Most of the recreational radios scan 70 most all the time, so if there's
anybody within range with a recent radio, DSC is going to get their
attention.

And if you are out of range of VHF, you're out of range, DSC or not.

The selective calling thing works, though ICOM's human factors to use it
suck. SH's human factor are great -- both radios get set to the working
channel, ring like a telephone, pick up the mike and talk. That's it.


"Larry" wrote in message ...
"RB" wrote in newsl5Lf.25391$Ly6.24795
@bignews5.bellsouth.net:

What is the DSC term used with marine VHFs?



A half-assed, 1980's digital technology invented to call one ship from
another so shipping companies can eliminate the expensive crew position of
radio officer the unions used to force upon them with government
intervention. It was poorly planned, draggedly implemented causing its
effectiveness to be very poor in emergency conditions.

The attempts to implement it in yacht transcievers with only a one-push-
button emergency mode plus a one-at-a-time selective calling feature is
nearly useless as the radios only switch to Channel 16 for FM voice if
someone within the 10-15 miles of VHF range happens to be listening to
DSC's channel 70, which only the ships are, forced by international law to
do so.

If you're "out there" and cannot see a ship on the horizon and are further
than 20 miles at sea, noone will hear the call....so don't think DSC is
going to save you any more than channel 16 is under these conditions. Buy
a 406 Mhz EPIRB with a GPS receiver in it and properly register it.
"They" are listening to it because "they" are using it to save their own
asses. http://www.noaanews.noaa.gov/stories/s1199.htm

"Pascal" wrote in message
oups.com...
Thank You very much. I know the diference betwen the two (DSC and AIS)
, but I am not concerned with distress comunications with others ships
or coast guards, but am looking for AIS to get the ships information to
avoid any potential colision danger and for fun in the sea. Praticaly,
here in Brazil, DSC do not exist, and here the so called Coast Guard
does not exist either, only a very few of the navy ships and some
airplanes (all obsoletes, without AIS) do to surveilance os the imense
brasilian coast (about 3,000 nm), so a mayday in the sea is almost a
null attempt.

"DSC and AIS use almost exactly the same digital
modulation/demodulation
technology so the R&D money spend on either system to adapt existing
analog
radio designs to digital modulation benefits the other"

Exactly, why do not include (combine) an AIS Modem (Chanel 87/88) and
the AIS software into the recent launched Standard Horizon
CVP350VHF/DSC radio/plotter, for example?

Regards

Pascal


I couldn't find information concerning a standard horizon model cpv350
anywhere on the net. I suspect that the problem is the display firmware.
Manufacturers such as standard horizon already make GPS chart plotters that
can handle one or a few waypoints from a DSC receiver but I suspect that
their firmware in the display cannot handle the hundreds of complex
waypoints that would come flooding in from an AIS decoder. The display
firmware will need to be significantly enhanced to show not only lat and lon
but the direction the ship is pointing and the speed of the ship.

It's CPV350, not CVP350.

http://www.standardhorizon.com/index...3&isArchived=0

I found it no sweat on SH's website.

"Ted" wrote in message .net...

"Pascal" wrote in message oups.com...
Thank You very much. I know the diference betwen the two (DSC and AIS)
, but I am not concerned with distress comunications with others ships
or coast guards, but am looking for AIS to get the ships information to
avoid any potential colision danger and for fun in the sea. Praticaly,
here in Brazil, DSC do not exist, and here the so called Coast Guard
does not exist either, only a very few of the navy ships and some
airplanes (all obsoletes, without AIS) do to surveilance os the imense
brasilian coast (about 3,000 nm), so a mayday in the sea is almost a
null attempt.

"DSC and AIS use almost exactly the same digital
modulation/demodulation
technology so the R&D money spend on either system to adapt existing
analog
radio designs to digital modulation benefits the other"

Exactly, why do not include (combine) an AIS Modem (Chanel 87/88) and
the AIS software into the recent launched Standard Horizon
CVP350VHF/DSC radio/plotter, for example?

Regards

Pascal


I couldn't find information concerning a standard horizon model cpv350 anywhere on the net. I suspect that the problem is the
display firmware. Manufacturers such as standard horizon already make GPS chart plotters that can handle one or a few waypoints
from a DSC receiver but I suspect that their firmware in the display cannot handle the hundreds of complex waypoints that would
come flooding in from an AIS decoder. The display firmware will need to be significantly enhanced to show not only lat and lon but
the direction the ship is pointing and the speed of the ship.

"Larry" wrote in message
...
"Ted" wrote in
. net:

When the two systems are merged
the AIS display will let you pick the ship you want to talk to and
call only him using DSC. Everyone else will not have to listen to
your conversation.


That's true if you stay on Channel 70 and don't listen to 16 or the other
CB channels...68, 69, 71, 72, 10, 12, 13....(c;


I'm not sure why they dont implement DSC on all VHF marine channels. Maybe
they will in the future after it is proven on channel 70. Do the current
DSC capable radios allow you to use DSC on channels other than 70??

On Sat, 25 Feb 2006 02:23:31 GMT, "ted" wrote:

I'm not sure why they dont implement DSC on all VHF marine channels. Maybe
they will in the future after it is proven on channel 70.

You miss the point. Channel 70 is the calling channel for DSC, not
the working channel, just as channel 16 is the calling channel for
voice.

And Larry seems to think that radio has to be tuned to 70 to receive DSC calls.
It doesn't. It scans 70, as nearly as I can tell, no matter what you do. It least my
SH Spectrum does, as does a buddy's more recent SH, and another buddy's
Icom.


"ted" wrote in message news

"Larry" wrote in message ...
"Ted" wrote in
. net:

When the two systems are merged
the AIS display will let you pick the ship you want to talk to and
call only him using DSC. Everyone else will not have to listen to
your conversation.


That's true if you stay on Channel 70 and don't listen to 16 or the other
CB channels...68, 69, 71, 72, 10, 12, 13....(c;


I'm not sure why they dont implement DSC on all VHF marine channels. Maybe they will in the future after it is proven on channel
70. Do the current DSC capable radios allow you to use DSC on channels other than 70??

"Wayne.B" wrote in message
...
On Sat, 25 Feb 2006 02:23:31 GMT, "ted" wrote:

I'm not sure why they dont implement DSC on all VHF marine channels.
Maybe
they will in the future after it is proven on channel 70.

You miss the point. Channel 70 is the calling channel for DSC, not
the working channel, just as channel 16 is the calling channel for
voice.


Perhaps I did miss something here. Are you saying that there is never any
voice on channel 70, but only a digital data exchange and then both ships
radio's change freqency to a working channel? Who decides which working
channel to switch to? Does the radio check to make sure the channel is not
in use first? I assume that the voice communication on the working channel
is analog and can be heard by traditional radio equipment?

There is never any voice on 70, only data, at least in theory. DSC radios
won't let you do voice on 70. Dunno about older radios. For the emergency
button, 16 is working channel. For individual calls, the calling human sets the working
channel prior to the call. The radio does not check that the working channel is free.
It's normal analog voice comms on the working channel.


"Ted" wrote in message ink.net...

"Wayne.B" wrote in message ...
On Sat, 25 Feb 2006 02:23:31 GMT, "ted" wrote:

I'm not sure why they dont implement DSC on all VHF marine channels. Maybe
they will in the future after it is proven on channel 70.

You miss the point. Channel 70 is the calling channel for DSC, not
the working channel, just as channel 16 is the calling channel for
voice.


Perhaps I did miss something here. Are you saying that there is never any voice on channel 70, but only a digital data exchange
and then both ships radio's change freqency to a working channel? Who decides which working channel to switch to? Does the radio
check to make sure the channel is not in use first? I assume that the voice communication on the working channel is analog and can
be heard by traditional radio equipment?

On Fri, 24 Feb 2006 21:01:32 -0800, "Chuck Tribolet"
wrote:

And Larry seems to think that radio has to be tuned to 70 to receive DSC calls.
It doesn't. It scans 70, as nearly as I can tell, no matter what you do. It least my
SH Spectrum does, as does a buddy's more recent SH, and another buddy's
Icom.


The SC-101 class radios allow the user to disable the channel 70 scan,
effectively disabling DSC reception. My brother-in-law's new Icom 502
came set that way - confused us when I tried some DSC tests with him -
his older, cheaper Icom could receive my calls regardless of the
selected channel, but the new expensive unit had to be set to 70. (He
discovered this setting while reading the book later in the day, after
we'd left our boats - we assume that DSC reception will work as
expected once he enables the Ch70 scan)


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

In article ,
"Chuck Tribolet" wrote:

And Larry seems to think that radio has to be tuned to 70 to receive DSC
calls.
It doesn't. It scans 70, as nearly as I can tell, no matter what you do. It
least my
SH Spectrum does, as does a buddy's more recent SH, and another buddy's
Icom.


I think that you should qualify your above statement, a bit. You should
state that, "Your radio receiver scans VHF Marine Ch 70 while it is not
transmitting, and you think your buddies radios do as well". There are
a lot of DSC Equiped radios that may or may not, scan VHF Marine Ch 70,
or may or may not have a dedicated Ch 70 Receiver builtin. Just how
each model radio's Scan Routine is implimented by the OEM is propritary,
and problematic, to how it responds to a DSC Signal. There are some
radios that don't receive on CH 70, while the receiver is receiving a
signal on the programed channel, and some that don't recieve on Ch 70
while the radio is on Ch 16.
DSC in the Western Hemisphere is still mostly under implimented, and
untill the USCG, and other Governmental Entities, catch up with their
European Counterparts, the OEM's aren't really going to get the Consumer
Type Radios up to dealing with DSC with a full implimentation.

Bruce in alaska
--
add a 2 before @