GPS to ICOM VHF-arghh!#@*

sbrockman

sbrockman

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Have just installed an ICOM M601 but am having problems getting a GPS to talk to it and display a position. Have tried connecting a Lowrance 3500c and a Garmin152 but still get no position displayed on the vhf. Both units are set for nmea out, I've tried adjusting the baud rate but to no avail. The M601 says it accepts the NMEA versions that these two units output. I contacted ICOM who told me the vhf is merely a repeater and I should contact Lowrance /Garmin.

Any ideas what the problem might be? - I'm kind of stuck

Thanks in advance

Steve B
 
I have a Garmin 152 and Icom M421, yet to be wired up. I did a search recently in anticipation and came across a couple of posts on the web (possibly from this site, I dont recall)..... I've pasted them below in case they help any (presumably the Icoms will be similar). hope it helps. If you get it installed ok, please post back on any tips as I'll likely be tackling this myself in a few weeks time!!


*************** Snipped from web posts ****************

Answer from web post: I had the same question and asked the Tech support people at Icom. "The M402 has an "RCA" style in jack on the back for connecting the GPS. You will need to aquire an RCA male connector and wire the NMEA out from the GPS (usually blue on Garmin) to the center pin. Connect the NMEA ground (usually black, shared with power on Garmin) to the outer ring."

Answer from another web post:
Your GPS has two NMEA channels, COM 1 and COM 2.
Radio Yellow (NMEA IN +) to GPS Blue (NMEA OUT COM 1 Tx)
Radio Green (NMEA IN -) to GPS black (Ground)OR
Radio Yellow (NMEA IN +) to GPS Green (NMEA OUT COM 2 Tx)
Radio Green (NMEA IN -) to GPS black (Ground)
Then setup the right comms format:
Main Menu
Comm
Select Port 1 (aka COM 1) or Port 2 (aka COM 2)
Transfer Mode NMEA In/Out
Speed 4800.
That SHOULD do it. There's some stuff in the advanced setup
where you could shoot yourself in the foot, but just leave
it alone.
Whether to use COM 1 or COM 2.
COM 1 is the only one that can be used for hooking your
computer up to do downloads.
COM 2 is the only one that can do DGPS.
Either can take the radio. Since DGPS is as rare these days
as hens teeth, I'd connect using COM 2.
 
this really should be easy Steve............

[ QUOTE ]
Both units are set for nmea out

[/ QUOTE ] worries me - the radion should be nmea in - maybe yuou menat that you had set both GPS to out when trying.

I will get both manuals out and detail it

ICOM units usually come with the jack to NMEA / speaker etc in as part of the kit - you need to connect the wires from this jack as per the manual to the gps feed

manuals next door - brb
 
right - using the Lowrance unit it's the yellow wire to the ICOM nmea +ve data in and the sheild wireing to the NMEA - ve in

menu menu system setup enter to configure com port

radio button nmea 0183 out (bottom one)

baud 4800 fine

radio's default should take this straight away


hope this helps
 
I'm not familiar with the actual units you are talking about but have just been connecting my Garmin handheld to a Furuno Navtex. I didn't have any problems, except that the date/time fields on the Navtex data display were blank and after checking the sentences ouput by the GPS I found that the date/time sentence is not output from the Garmin72.

So, I can provide some general information which may help:

GPS "NMEA OUT" should be connected to Radio "NMEA IN"; this is NMEA "+" to NMEA "+" and "- or ground" to "- or ground"

The data settings should be: 4800 baud (bits per second)
8 bits
1 stop bit
no parity
no flow control

I think most GPS will output the relevant sentence for position data "GPGLL" and "GPGGA" as default settings, plus other sentences that are not so important or which may not be read by the radio.

If you have any specific questions then please PM me and I'll try and help.

Alan.
 
Many thanks to everyone for their helpful replies, some of which I have tried - the others I will try tomorrow - will keep you informed.

Thanks again

Steve B
 
I did my 421 recently and it was straignt forward, i don't have the wiring details to hand as they're on the boat but I didn't have to input the mmsi No. to get it to display position, is that just for the 601 unit?
 
I return - somewhat shame-faced, the problem resolved. When connecting the Garmin 152 to the ICOM vhf I had only connected the Blue NMEA out from the Garmin to the vhf -ve this setup had previously worked on the NASA vhf. I hadn't realised that the black Garmin -ve wire was also the NMEA -ve output. It now all works fine.

I have to say yesterday was not one of my best days - on locking up the boat I realised I'd locked the keys inside, including the keys to get out of the marina! I was the only person there. Peterhead Marina is next to Peterhead Prison- I think the same contractors were responsible for the security arrangements!! there is no way out without a key apart from swimming for it - a bit like Alcatraz. An embarrassing call to the Harbour control room and I was soon released.

Thanks to all for their help.

Steve B
 
Thanks to this thread I have overcome similar problems...

The wiring diag in the destruction book for my Garmin 178 shows blue & black to 'Autopilot/NMEA Device' then green & black to 'Beacon receiver or DSC VHF' so being a dipstick at this sort of stuff I couldnt understand why - taking the book at its word - wiring my DSC VHF to green did nothing at all... /forums/images/graemlins/blush.gif

I now have some subtle appreciation - though I would say somewhat short of full knowledge - of what an NMEA device is... /forums/images/graemlins/crazy.gif

The VHF (Icom 421) book could be a little more helpful methinks??
 
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