then retransmits the same thing.

It seems in the AIS world it means one that broadcasts your position (and other data) to others and receives others transmissions to display.

receiver only is c£100 where a receive and transmit is lots more.

 

[wooslehunter]

Try & get the model numbers of the equipment. Then we can try to work out a solution.

 

[nigelmercier]

Both terms used for an AIS device which both receives and transmits AIS data. Technically, "transponder" is incorrect, but it's widely used so appears acceptable. If you have such a device, it's supposed to have an independent GPS source.

Transponder is correct for Class A devices (they transmit having been given a slot), transceiver for Class B (they transmit randomly with no handshake).

 

[Elessar]

Transponder is correct for Class A devices (they transmit having been given a slot), transceiver for Class B (they transmit randomly with no handshake).

you are right - it has gained a second meaning that I hadn't realised.

"In telecommunication, a transponder is one of two types of devices. In air navigation or radio frequency identification, a transponder is a device that emits an identifying signal in response to an interrogating received signal. In a communications satellite, a transponder gathers signals over a range of uplink frequencies and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals.

The term is a portmanteau for Transmitter-responder. It is variously abbreviated as XPDR, XPNDR, TPDR or TP[1])"