(Gudguyham) wrote in
:
Hi fellas, I am a ham W1QJ and I am getting into APRS, I understand
how it works. My brother has a boat with a Garmin 2010 GPS unit and
an Icom VHF radio. Both of the manuals talk about DSC, but do not
tell you how to hook it up. I am assuming that it works similar to
the amatuer APRS. The lat. long. data gets fed from the GPS to the
VHF radio and then the radio can beacon the position of the boat. My
question is this. Which wires on the Garmin 2010 give out the data
that the VHF radio is looking for? The Icom VHF radio is looking for
"NEMA" data input, but when I called Garmin on the phone, they said
that the Garmin has their own data protocal. Is this a problem? If
so then what is the work around? Could anyone here that uses DSC and
understands it, please help me out. I am assuming that it is very
much like "connected packet"?? I may be wrong, but from what I read
about it, it sounds like it. Any help with a better understanding of
Marine DSC and help hooking up the Garmin to the Icom to get my
brother going on DSC would be appreciated. You can e-mail me direct
please. Or I can come back here for responses. Many thanks in advance
to anyone who can help me. 73 Louie W1QJ
Louis, hi. Larry, W4CSC, here. I was an APRS VHF node for years and even
helped WB4APR fix some Navy APRS transmitters on Academy yachts that ported
in Charleston get back online on the Navy system.
DSC doesn't "beacon" like APRS. It only transmits when you call someone's
MMSI unique number to digitally call them...or when you declare and
emergency by pressing the distress button for X seconds.
Look at the diagram of the installation manual:
http://www.garmin.com/manuals/47_GPS...lationGuide.pd
f
On diagram 2 note port 1 hooked to a computer's serial port and port 2
hooked to other devices (gray and violet wires of the cabling). Looks like
port 2 is the NMEA port, if you have NMEA data turned on.
http://www.garmin.com/manuals/41_OwnersManual.pdf
On page 76 of this owner's manual, you'll see the NMEA setup from the
Communications Tab of the main menu system. Looks like you'll need to turn
NMEA data on out of port 2 from this menu with the instructions provided.
That will get you NMEA data out and in on the gray and violet wires from
port 2. Garmin uses ground, damn them, instead of the balanced NMEA + and
- through an optoisolator so it will screw all your radios with serial data
noises. Sorry....
Just hook Port 2 output to the Icom's NMEA Input (A or +) and the Icom's
data output to the Garmin Port 2 input (A or +) wires. Ground the B or -
NMEA connections and you're in business....
You'll know you have NMEA data into the Icom because Lat/Long and the
correct time will show up on the Icom's display. I'm using Icom M802 HF
adn M602 VHF radios aboard Lionheart with great success. M602 is a
beautiful overkill of a VHF rig. The M502 is more practical but my captain
said the 602 matched the HF panel much better. Who am I to argue with the
captain's checkbook...(c;
73, Larry W4CSC
Chief Engineer
S/V Lionheart
WDB6254 MMSI 366920680
Buzz us on Channel 70 and we'll do lunch....(c;