Jeff wrote:
The vast majority of small craft do not carry radar, but do have vhf
and gps; so I can see that the addition of a cheap AIS receiver would
complement the system very well.

Shipplotter works very well.
www.shipplotter.com

JK escreveu:
Jeff wrote:
The vast majority of small craft do not carry radar, but do have
vhf
and gps; so I can see that the addition of a cheap AIS receiver
would
complement the system very well.

Shipplotter works very well.
www.shipplotter.com


I agree with you 100%. After reading the several information about AIS,
including the already available hardware (cheap AIS receivers) and
softwares (including several very cheap and/or free) I am thinking that
the recently introduced DSC function of the newest Garmin marine gps
models like the Map276C/Map3006/Map3010 will be or are already totally
obsoleted, because AIS is and will be the standard, as it is many more
times usefull. I hope Garmin wakeup fast to change that obsolete DSC
function in a more advanced and usefull AIS function, in these gps
models.

" I agree with you 100%. After reading the several information about AIS,
including the already available hardware (cheap AIS receivers) and
softwares (including several very cheap and/or free) I am thinking that
the recently introduced DSC function of the newest Garmin marine gps
models like the Map276C/Map3006/Map3010 will be or are already totally
obsoleted, because AIS is and will be the standard, as it is many more
times usefull. I hope Garmin wakeup fast to change that obsolete DSC
function in a more advanced and usefull AIS function, in these gps
models.


DSC will not be obsolete, it performs a completely different function to
AIS; that of alerting other stations of DISTRESS and calling specific
stations. Routine position reports are not sent by DSC, its name, Digital
selective Calling really says it all.

As far as being obsolete on gps receivers; would you not like the position
of a vessel in distress shown on your electronic chart?

Adding the position of vessels transmitting AIS positions would be a huge
advantage, but really you need both functions.

I doubt if AIS will ever replace DSC for calling distress working, those
functions are not included in the protocol, and the channel occupancy can be
too high for reliable distress working; not to mention that DSC is used not
only on VHF, but MF and HF as well.


Regards
Jeff

On Wed, 11 May 2005 08:40:34 +0100, "Jeff" wrote:

I doubt if AIS will ever replace DSC for calling distress working, those
functions are not included in the protocol, and the channel occupancy can be
too high for reliable distress working

It's a pity though - to have distress transmissions included in AIS would be
very useful would only require another message number to be added (although
it would mean a hell of a lot of firmware upgrades around the world!)

Is channel occupancy really that much of a problem? I've been looking at data
from around some of the busiest shipping lanes in the world, and there still
seems to be plenty of capacity.

Dave

The email address used for sending these postings is not valid.
All replies to the group please.

Ok Jeff,
I agree that the distress function of the RADIO using DSC is important,
but for this, any gps can send the position of my boat to the radio, so
that the mayday buttom works. I was saying that the polling function of
the radio, for position report on my gpsmap276c is much less usefull
than a AIS function. The position report can tell me the position of
others boat only when ruested by the polling function, so I must know
the mssi code of the boat; I think this can be usefull to a flotilla
cruising or maybe to fishing boats, or a race comitee. To have the
position of a mayday boat in the gps ploter is not so usefull, because
it is rare fact, and a sailboat or any leisure boat has little to do an
a mayday function, contrary to ships or CG duties. The AIS main value
from a sailboat perspective is Colision avoidance, and in this regard,
a AIS transponder with a AIS receiver would be better, but a AIS
receiver only would be vey usefull .

Concluding, I think that the ideal solution would be a VHF/DSC/AIS
ready radio, wich could receive the AIS signal of all ships for
colision avoidance using litlle 12 V charge, but in a danger situation,
I could activate the transmit function to send automactic to all ships
my position (uses more 12V). The AIS NMEA message received could be
send to my Gps/Ploter wich would plots the ships position etc, like
others softwares does (ShipPloting, SeaClear, MaxSea, SeaPro etc), and
providing other important information like CPA/TCPA etc.

Regards

Pascal

"Pascal" wrote in message
oups.com...
Ok Jeff,
I agree that the distress function of the RADIO using DSC is important,
but for this, any gps can send the position of my boat to the radio, so
that the mayday buttom works. I was saying that the polling function of
the radio, for position report on my gpsmap276c is much less usefull
than a AIS function. The position report can tell me the position of
others boat only when ruested by the polling function, so I must know
the mssi code of the boat; I think this can be usefull to a flotilla
cruising or maybe to fishing boats, or a race comitee. To have the
position of a mayday boat in the gps ploter is not so usefull, because
it is rare fact, and a sailboat or any leisure boat has little to do an
a mayday function, contrary to ships or CG duties. The AIS main value
from a sailboat perspective is Colision avoidance, and in this regard,
a AIS transponder with a AIS receiver would be better, but a AIS
receiver only would be vey usefull .

Concluding, I think that the ideal solution would be a VHF/DSC/AIS
ready radio, wich could receive the AIS signal of all ships for
colision avoidance using litlle 12 V charge, but in a danger situation,
I could activate the transmit function to send automactic to all ships
my position (uses more 12V). The AIS NMEA message received could be
send to my Gps/Ploter wich would plots the ships position etc, like
others softwares does (ShipPloting, SeaClear, MaxSea, SeaPro etc), and
providing other important information like CPA/TCPA etc.

Regards

Pascal

IMO will not allow AIS and ARPA on the same screen, so some larger
commercial radar displays now are on the market with a switch to toggle
between ARPA and AIS. These same units sometimes are sometimes available for
non-IMO vessels allowing simultaneous ARPA and AIS on the screen. Adding DSC
on the same screen would probably not be a smart idea due to clutter.
Putting it on a separate chart plotter that polls the DSC VHF and HF radios
sounds better to me.
73
Doug K7ABX