Stupid sattelites

Your 330 has a hardware issue - contact tech support, and they will give you some steps to take to try & remedy the situation, and if that does not work, they'll arrange for a return for repair.

Be sure that your firmware is updated. And try to remember to get a satellite lock BEFORE you start moving. It takes the unit a shorter amount of time that way.

Snow and rain do not affect the GPS signal. Tree cover and tall buildings do, however. You want to have a CLEAR view of the sky for the best satellite reception.

The TomTom your aunt has likely has a high sensitivity receiver chip which the c330 doesn't have.

It would be interesting to know whether the unit exhibits the same problem when outside the vehicle. As you may already know, certain windshields can block the satellite signals. Also, a couple people recently reported that certain hybrid autos (with their electric motors emitting RF interference) are sensitive to GPS placement position within the vehicle.

An external antenna is always an alternative, if it is not a hardware failure.

I always thought this was the case, but now I'm not so sure. On a recent business trip in Ohio my GPS couldn't keep a signal during the heavy rain we encountered. The next day was clear, and there were no problems, along the same route.

Here at home I've noticed it takes much longer to aquire the signal when it's snowing.

Although we've never experienced it, I know people who have had problems with their satellite TV when it's raining or snowing heavily. Same concept, I think.

Paul

Check this out.

http://gpsinformation.net/gpsclouds.htm

Ahh yes, the wipers. Suspecting they might be the culprit, I actually did try to drive without the wipers a bit (safely, of course) and it did help. I'd forgotten about that.

Paul

Like so much "general" information available on the net, that does not tell the whole story. Maybe the people involved have never actually seen a "real" rain/snow storm.

Rain or snow that is heavy enough affects ALL radiated radio waves to some extent; the higher the frequency, the more attenuation and scatter. If the signal happens to be marginal to begin with then the particles in the air don't have to be as dense.

Very heavy rain or snow WILL affect GPS, Sattelite TV and sometimes even cell phones and UHF 2-way radio. Thankfully, storms of that intensity usually don't last very long.

I drive for a living. Rain, Snow, you name it, my GPSr is always on and from what I can tell I have full signal strength. I love to fiddle with the unit and check out the signal strength. Cool feature.

Well, Joe Mahaffey is very well respected in the GPS community.

Here are some other sources.

http://gpstracklog.typepad.com/gps_tracklog/2005/09/does_clo...
http://www.hacking-gps.com/articles.php?url=2&id=20050310203...
http://www.eomonline.com/Common/Archives/1995nov/95nov_gps.h...

I have both a c330 and a 660 the 330 does take a few seconds longer to acquire a signal( 30-40 sec.) but I do not experience the problems you are having. I agree with the suggestion.... contact garmin support. You have a firmware or hardware problem.
gusb

I have a c330 and nothing like this apen to me. If your in a city with big billding's or tunnel's ok....

My 350 is really inconsistent, and I still haven't quite figured out why. Even when weather is about the same, sometimes it's an almost immediate lock, other times it can be 5 or 10 minutes. And this is all turning on in the same exact place.

Be sure your car does not have passivated windshield glass, which can block GPS satellite signals. Here is a place that carries external antennas.

http://www.navsphere.com/product_info.php?products_id=1024

Bob

And YOU are well respected here....for good reason, so I do NOT want to start an arguement but.....

I have been a technician and an engineer in the field of radio and electronics since before there was such a thing as GPS and cell phones.

It is a simple fact of radio wave propagation that objects in the path will scatter and attenuate the signal. The amount of scatter and attenuation is directly proportional to the size and density and composition of the interfering object(s).

Without a doubt, MOST rain or snow storms will NOT have a detectable impact on GPS (or other radio) signals. It is, however, a fact that a VERY HEAVY rain or snow storm can disrupt them. The clouds that produce intense storms can tower to near 100 thousand feet at times and can be packed with rain, snow and ice. High frequency signals do not like going through something like that. And forget the theory, I have SEEN severe storms disrupt TV, cell and UHF radio communications. I have not seen it with GPS 'cause I've only had one for 3 months. A GPS relies on signals from multiple sources so it should be affected less....but it is NOT immune. If you are in a marginal condition to start with, you could easily lose sync for a while.

Your sources are not wrong, just incomplete. And I readily admit that what I am describing is rare but it DOES happen.

Remember we just shot down a stupid satellite. lol
My c330 lost satellite reception a couple of times. It get aggravating when you are following directions and lost satellite reception appears on the screen. What I did was purchase an external antenna. When I would get the L.S.R. I would stop and plug in the antenna and put it on the dash. It was like every little bit helped.

Joe

We have to remember that we are constantly receiving data from multiple satellites at once, spread out in all directions. It is almost inconceivable that a weather front would be large enough to affect all of them at once. I have driven through several heavy snowstorms this winter, and my accuracy with the Nuvi 350 has only gone from the usual average of 14 feet to 20 feet while driving through the storm. This was in a snowstorm heavy enough that I was having trouble reading the signs on the interstate.

I'm quite certain that a very heavy activity could block a satellite signal for a short while. But that would only cause me to lose one satellite lock, not all of them.

You need at least 3 satellites for the GPS to figure your position. I think that there are 24 sats all together but many won't be in your line of sight.

I have a Garmin aviation portable GPS that I bought in 1991. It would lose signals all the time because of thick clouds or precipitation. Anything that put enough of a barrier between the satellites and the receiver could cause a problem. Sunny days were great, although some people needed to put on an external antenna to keep the signal from being blocked by plexiglass.

The reason water droplets are not a problem today is not because physics has changed or clouds and rain have changed, it's because the technology has improved. Today's chipsets are a lot more senstive and efficient, so problems are rare. And the satellites probably gradually get replaced with newer ones that have better transmission technology. Still, I believe that if you get into a Florida style super downpour, you are going to lose the signal.

With mine, I have to have at least 4 of them to get a lock.

On my dad's t2, he has to have 3

That's interesting. Accuracy should be fine with 3 since that's all that's needed to triangulate a position. 4 should only be needed to get altitude also.

That's assuming you're carrying a synchronized clock. Typically a 4th satellite is used to provide the initial time sync, adjusted for transmission delay, then theoretically you'd only need 3 to maintain 2D position lock. This is coming out of my head, so I could be all wrong.

Pseudo Random Noise code correlators (C/A & P)love noise. In most cases the more noise, the better the code lock. The more clouds, the more noise. Bring in the rocket scientists and they'll start blabbing about ionosperic and atmospheric modeling using L1 and L3, Block 1 and Block 2 satellites. But this is the subject for another forum.

Actually, it is called trilateration, not triangulate. But yes, you only need 3 of them to do this. To get altitude, you don't need the fourth one, altitude is calculated by how fast it takes for the signal to go from the sat to your receiver.

That's an improvement then for altitude. When I was flying with my 1991 Garmin 195 GPS, I would often lose the signal from one satellite and the GPS would say "Altitude Not Available". But I would still retain the ability to navigate without altitude.

I could be wrong, but that is what I was under the impression of. By no means am I an expert in GPS, many here are far more knowledgeable.

Take a look at this pdf guide on Garmin's site.

http://www8.garmin.com/aboutGPS/manual.html

http://www8.garmin.com/manuals/GPSGuideforBeginners_Manual.p...

You need the fourth satellite for altitude.

Oh ok, so I have been wrong before, I wonder why the T2 require only 3, I didn't take notice if the alitude showed on my father's when he had just 3.

Not only that older satellites are being replaced by satellites with newer technologies but also the receivers are not what they were in the 90s, back then a one or two channel receiver was the norm, later they went up to twelve channels receivers, the one channel receivers could only talk to one sat at a time.

That's not entirely true. Three satellites give 2 possible solutions, one of which is near the Earth's surface, and the other of which is at approximately twice the orbital altitude of the satellites, so it can be discarded for typical applications.

you are saying that 3 satellites can tell us that our altitude is somewhere between the highest and lowest points on earth (or, for planes, somewhere in the atmosphere) rather than 48,000 miles in space? Thank you. And the non-typical application would be what? I suppose all those moon rockets.

I have noticed my nuvi 350 is inconsistent when it starts up, sometimes it takes a minute, sometimes 5 or more.

I assume that it has been updated from Webupdater. It will find the satellites quicker whenever it is turned on at the same location where it was last turned off.

it takes longer if you cut off the power and restart it in another location.

I never have problem with Garmin C340.

I was in Hawwaii with a garmin 250 and it would only get a signal when the power cord was plugged into car. If I took it out of the car to run on batteries the satelites would drop off. Back in Canada I can go anywhere without the power cords and get satelites. I thought maybe the time zone setting was the problem?

I have the same experience with my nuvi unit, sometimes the unit starts up immediately and other times it will take several minutes.

Damn straight

Get Garmin Get in

different unit / different sensitivity chip

Easy with the language, please.

Actually let me correct myself it doesnt ALWAYS have a problem but alot of the times it does

My c330 wil almost always pick a signal pretty quick rain or shine. Although my Garmin Mobile xt on a Blackjack phone always has trouble in bad weather. My kids think it's a riot the last time I was trying to use the tracking feature on a long walk in what looked to be some bad weather showing up the unit told me I was ut in a Canada somewhere
(I live near Chicago) moving at 198 miles per hour. I'm guessing the reciever in my phone is'nt to hot?