Short in the antenna input - Garmin GPS/ Sonar

[w2much]

This message appears when I power up my unit. I turned the unit on in the AM and it acquired satellites as it it should. When I checked it a few hours later the message appeared."Short in antenna input" . Does this mean my antenna went bad ? Or something internal in the unit ? How often does an antenna go bad ?

 

[alldodge]

The signal isn't making it to the unit. The break/short can be the antenna, cable, connector or in the unit itself. Like all electronics things like this can happen due to a bad solder joint or from time and vibration. If your boat takes a lot of pounding it can takes it s toll over time. Is the antenna separate from the unit?

 

[dingbat]

antenna shorted to ground is usually due to a momentary conection between the unit and the antenna cable. Disconnect the antenna from the unit. Turn the power on without the antenna for a few moments, then turn the unit off. Reconnect cable and turn unit on. If mesage is still there the antenna needs to be replaced.

 

[Silvertip]

Check the connector carefully. Shorts can develop at the connector due to flexing or just a bad termination job. The connector can be replaced. Radio Shack is your friend for connectors.

 

[w2much]

The message does not appear when the antenna is disconnected. When connected the message appears. Are there some test which can be done with a multimeter?

 

[w2much]

I was lucky enough to find an adapter in my box of odd boat stuff that adapted the radio (VHF) antenna to the GPS type antenna fitting. I tried it out and picked up some weak satellite signal and the "Short" message did not appear. I will try to put a new end on the cable . Will post with the results.

 

[gm280]

Not sure what type antenna connection you have, but look at it closely to see if there is even a singel wire across the terminals. When they assembly some of those antenna connectors they some times don't get all the coaxial shields wire out of the assembly and just one little strand of shield wire will short it out. It could be a PL259 connector. That is used on lots of antenna setups.JMHO

 

[StingrayMike]

What type of antenna do you have and how is it connected to your plotter?
if it a NMEA 2000, most likely it will be the antenna, highly unlikely the ccable.
if it is a bnc, thst would be the 1st thing to check. You can hook up the multimeter aand do a continuity check end to end and see if it is shorted. If not you know its the antenna. If it is then look at the connections and cut off the one that looks bad, then do checks again.
you could also hook up an external cable from your garmin to the antenna, that will also tell you if its the cable or antenna

 

[w2much]

This unit has an external antenna. The garmin antenna I believe is a GA 29. I have not opened the unit but it appears to be hard wired into the antenna with the GPS end a BNC connecter. The unit was working for a few hours then came the error message. The boat was not moving it was on my driveway so that shaking or vibration was not a contributing factor.I did a continuity test at the BNC connector it did not show a short. The unit and antenna have been installed for many years pretty much untouched.

 

[alldodge]

Don't know if its worth a try, but if its in the antenna you could try another one. There are many GPS antennas out there under $15. Most use SMA connectors but they do make SMA female to BNC male

 

[dingbat]

Long duration shorts are typically heat related. Could be a coil heating up, weak resistor, etc. GPS antennas can and do go bad over time. Replaced the GA 29 on my 182 on the last boat.

 

[StingrayMike]

AllDodge and Dingbat both make very good and accurate points. Antennas go bad, and that one doesn't seem to be to expensive to buy new and replace.
if its not it, then you have a new spare/ backup when needed.

 

[w2much]

I am going to purchase a new one. I see them on ebay for as little as 32.00. ,from China. They have the Garmin name on them. I just hope they are indeed Garmin. Anybody know where these Garmin antennas are made?

 

[w2much]

Does the cable length matter ? I do not need 20 feet of cable. Has anyone purchased one of the Chinese models.?

 

[alldodge]

Dingbat is the expert but most all the antennas are made in Asia. There is signal loss with all cables but I don't think it will bother your reception. If it was mine I would try one of the cheapest ones and not worry if it has Garmin on it.

 

[dingbat]

Does the cable length matter ? I do not need 20 feet of cable. Has anyone purchased one of the Chinese models.?

Cable length doesn't matter. I've shortened every one I've ever owned.

A lot, if not all of the GA29 antennas where made in Taiwan for Garmin.