Garmin etrex/ dsc vhf

[PhilF]

Help please if possible
I have a dsc vhf that has a positive and negative cable for reading GPS data.
I connected the neg to ground from the data cable out of the etrex and the pos to send data from the etrex.
sometimes the vhf reads the position as soon as the radio is turned on. sometimes it doesnt.
Sometimes the position is displayed on the vhf and sometimes is says "no gps signal". The wires are connected okay and the etrex never loses the postion.
the etrex is set for nmea out and there is no setting to change on the vhs.
is the etrex capable of this usage, I have no problems when I link it to my ipac for navigation purposes with the same cable.
Strange but true
PhilF

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[simonwood]

Hi,

1. What version of NMEA are you using?
2. In what order to you turn on your gps/dsc-vhf?

simon.

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[insider]

Philf , this is indeed odd given the ipaq experience, if you have a digital test meter set it to dc 20 volts ,positive to data positive ,neg to neg and watch the voltage, it will fluctate as the NMEA sentances changes but what is important is what happens when the radio "loses position".
If the voltage drops to zero or remains static or lower than the norm when the transmission is ok the Etex is at fault ,if the voltage reading are ok then the radio is at fault.
if you suspect the etrex check the connections on the back of the etex and see what is happening.
let me know what you find.

logical progression is a fault finding tool in every tool box
regards
insider

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by insider on 28/06/2004 22:06 (server time).</FONT></P>

 

[PhilF]

0183 version 3
I have tried turning the units on and off and re booting alternately, but there is no patern to the problem. happens when gps is first on or vhf is first on.. It cant be the connections to the etrex cause no prob with the Ipac, and the connections at the other end are bare wires. I cut the data cable and isolated the correct wires.

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[insider]

thats why you need to check the signal to see where is the fault , you only have 3 components, you did mention the radio brand , although they are all pretty reliable
these days, but I bet i know which brand it is given the fault.

insider

<hr width=100% size=1>Logical progression is fault finding tool in every tool box.
Regards,
Insider

 

[SpottedBlue]

I bet its an XM

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[PhilF]

Its in Spain and is a Hurricane DSC class D,, will do the digital test at the weekend, I have the etrex and cables in UK.
Thanks
Philf

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[Jools_of_Top_Cat]

I am going to guess from your description,

sometimes the vhf reads the position as soon as the radio is turned on

The radio reads the first sentence from the gps then misses all the others, I think the baud rate from your GPS may be too high. If your radio, which it prolly is, is set to 4800baud, anything faster will just be a blur to its on-board processor.

Check you have not set the etrex to output 9600baud or something, it needs to be 4800. I know this is a problem I had getting my radar to read the gps when I first set it up, like you it would get the odd one, and then nothing.......


hope this helps

<hr width=100% size=1>Julian

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[PhilF]

nope, set at 4800, its the only choice on the etrex with nmea out setting
more, more
Phil

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[PhilF]

I have looked at the XM and it is suspiciously similiar to the one I have. Is there an issue here that you could share?

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[SpottedBlue]

I had an XM DSC radio as an emergency replacement for a Navico that got hit by lightning and had exactly the problems you describe, called XM for advice and after getting passed backwards & forwards by some real idiots who treated me with contempt I got the usual run around - poor connection, bad signal etc etc.

I knew my NMEA position data source was ok because it was working fine with other devices, but despite this they were not interested in the problem.

Replaced the XM radio with an Icom 710 using the same NMEA data cable - it worked fine and since that day have never had any problems.

Draw your own conclusions!!

PS I would never buy anything else from XM

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