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Re: [PUP] AIS pitfalls

DC
Dave Cooper
Mon, Jun 4, 2007 11:11 PM

<John wrote: Actually, the FA-150 is a transponder... our buddies track us
via AIS when we are in the area long before they can raise us on VHF. Which
I find interesting given AIS uses VHF as well.>

Sorry I thought the FA-150 was just a receiver..my mistake.

The 3 GPS's in their 38' high location must have quite a ride ;-)

The reason they can see you when you can't reach them via VHF even though
you have 25 watts vs. the 4 of the transponder is due to the wonderful world
of digital transmission. It can get thru as it only looks for thresholds vs.
needing receive the full modulation of voice. Sort of like why Morse code
could always out do voice.

One of those GPS's must be dedicated to input the location, speed and
course...at least according to the spec. The other two are most likely the
differently pair to determine the ships heading.....hope you have a compass
as a back-up when it goes dark ;-)

So I must ask how you know what you are transmitting in all of the data
streams? Many of which most folks can't see...yet.

Have you received any Class B signals yet? Does your FA-150 have the
software to pick them up and display there complete data or does it leave
missing files without the word "missing".

You'd be a good guy to have around so I could talk to someone who can see me
and might actually be willing to talk back about the AIS. Not like the
Master of the Tropic Palm who basically "hung up" on me today. Bet we'd both
learn a lot more about each others units and what the ranges are :-)

And we haven't yet even got into the safety messages and DSC distress
messages it can deal with......a much more powerful tool than the current
VHF DSC, IMHO. It also has a much wider range due to the all digital nature.
So if you have a distress then instead of 10 or perhaps 15 mile radius you
have the radius of the AIS transponders signal...

Thanks for the correction :-)

As always YMMV

Cheers

Dave & Nancy
Swan Song
Roughwater 58
Caribbean Cruise '07

<John wrote: Actually, the FA-150 is a transponder... our buddies track us via AIS when we are in the area long before they can raise us on VHF. Which I find interesting given AIS uses VHF as well.> Sorry I thought the FA-150 was just a receiver..my mistake. The 3 GPS's in their 38' high location must have quite a ride ;-) The reason they can see you when you can't reach them via VHF even though you have 25 watts vs. the 4 of the transponder is due to the wonderful world of digital transmission. It can get thru as it only looks for thresholds vs. needing receive the full modulation of voice. Sort of like why Morse code could always out do voice. One of those GPS's must be dedicated to input the location, speed and course...at least according to the spec. The other two are most likely the differently pair to determine the ships heading.....hope you have a compass as a back-up when it goes dark ;-) So I must ask how you know what you are transmitting in all of the data streams? Many of which most folks can't see...yet. Have you received any Class B signals yet? Does your FA-150 have the software to pick them up and display there complete data or does it leave missing files without the word "missing". You'd be a good guy to have around so I could talk to someone who can see me and might actually be willing to talk back about the AIS. Not like the Master of the Tropic Palm who basically "hung up" on me today. Bet we'd both learn a lot more about each others units and what the ranges are :-) And we haven't yet even got into the safety messages and DSC distress messages it can deal with......a much more powerful tool than the current VHF DSC, IMHO. It also has a much wider range due to the all digital nature. So if you have a distress then instead of 10 or perhaps 15 mile radius you have the radius of the AIS transponders signal... Thanks for the correction :-) As always YMMV Cheers Dave & Nancy Swan Song Roughwater 58 Caribbean Cruise '07
JM
John Marshall
Tue, Jun 5, 2007 4:19 AM

Dave,
That really speaks the virtues of digital comm... lower power and
far longer range. It would be nice if Marine voice communications
would move away from FM and join the 21st century. We'd get vastly
better audio quality and apparently longer effective range.

To your sat compass question, we have a flux-gate compass in each of  

the two autopilots that can provide heading data on the bus if we
enable it. Plus a good old fashioned properly swung compass on the
dash in case something bright comes out of they sky. Fortunately
thunderstorms are rare as hen's teeth in the Northwest.

RE: what I'm transmitting. I can see what's being set for all the  

data streams in terms of manual input, but I don't have a way to
receive my own signal to ensure its right or that computed SOG, COG
or location is going out correctly. That's a weakness as you
highlighted at the beginning of this thread. I almost wish I could
call someone up for an "AIS check". Or spend the dollars for an AIS
receiver only, but not until they get a lot cheaper. I'm waiting for
the handheld variety to use as a "backup".

RE: Class B... I'm not sure if I've picked up any Class B signals or  

how I'd know... some boats report 0's for things like beam and length
and draft and so forth, but I've been assuming they simply haven't
set their system up properly.

RE: Messaging... Before I left Dana Point for the Northwest, an  

installation technician from Alcom transmitted a message to me via
AIS, but I never noticed it coming in. Once in port, I powered the
system down, only to have him come by and ask me if I'd gotten his
message. We powered the AIS back up and there was no message. Not
sure if it stores it in non-volatile memory or not. Have to play
further with this when I've got a buddy close by to work with, but
given that aspect is new (especially the emergency calling feature),
I think we're a bit ahead of the curve there.

Too bad I'm kittycorner across the US mainland from you or we could  

play. I know I'd learn a lot by exploring all the corners of AIS
capabilities.

John Marshall
N5520-Serendipity

On Jun 4, 2007, at 4:11 PM, Dave Cooper wrote:

<John wrote: Actually, the FA-150 is a transponder... our buddies
track us
via AIS when we are in the area long before they can raise us on
VHF. Which
I find interesting given AIS uses VHF as well.>

Sorry I thought the FA-150 was just a receiver..my mistake.

The 3 GPS's in their 38' high location must have quite a ride ;-)

The reason they can see you when you can't reach them via VHF even
though
you have 25 watts vs. the 4 of the transponder is due to the
wonderful world
of digital transmission. It can get thru as it only looks for
thresholds vs.
needing receive the full modulation of voice. Sort of like why
Morse code
could always out do voice.

One of those GPS's must be dedicated to input the location, speed and
course...at least according to the spec. The other two are most
likely the
differently pair to determine the ships heading.....hope you have a
compass
as a back-up when it goes dark ;-)

So I must ask how you know what you are transmitting in all of the
data
streams? Many of which most folks can't see...yet.

Have you received any Class B signals yet? Does your FA-150 have the
software to pick them up and display there complete data or does it
leave
missing files without the word "missing".

You'd be a good guy to have around so I could talk to someone who
can see me
and might actually be willing to talk back about the AIS. Not like the
Master of the Tropic Palm who basically "hung up" on me today. Bet
we'd both
learn a lot more about each others units and what the ranges are :-)

And we haven't yet even got into the safety messages and DSC distress
messages it can deal with......a much more powerful tool than the
current
VHF DSC, IMHO. It also has a much wider range due to the all
digital nature.
So if you have a distress then instead of 10 or perhaps 15 mile
radius you
have the radius of the AIS transponders signal...

Thanks for the correction :-)

As always YMMV

Cheers

Dave & Nancy
Swan Song
Roughwater 58
Caribbean Cruise '07


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Dave, That really speaks the virtues of digital comm... lower power and far longer range. It would be nice if Marine voice communications would move away from FM and join the 21st century. We'd get vastly better audio quality and apparently longer effective range. To your sat compass question, we have a flux-gate compass in each of the two autopilots that can provide heading data on the bus if we enable it. Plus a good old fashioned properly swung compass on the dash in case something bright comes out of they sky. Fortunately thunderstorms are rare as hen's teeth in the Northwest. RE: what I'm transmitting. I can see what's being set for all the data streams in terms of manual input, but I don't have a way to receive my own signal to ensure its right or that computed SOG, COG or location is going out correctly. That's a weakness as you highlighted at the beginning of this thread. I almost wish I could call someone up for an "AIS check". Or spend the dollars for an AIS receiver only, but not until they get a lot cheaper. I'm waiting for the handheld variety to use as a "backup". RE: Class B... I'm not sure if I've picked up any Class B signals or how I'd know... some boats report 0's for things like beam and length and draft and so forth, but I've been assuming they simply haven't set their system up properly. RE: Messaging... Before I left Dana Point for the Northwest, an installation technician from Alcom transmitted a message to me via AIS, but I never noticed it coming in. Once in port, I powered the system down, only to have him come by and ask me if I'd gotten his message. We powered the AIS back up and there was no message. Not sure if it stores it in non-volatile memory or not. Have to play further with this when I've got a buddy close by to work with, but given that aspect is new (especially the emergency calling feature), I think we're a bit ahead of the curve there. Too bad I'm kittycorner across the US mainland from you or we could play. I know I'd learn a lot by exploring all the corners of AIS capabilities. John Marshall N5520-Serendipity On Jun 4, 2007, at 4:11 PM, Dave Cooper wrote: > <John wrote: Actually, the FA-150 is a transponder... our buddies > track us > via AIS when we are in the area long before they can raise us on > VHF. Which > I find interesting given AIS uses VHF as well.> > > Sorry I thought the FA-150 was just a receiver..my mistake. > > The 3 GPS's in their 38' high location must have quite a ride ;-) > > The reason they can see you when you can't reach them via VHF even > though > you have 25 watts vs. the 4 of the transponder is due to the > wonderful world > of digital transmission. It can get thru as it only looks for > thresholds vs. > needing receive the full modulation of voice. Sort of like why > Morse code > could always out do voice. > > One of those GPS's must be dedicated to input the location, speed and > course...at least according to the spec. The other two are most > likely the > differently pair to determine the ships heading.....hope you have a > compass > as a back-up when it goes dark ;-) > > So I must ask how you know what you are transmitting in all of the > data > streams? Many of which most folks can't see...yet. > > Have you received any Class B signals yet? Does your FA-150 have the > software to pick them up and display there complete data or does it > leave > missing files without the word "missing". > > You'd be a good guy to have around so I could talk to someone who > can see me > and might actually be willing to talk back about the AIS. Not like the > Master of the Tropic Palm who basically "hung up" on me today. Bet > we'd both > learn a lot more about each others units and what the ranges are :-) > > And we haven't yet even got into the safety messages and DSC distress > messages it can deal with......a much more powerful tool than the > current > VHF DSC, IMHO. It also has a much wider range due to the all > digital nature. > So if you have a distress then instead of 10 or perhaps 15 mile > radius you > have the radius of the AIS transponders signal... > > Thanks for the correction :-) > > As always YMMV > > Cheers > > Dave & Nancy > Swan Song > Roughwater 58 > Caribbean Cruise '07 > _______________________________________________ > http://lists.samurai.com/mailman/listinfo/passagemaking-under-power > > To unsubscribe send email to > passagemaking-under-power-request@lists.samurai.com with the word > UNSUBSCRIBE and nothing else in the subject or body of the message. > > Passagemaking Under Power and PUP are trademarks of Water World > Productions, formerly known as Trawler World Productions.