GPS won’t/can’t acquire satellites

[Raymond]

At the Crawford Path parking lot on Wednesday, May 6, my GPS could not acquire satellites.

The GPS of course is a Garmin 60CSx. I have had trouble with it now and then previously, as some of you may remember, but I never saw anything like this.

It shows zero satellites on the display. None. No strength bars along the bottom of the display, either. Nothing but a little silver ball with a red dot on it, which moves a little bit around the compass circle, then settles in at the southeast position and stays there.

I removed the little memory chip under the batteries when I got home and tried a hard reset, pushing the Page and Enter buttons after turning it on. That reverted the display back to its default appearance, but did nothing to help it find satellites.

It also seems to think the time is something different from what the time actually is. Yesterday morning around ten o’clock, it thought it was 6:something p.m. It still does, although now it is more like 1 a.m.

I always save my tracks (active logs, etc.) to the memory chip, but nothing was established for May 6.

It has a rough idea of the elevation, but nothing else, apparently.

I kept it running for probably a half hour yesterday, hoping something would happen, but nothing did. Tried turning it on and off and moving the batteries around, too. Still nothing.

It has been working fine for months, and was perfectly all right the day before.

Help!

P.S. This is the unit that refuses to work with Windows 7, so I always have to haul out the old XP computer whenever I want to transfer tracks onto my Garmin National Parks East or National Geographic Topo! maps. So I haven’t searched for any possible updates yet, but are there really going to be any for a discontinued model?

 

[richard]

maybe the memory is full.

 

[psmart]

Is it only the satellite acquisition that's not working? Can you navigate through the various screens and menus OK?

If so, you may have a damaged antenna. I rolled my bike over a 60csx once and cracked the internal antenna structure, causing it to behave exactly as you describe. Although it's fairly strong, a good whack to the antenna stub can crack the rigid plastic structure inside. If you can test it with an external antenna that would confirm or reject any damage to the internal antenna.

 

[Raymond]

Hmm. How would I attach another antenna, and what would another antenna consist of? A coat hanger, something like that?

There’s plenty of memory. If I had filled up all 20 tracks it would refuse to save any more, but it would still acquire satellites.

 

[Nessmuk]

I have twice had a bad memory chip cause funky unexplained behaviors on a 60CSx. It took me a while to figure out that was the problem. Try to replace the chip with a new one, or even a reformat of the existing chip using a computer may work.

 

[Raymond]

Good bid, but I don’t think that’s it, either. I replaced the 8GB replacement chip I’ve been using for several years with the original 128MB one, and the result was the same. I removed the chip altogether, and the result is the same.

 

[Raymond]

I can navigate through the several screens without any problem. My start page info is still there. On the Computer page, it doesn’t know the time, the clocks don’t count the passing seconds, and there is no movement recorded.

 

[psmart]

There's a jack on the back for an external antenna, which are available for $20 or less. A google search will give you lots of options. Although they vary in sensitivity, almost any external antenna will give better satellite reception than the built-in antenna. Not sure about a coat hanger - I've never tried it!

 

[Raymond]

Thank you.

 

[DougPaul]

There's a jack on the back for an external antenna, which are available for $20 or less. A google search will give you lots of options. Although they vary in sensitivity, almost any external antenna will give better satellite reception than the built-in antenna. Not sure about a coat hanger - I've never tried it!

I don't think the coat hanger will work. I believe the GPS requires some current to be drawn (by the amplifier in the external antenna) to switch over to the external antenna.

Otherwise, a 1/4 wavelength piece of wire (about 5 cm at GPS frequencies) would likely work well enough for a test.

Doug

 

[DougPaul]

I can navigate through the several screens without any problem. My start page info is still there. On the Computer page, it doesn’t know the time, the clocks don’t count the passing seconds, and there is no movement recorded.

The GPS sets its time from the GPS signals.

It might be time to consider sending the GPS to Garmin for repair.

Doug

 

[Raymond]

Thanks.

I stopped at a Radio Shack, but the guy said they didn’t have an antenna for a GPS.

 

[DougPaul]

Thanks.

I stopped at a Radio Shack, but the guy said they didn’t have an antenna for a GPS.

Not surprised.

See:
http://www.google.com/search?ie=ISO-8859-1&hl=en&source=hp&q=gps+antenna&gbv=1&oq=gps+antenna

You want something like this one:
http://www.thegpsstore.com/Gilsson-MCX-amplified-antenna-w9-cable-P648.aspx (I don't have this one, but have several similar antennas.) They come in a variety of cable lengths and you want an angled MCX connector to match the connector on Garmin GPSes. Many come with built-in magnets to stick to a car roof. (You can also put a large steel washer in your hat for hiking.)

These antennas generally contain amplifiers to offset the losses in the cable. (Don't get hung up on antenna gains--too much will actually degrade the performance of the GPS.)

The cables are delicate and kink very easily, so be gentle with them.

BTW, an external antenna may or may not help--it depends on what is wrong with your GPS. (A bad internal antenna or bad antenna wiring is not the only possible cause of your GPS's symptoms.)

Doug

 

[richard]

I may be wrong . I`m just guessing. But , wouldn`t any GPS unit compare somewhat like any typical computer? If you save more DATA than the comp. is capable of storing, couldn`t that cause the problem? I would try removing some of your stored Waypoints, Routes, etc. and see if that helps.

 

[psmart]

If you save more DATA than the comp. is capable of storing, couldn`t that cause the problem? I would try removing some of your stored Waypoints, Routes, etc. and see if that helps.

If it's stuck on "Acquiring Satellites", with no signal strength shown, this would indicate a problem with the antenna or receiver.

 

[Jay H]

I presume Garmin still has a flat fee for fixing things? you might want to just open the baby up and take a look see if you can isolate the broken antenna....

Jay

 

[BlackSpruce]

Raymond, oddly enough mine (a Garmin 70S) did exactly the same thing this past Saturday. Luckily I did not really need it where we were bushwhacking. Then some 90 minutes later as we were on the summit of one of the two small peaks we visited it found satellites and itself! Over 15 years of GPS use I have occasionally noticed that when not in use for long periods it can take quite a while to find satellites, specially if last location was miles and miles away. What I usually do is have the GPS on while driving and approaching the "trailhead" of the day`s climb.

 

[DougPaul]

Raymond, oddly enough mine (a Garmin 70S) did exactly the same thing this past Saturday. Luckily I did not really need it where we were bushwhacking. Then some 90 minutes later as we were on the summit of one of the two small peaks we visited it found satellites and itself! Over 15 years of GPS use I have occasionally noticed that when not in use for long periods it can take quite a while to find satellites, specially if last location was miles and miles away. What I usually do is have the GPS on while driving and approaching the "trailhead" of the day`s climb.

I'm not familiar with the 70S, but there is a significant difference in the satellite acquisition procedures between the older and newer GPSes. The older ones sometimes exhibit the problem described above.* The newer GPSes (which Garmin describes as "high sensitivity" **) generally find some satellites within a few seconds of booting up if they have a decent skyview. The 60CSx is a "high sensitivity" GPS.

* Turning the GPS off and back on with the stationary GPS in a location with a good skyview for a period of up to a half hour often solved it.

** The critical difference between newer and older GPSes is not actually sensitivity--it is the use of large numbers of correlators. (It takes 2 correlators to track a satellite.) The SIRFstarIII GPS chipset used in the 60CSx has over 200,000 correlators and can search many time delays and doppler (frequency) shifts simultaneously. In contrast, many older GPSes had fewer than 100 correlators and had to search sequentially. If the GPS did not have a good estimate of its approximate position or a bad or outdated almanac (set of coarse orbital parameters) the search could be slow or fail.


Back to the OP's problem--I suggest that he consider sending in to Garmin for repair. There are a number of possible causes of the symptoms some of which cannot be diagnosed and/or fixed by most users.

Doug

 

[iAmKrzys]

** The critical difference between newer and older GPSes is not actually sensitivity--it is the use of large numbers of correlators. (It takes 2 correlators to track a satellite.) The SIRFstarIII GPS chipset used in the 60CSx has over 200,000 correlators and can search many time delays and doppler (frequency) shifts simultaneously. In contrast, many older GPSes had fewer than 100 correlators and had to search sequentially. If the GPS did not have a good estimate of its approximate position or a bad or outdated almanac (set of coarse orbital parameters) the search could be slow or fail.

This is quite interesting! When I read Wikipedia article on GPS and more specifically the section on navigation equations I thought that each gps would have some kind of non-linear least square solver such as Gauss-Newton or Levenberg-Marquardt and it would be enough to solve for time-delay, but it didn't occur to me that the chips would be performing the search for time-delay in parallel (I don't remember anything like this mentioned in the Wikipedia article.) Can you recommend any place on the Web where I could read more about this? I think I know enough basic math that I'm not scared of reading somewhat technical Web pages or papers. Tks!

 

[sardog1]

It's all part of Jade Helm 15.