RM 9616I-LM Antenna

[patchelect]

I have a RM 9616T-LM GPS that seems to not like its antenna. Since acquiring it well over a year ago it will constantly lose its signal, searching until it finds one and then it often goes through the same searching shortly afterward. Sometimes it will work flawlessly. My location seems to have nothing to do with it. The antenna wire is the one paralleled to the power cord I am assuming. I split the two and laid it out closer to the unit mounted on the windshield. The GPS shows the same issues no matter what vehicle I am driving and in vehicles that my Magellan 3045LM works perfectly. I originally attributed it to overhead cover as I first used it on heavily treed roads but after a while I realized it did the same thing in open parking lots.

I've seen aftermarket antennas available and although I don't want to spend money for something the GPS is supposed to do normally I also can't see where it would plug in either, and I'm not confident that it will fix my problem anyway.

 

[Nuvi-Nebie]

The 'GPS' aerial is not part of the power cord, the unit functions with no power cord pugged in when the internal battery is sufficiently charged, so it can't use any external cabling as an antenna

The 9616 does not have a socket for an external antenna and can not use one

 

[patchelect]

Thanks for the antenna info. Any thoughts as to why I am constantly having signal problems? Is the built in unit that temperamental? I am in the colonies but that should have nothing to do with it!

 

[Nuvi-Nebie]

A GPS antenna is usually a ceramic square like this

It is typically 10 - 20 mm square and in this case is almost definitely positioned on the main printed circuit board inside the unit, it could be badly soldered to the main board, but I think that is unlikely unless the unit has been dropped, however there are other causes of GPSs failing, for example, the unit has an internal 'clock' that needs to be very accurate, if this clock is too far out the unit will have difficulty getting a satellite 'fix'

As you say, your position on earth shouldn't matter to the GPS, as every part of the globe is covered, although above 60 degrees North and South the signals are reduced, things that can effect a 'fix' are, things that get in the way such as tree cover, the metal in a car, buildings etc. so try it out of the car in an area with a clear view of the sky. If you find it it always works better when the temperature is above or below average, that might suggest a problem with it's internal clock, because it will vary with temperature

 

[patchelect]

The display clock seems to be spot on so I'll assume the internal clock is as well. I guess I'll have to try and get inside at look at the PC board. I guess I can also try hitting the unit when it is working properly and see if it effects a "searching for satellite" message showing the likelihood of a cold soldered joint.

 

[Nuvi-Nebie]

The display clock seems to be spot on so I'll assume the internal clock is as well.

You wont be able to see the error, we are not talking Seconds, we are talking micro / nano seconds, the unit has a quartz crystal (like in a watch), that drives the clock, but it needs to be within a few parts per million to work, as I said above the crystal is affected by temperature

 

[patchelect]

Okay, thanks