Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 17-08-2017, 17:41   #1
Registered User

Join Date: Nov 2009
Posts: 196
No GPS signal reaching M-802

When my Icom M-802 was installed it was connected into the boat's GPS system and it worked fine. At some point it stopped working and therefore the DSC will not be effective or not work at all. I want to fix this problem.

Can anyone tell me what the signal on the wires from the GPS should look like? This would help me track down the problem.

Or could some setting in the M-802 have been changed?

Any help would be appreciated.

FYI, I'm not an electronics guru so try and keep it simple.

Cheers.
mlibkind is offline   Reply With Quote
Old 17-08-2017, 18:13   #2
Registered User

Join Date: Dec 2016
Location: PNW
Boat: J/42
Posts: 938
Re: No GPS signal reaching M-802

What the wire looks like or what the signal looks like?
The cable has a BNC connector on one end and probably bare leads that tie into your GPS at the other.
The signal is NMEA 0183.
The only setting that I recall is "GPS detail" or something like, that controls how many digits are displayed.

The GPS unit might output at different speeds. The M802 needs "low speed" (4800 baud). If you at some point changed the baud rate to "high speed" (38400 baud) to match a new chart plotter or AIS or something, then it would be at the wrong speed for the radio. Just a guess.

Personally, I am getting vexing RF interference from the GPS, so I know too well what the signal sounds like.
toddster8 is offline   Reply With Quote
Old 17-08-2017, 19:56   #3
Registered User

Join Date: Mar 2007
Location: Santa Cruz
Boat: SAnta Cruz 27
Posts: 6,711
Re: No GPS signal reaching M-802

One of the reasons I hate Microsoft is because they removed the very helpful and free hypertext program from Windows after XP. It allowed you to monitor NMEA data on a laptop.

Unfortunately, the process is kind of geeky. You will need to disconnect the two NMEA input wires from the 802, connect them to pins 2 (+) & 5(-) of a nine pin serial cord, connect the serial plug into a serial/usb converter, load the drivers for the converter, find the right com port, then set the monitoring program (hpertext, Opencpn, gpsdiag,etc to the right baud rate (4800) and com port, and look at the data. If you see data, then work on the 802 settings. If you don't see data, check the settings for source GPS output.

If you feel like getting more geeky, hook a scope across the two wires and you will see little square waves dance across the screen if there is data flowing.
donradcliffe is offline   Reply With Quote
Old 17-08-2017, 21:31   #4
Registered User
 
Capt.Don's Avatar

Join Date: Aug 2010
Posts: 953
Images: 1
Re: No GPS signal reaching M-802

Quote:
Originally Posted by donradcliffe View Post
One of the reasons I hate Microsoft is because they removed the very helpful and free hypertext program from Windows after XP. It allowed you to monitor NMEA data on a laptop.
.....
putty works very well for monitoring serial feeds. Be sure to setup the COM port and baud rate correctly.

Don
Capt.Don is offline   Reply With Quote
Old 17-08-2017, 21:32   #5
Registered User
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 8,462
Re: No GPS signal reaching M-802

don, hypertext is available from MS as a free download.
DeepFrz is offline   Reply With Quote
Old 18-08-2017, 11:04   #6
Registered User

Join Date: Mar 2011
Location: fl- various marinas
Boat: morgan O/I 33' sloop
Posts: 1,447
Re: No GPS signal reaching M-802

Assuming your GPS is working on other devices it almost has to be a bad connection or a changed radio setting. Check the VHF manufacturer for how to set/change the GPS baud rate. Most systems use the low setting 4800. I don't think you need to read the signal on the wires to see if there is one causing current pulses.
Dave22q is offline   Reply With Quote
Reply

Tags
gps

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
ICOM M 802 SSB Install Part 2: GPS connection muttskie Marine Electronics 26 10-04-2019 19:24
Trouble getting GPS position to 802 lamadriver Marine Electronics 2 15-05-2016 08:50
Garmin GPS makes noise on Icon 802 Wainui Marine Electronics 0 28-01-2016 10:24
GPS Signal Interference in US CarlF Navigation 36 19-05-2012 08:13
GPS signal too weak on Datamarine 5000 phorvati Marine Electronics 2 11-08-2009 14:26

Advertise Here


All times are GMT -7. The time now is 17:19.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.