GPS (Etrex) Connection to VHF (Cobra F55)

[Phil_A]

Hi,

I'm trying to connect a Garmin Etrex to a Cobra F55 VHF DSC. Having looked at the instruction manuals for both units and various posts on this forum I have the NMEA out from the garmin connected to the red wire on the Cobra and the black wire on the cobra connected to the negative on the garmin which is also hooked up to the boat negative.

The Etrex is set to NMEA out (0183 Ver 3) with a baud rate of 4800 however, the Cobra refuses to accept any data communication from the Etrex. I have upgraded the Etrex firmware to V2.14, the latest for that model and have confirmed the NMEA output by connecting to a PC:

$PGRMZ,69,f,3*24
$GPRTE,1,1,c,*37
$GPRMC,173302,V,5128.0657,N,00310.2294,W,20.0,0.0,230607,3.8,W,S*26
$GPRMB,V,,,,,,,,,,,,A,S*0E
$GPGGA,173302,5128.0657,N,00310.2294,W,8,09,2.0,20.9,M,50.7,M,,*6A
$GPGSA,A,3,05,09,12,14,17,18,22,26,30,,,,,2.0,3.0*1F
$GPGSV,3,1,09,05,46,232,47,09,77,087,51,12,63,221,49,14,25,314,43*7E
$GPGSV,3,2,09,17,25,046,43,18,18,238,40,22,25,275,43,26,13,153,39*73
$GPGSV,3,3,09,30,28,232,43*4D
$GPGLL,5128.0657,N,00310.2294,W,173302,V,S*51
$GPBOD,,T,,M,,*47
$PGRME,15.0,M,22.5,M,15.0,M*1B
$PGRMZ,69,f,3*24

I have also confirmed with a volt meter that there is a voltage pulse every 1sec between the red and black wires of the data cable going to the back of the Cobra radio.

I have also tried changing the wire connections through every other combination just in case I'd got it connected incorrectly. I have even tried changing the Lat Lon format on the Etrex (mins sec to min dec) although I understand that wont change the NMEA data output. I have searched this site and although there are posts about Cobra F55 and Etrex, I’ve not found any with the same problem. I've now run out of ideas so any advice would be very welcome. Thanks

Regards

Phil

 

[hightech]

Assuming you have etrex white wire to the red of the cobra and the blacks of both together, then there is no reason why it should not just lock on.

Some VHF will not show much until your MMSI is loaded in, is yours? Not sure about the cobra though.

 

[CPD]

This is the setup I have and had no probs at all getting it to work using wiring diags supplied. Also cobra doesnt need mmsi to show lat/long.

 

[Phil_A]

Hi,

Yep, the Cobra has my MMSI entered. The cobra website states it needs NMEA RMC which the Etrex does not have a setting for but the NMEA output does include the $GPRMC tag so I assume that would be correct. I have emailed Cobra for advice as I'm beggining to wonder if there is a compatibility issue with the older etrex version that I have.

Rgds

Phil