GPS antenna

[petrolhead63]

I have been fitting many "new"electronics to our cruiser and it has taken a long time feeding cables/wires etc from radar arch, flybridge, to lower helm, saloon etc. I had extreme difficulty pulling the gps antenna cable down the arch and all the way to the lower helm where the main unit is. It has one of the very thin coax cable with a teeny sma plug on it, not the strong thick 8mm TV type.
I am having trouble with the unit, sometimes it works fine and others it just will not get a fix. I wonder if I broke the cable internally and it makes/breaks contact or is relying upon a length of wire as an antenna!

The cable is moulded into the antenna so it is not easy testing it....I thought to plug a new antenna in and see what happens is easiest quick test.
Does anybody know if I could use one of the little inexpensive antenna made for a car on the standard horizon plotter? or are these amplified and need a power source?

 

[Plum]

I have been fitting many "new"electronics to our cruiser and it has taken a long time feeding cables/wires etc from radar arch, flybridge, to lower helm, saloon etc. I had extreme difficulty pulling the gps antenna cable down the arch and all the way to the lower helm where the main unit is. It has one of the very thin coax cable with a teeny sma plug on it, not the strong thick 8mm TV type.
I am having trouble with the unit, sometimes it works fine and others it just will not get a fix. I wonder if I broke the cable internally and it makes/breaks contact or is relying upon a length of wire as an antenna!

The cable is moulded into the antenna so it is not easy testing it....I thought to plug a new antenna in and see what happens is easiest quick test.
Does anybody know if I could use one of the little inexpensive antenna made for a car on the standard horizon plotter? or are these amplified and need a power source?

If the cable is just/only a coax then there is no power source and no electronics in the antenna so worth trying and gps aerial to see of you get a consistant signal.

Www.solocoastalsailing.co.uk

 

[petrolhead63]

well an sma plug has only two connections, being the core and the braided sheath.....that said i have come across antenna with power in the coaxial cable with the signal..including sky cabling! Car ones with a sma plug on them I now see say thye are 3-5V which I assume is powered in the coax from the head unit.
I therefore need to see if the standard horizon plotter powers its antenna?

 

[CLB]

You put "new" in inverted commas. Is this because they are new to you, and in reality used? If so, there could be a problem with the antenna. Some have a battery inside that could be failing.

 

[petrolhead63]

hi, correct, new old unused in box....it worked fine sat at home on bench test. I never knew some had batteries in the antenna! I am not sure the manual would tell me much but will look. It is odd, cruised a day to IOW recently and it worked all day.
Saturday, nothing all day...no fix, date or time update remaind dated as last time on.

 

[jrudge]

The raymarine ones have a small button cell in them.

They are not in the manual and in theory last for some 10 years. Then you can as a DIY exercise open the unit and change it.

You could have damaged the wire- but damaging it to the extent that it works sometimes and not others I would think it relatively remote.

The kit is new to you and at the risk of being obvious there are two ends to the this - the GPS and the plotter. The GPS is not usually an aerial but a receiver in its own right that then sends the position over the wires in whatever format.

The most practical thing I suspect is to buy another, rig it into the flybridge helm ( often they are placed there anyway) and see if it works. If not then stick it on ebay and you know its the plotter.

I assume you have checked the obvious things like connections, and that the unit is getting enough voltage.

You dont say the brand but Raymarine and Garmin ( and I would imagine most others) allow you so see the GPS signal details on screen which may give you some idea. They also allow restart in software which can bring it back to life.

 

[vas]

agree with all previous posters, but to add another aspect of it all, how about putting the GPS antenna under the sundeck (assuming a f/b boat)?
I have my Garmin antenna there for the last 3yrs and it has performed brilliantly, no probs whatsoever feeding to a v. extensive NMEA2000 network with two plotters and 3 4inch multifunction displays!
And most important no need to route cables to radar arch just remove a ceiling panel (if it's easy) or route it via cabinets, etc

give us brands of equipment and I'm sure ppl will be able to help. And as jrudge says, try the plotter skyview screen with the satelites that are locked to the unit and accuracy details, and go from there.

cheers

V.