Delorme GPS Outage Issues

[Bill Tabor]

I have a USB Delorme Earthmate mounted on the upper inside of my window in my Tahoe. Saturday chasing in the Panhandle in the heat of battle with tornadoes on the ground and hail cores overhead I was having lots of trouble with it. Everytime I would turn a corner it would lose the gps and need to try and acquire again. It seemed to be fine in clear air on the way up and back. Have any of you have similar problems with these things? This is kind of a big issue. You need your gps while in the thick of it. Is it possible the overhead canopy of rain and hail can kill or limit the gps signal getting in? Any suggested solutions here?

Thanks

 

[John Diel]

Is the puck under a shaded area of the windshield? Sometimes that in addition to overhead storms may limit the reception. Mine is on the dash between the wipers and I haven't had a problem with it.

Obviously a clear sky will give you a stronger signal. Less to reflect back into space. I have noticed on my wife's little GPS Navigator system, it will see fewer satellites than my delorme puck. It's attached to the windshield with a suction cup just under the mirror. If I move it down to a more clear area of whindshield, more sats show up.

Consider moving it.

You might also consider having paper maps and brush up on old style navigation skills as well. Delorme puts out a very nice road atlas and topo gazetteer for each state. They are certainly worth their weight and will fit very nicely under a seat.

 

[Van DeWald]

I'm beginning to wonder if they weren't satellite issues in general this past Saturday evening. The NWS had trouble with the SBN uplink and subsequent NOAAPORT downlink. The signal kept going in and out. Several folks also reported that their XM went down for a time in the field, and now you're reporting GPS satellite troubles. As far as I know, these are 3 different satellite systems, and all had trouble at about the same time. Hmm.

 

[J Kinkaid]

Aren't we still in sun spot cycle ?

 

[Robert Edmonds]

Aren't we still in sun spot cycle ?

I believe we're closer to the solar minimum than maximum.

 

[Jayson Prentice]

I would say location is the big problem... Sunday while I was out for a nice drive with some fellow chasers, I couldn't get a signal on mine for a longest time! I was in the middle seat of a van, putting the puck up about halfway on the dash, straight up was the windsheild/top of the van. Once we stopped and were waiting I managed to rig it up and get some more length, putting it about half way down the windsheild and from there on out didn't have a single problem with it even while in some very heavy downpours...

So I would definitely think about putting it up more on the dash, as far up as you can to get the most sky above it. Putting it off the side definitely limits its' range, especially in some tough situtations where you need as many satellites as you can.

 

[Greg Stumpf]

Is it possible the overhead canopy of rain and hail can kill or limit the gps signal getting in?

I say definitely possible. I've had this issue with GPSs ever since starting to chase with them years ago. However, newer GPSs seem to do a better job with this. I even experienced the effect with a satellite phone I used for chasing in 2004. This usually occurs under what I call "thick anvils", or under the echo overhangs. Not sure if the signal is being attenuated by the precip, or if the electrical charge in the anvils (re: anvil "zits") are causing the interference.

 

[Bill Tabor]

You might also consider having paper maps and brush up on old style navigation skills as well. Delorme puts out a very nice road atlas and topo gazetteer for each state. They are certainly worth their weight and will fit very nicely under a seat.

I don't believe it's under a shaded portion. It is toward the top at a slight angle out.

Funny you mention the old school paper way. I always bring my maps just for that reason and for some reason this night I didn't have them. Go figure.
However even without the gps the Street Atlas background still works as a map.

 

[Bill Tabor]

I'm beginning to wonder if they weren't satellite issues in general this past Saturday evening. The NWS had trouble with the SBN uplink and subsequent NOAAPORT downlink. The signal kept going in and out. Several folks also reported that their XM went down for a time in the field, and now you're reporting GPS satellite troubles. As far as I know, these are 3 different satellite systems, and all had trouble at about the same time. Hmm.

Yeah I was having some trouble with XM also. The application was running fine, but at one point the radar stations for LBB, and AMA (probably others) were down. This was right about the time we were under big hail at night with a tornado inbound to our location.

Of course everytime my gps really messed up, I would have to reboot otherwise the Threatnet might screw up.

 

[Bill Tabor]

I say definitely possible. I've had this issue with GPSs ever since starting to chase with them years ago. However, newer GPSs seem to do a better job with this. I even experienced the effect with a satellite phone I used for chasing in 2004. This usually occurs under what I call "thick anvils", or under the echo overhangs. Not sure if the signal is being attenuated by the precip, or if the electrical charge in the anvils (re: anvil "zits") are causing the interference.

Yes, these were some big storms...hail and tornadoes. Many feet of precip above.

I wonder if it is possible to mount them outside - such as on the roof? Would they be water proof?

 

[brian morgan]

I have a USB Delorme Earthmate mounted on the upper inside of my window in my Tahoe. Saturday chasing in the Panhandle in the heat of battle with tornadoes on the ground and hail cores overhead I was having lots of trouble with it. Everytime I would turn a corner it would lose the gps and need to try and acquire again. It seemed to be fine in clear air on the way up and back. Have any of you have similar problems with these things? This is kind of a big issue. You need your gps while in the thick of it. Is it possible the overhead canopy of rain and hail can kill or limit the gps signal getting in? Any suggested solutions here?

Thanks

Bill, I have a 2005 Tahoe and I have experienced the same problem. I have tried to move the puck around in different places on the dash but nothing has helped. The only thing I can think of is the ONSTAR GPS antenna on the roof.. Maybe interference I don't know.

 

[John Diel]

I've heard that on some windshields, the coating, or the laminate may cause some issues. I don't know how true it is, but it seems like it was something to do with polarization.

Yesterday and today, I had no issues in getting signal.

Here's another option. Try an external GPS antenna.

http://cgi.ebay.com/NEW-GlobalSat-B...52QQihZ007QQcategoryZ4668QQrdZ1QQcmdZViewItem

http://cgi.ebay.com/Holux-GR-213-US...W0QQitemZ180110903319QQihZ008QQcategoryZ14849
http://cgi.ebay.com/Holux-GR-213-US...QQihZ008QQcategoryZ148490QQrdZ1QQcmdZViewItem

 

[Jeff Snyder]

I have intermittent problems with my DeLorme Earthmate GPS. There were chases last year during which I could not get a signal for more than 10-20 seconds at a time. This year, it's been quite a bit better, and I haven't moved where I put the GPS either (it's always on the front dash).

I have noticed, however, that I lose the GPS signal when I transmit on my ham radio when the power is above ~15W (I think my radio, on 2m, does 5w, 15w, 25w, and 50w). So, if I have it on mid1 or high power, the GPS signal drops. FWIW, I have a triband antenna that is 5/8-wave at 2m, so there is a decent amount of gain.

Have you noticed that you lose the GPS signal when transmitting? frequently?

 

[mrobinett]

I use the Garmin GPS 18-USB model, it is truly a "puck" and has a magnet built-in, Ive had it on my roof for two years, no problems, it outputs the Garmin protocol, Street Atlas can interpret it as well as Franson GPSGate, others may not. Its a good deal at $80.

http://www.gpscity.com/item-garmin-gps-18-usb/oem18usb.htm

 

[Tony Cook]

I have noticed, however, that I lose the GPS signal when I transmit on my ham radio when the power is above ~15W (I think my radio, on 2m, does 5w, 15w, 25w, and 50w). So, if I have it on mid1 or high power, the GPS signal drops. FWIW, I have a triband antenna that is 5/8-wave at 2m, so there is a decent amount of gain.

Prior to 2006, I would sometimes chase with a handheld Garmin. Don't remember the model (it was a loaner), but it was an older unit with an LCD screen. Had an older analog-8 video camera back then (also a loaner) that had a fairly big LCD viewfinder display built into the back, unlike newer models that have flip displays.

Every time I would hit record with the camera display on, my GPS signal would drop. Obviously, this was a huge hassle when getting into the business end of the storm. Finally, I put two and two together, and would disable the camera display except when I absolutely needed it. Definitely some kind of weird interference pattern was going on.

FWIW, I have a newer (still old) camera now, and a "dumb" GPS receiver (it's an Ay-Ay Sir, shaped like a credit card instead of a puck) that rides under the rear window. Never have any problems with this combo, regardless of the LCD screen being on or off. The Ay-Ay has to be oriented correctly (it matters which side faces upward), but as long as it is pointed up, it has had very few dropouts.

TonyC