Weak Satellite Signals This Past Weekend May 24-26

[+Larry&Wesley]

I'm posting this on Monday night after the Memorial Day weekend and have experienced weak satellite signals here in San Antonio, TX, for the past few days and wondering if anyone else has. I have three Magellan GPSr's and one Garmin GPSr and all are getting weak satellite signals in my cars. Outside the car I get seemingly normal signals with up to 13 satellites, but inside either of my cars the signals drop to unusable levels.

 

I have checked all the Magellans (2 Explorist 600's and 1 Explorist 500) with secret menu # 3 to confirm reception of WAAS Sats 135 and 138. Out of the car they show accuracy as low as 10 feet with WAAS, but as I place them inside the car on the windshield mount, they all loose lock and sit there trying to lock on the weak signals.

 

The Garmin is a 60CSX and it maintains lock inside the car, but drops to 3 or 4 sats and accuracy goes to 70 to 100 feet. The Garmin has WAAS enabled, but I wasn't sure how to check it further.

 

I have used all of these GPSr's in the same two cars for over a year now with very successful results with good strong signals. One of the cars has a moon roof and I can usually use the GPSr anywhere in that car with no noticeable loss of signal strength. The weather here has been blue skies with a few white clouds, but nothing that should be blocking the satellite signals.

 

There have been no changes to the cars or items mounted on the dash or windshield and no I didn't take the car and get the glass tinted. I even cleaned the windshield really well thinking there may be a coating of something that had gotten on the glass that was blocking the signals. No change after cleaning.

 

Has anyone else noticed the weak satellite signals for the past few days or have any suggestions as to what may be causing my problem?

[+TexasGringo]

***San Antonio, TX***

 

I'm in Dallas (Ok, Plano/Richardson line) and have no problems. My Garmin 60Csx locks on and shows about a 12 foot accuracy.

[+Team LRS]

I'm posting this on Monday night after the Memorial Day weekend and have experienced weak satellite signals here in San Antonio, TX, for the past few days and wondering if anyone else has. I have three Magellan GPSr's and one Garmin GPSr and all are getting weak satellite signals in my cars. Outside the car I get seemingly normal signals with up to 13 satellites, but inside either of my cars the signals drop to unusable levels.

 

I have checked all the Magellans (2 Explorist 600's and 1 Explorist 500) with secret menu # 3 to confirm reception of WAAS Sats 135 and 138. Out of the car they show accuracy as low as 10 feet with WAAS, but as I place them inside the car on the windshield mount, they all loose lock and sit there trying to lock on the weak signals.

 

The Garmin is a 60CSX and it maintains lock inside the car, but drops to 3 or 4 sats and accuracy goes to 70 to 100 feet. The Garmin has WAAS enabled, but I wasn't sure how to check it further.

 

I have used all of these GPSr's in the same two cars for over a year now with very successful results with good strong signals. One of the cars has a moon roof and I can usually use the GPSr anywhere in that car with no noticeable loss of signal strength. The weather here has been blue skies with a few white clouds, but nothing that should be blocking the satellite signals.

 

There have been no changes to the cars or items mounted on the dash or windshield and no I didn't take the car and get the glass tinted. I even cleaned the windshield really well thinking there may be a coating of something that had gotten on the glass that was blocking the signals. No change after cleaning.

 

Has anyone else noticed the weak satellite signals for the past few days or have any suggestions as to what may be causing my problem?

 

Hi

I had bad problems on monday with my tomtom loosing signal when i was trying to find my way to a drop off......so maybe there was a problem in the skys above

[+Woodstramp]

I'm posting this on Monday night after the Memorial Day weekend and have experienced weak satellite signals here in San Antonio, TX, for the past few days and wondering if anyone else has. I have three Magellan GPSr's and one Garmin GPSr and all are getting weak satellite signals in my cars. Outside the car I get seemingly normal signals with up to 13 satellites, but inside either of my cars the signals drop to unusable levels.

 

I have checked all the Magellans (2 Explorist 600's and 1 Explorist 500) with secret menu # 3 to confirm reception of WAAS Sats 135 and 138. Out of the car they show accuracy as low as 10 feet with WAAS, but as I place them inside the car on the windshield mount, they all loose lock and sit there trying to lock on the weak signals.

 

The Garmin is a 60CSX and it maintains lock inside the car, but drops to 3 or 4 sats and accuracy goes to 70 to 100 feet. The Garmin has WAAS enabled, but I wasn't sure how to check it further.

 

I have used all of these GPSr's in the same two cars for over a year now with very successful results with good strong signals. One of the cars has a moon roof and I can usually use the GPSr anywhere in that car with no noticeable loss of signal strength. The weather here has been blue skies with a few white clouds, but nothing that should be blocking the satellite signals.

 

There have been no changes to the cars or items mounted on the dash or windshield and no I didn't take the car and get the glass tinted. I even cleaned the windshield really well thinking there may be a coating of something that had gotten on the glass that was blocking the signals. No change after cleaning.

 

Has anyone else noticed the weak satellite signals for the past few days or have any suggestions as to what may be causing my problem?

 

I was cruising the archives for GPS topics on a hunting board I read. Found one post by a member there that may have something to do with this topic on signal loss.

 

The member said he was former military and had been through survival/orienteering training in the past. He said that in one of their orienteering exercises that some guys had civilian GPS units along with the ordinary map+compass and that at the beginning of the exercise they were allowed to use the the GPS units to navigate, but after a certain time the base generated a jam signal to screw with the GPS units. He made is sound like this is something that can be done in a small area. San Antonio certainly has a lot of military facilities, so maybe this is a possible explanation of your signal loss over that period.

[+JDandDD]

Don't know whether this explains your issue because I'm not sure what weak signals means for sure but, one has to know what the satellite cluster overhead is really like. If they are all near the horizon at your location your GPS may not pick up all of them.

 

But there has also been a recent problem with the entire 32 satellites. This week, #1, was taken off line completely. There are now only 31 active. I've noticed on the live tracking sites that that has actually been leaving a bit of a hole over North America during the afternoon in North America.

 

As well, there have been a number of times that the status of 138 has changed from NPA (non-precision approach use only) to NM (not monitored) which means live but not really usable for WAAS. These changes have happen for periods of just a few minutes.

 

However, all this combined could mean that there are times when signal reception is not quite the same, at least on the civilian channel we get to use.

 

JD

[n2stitch]

I had trouble with my 60CSx for the first time ever on Saturday. It took a long time to lock, and lost reception a few times (for a few hundred feet). I'm in the St. Louis metro area, but was a bit further south and west at the time. No idea if it's related. I was wondering if software v3.00 was the culprit.

[SiliconFiend]

But there has also been a recent problem with the entire 32 satellites. This week, #1, was taken off line completely. There are now only 31 active. I've noticed on the live tracking sites that that has actually been leaving a bit of a hole over North America during the afternoon in North America.

It's about dang time. I've been frequently seeing #1 directly overhead for quite a while but unable to get any signal from it, so it has been occupying one of my channels but not giving any position information. Good to get it out of the way. Bring on the new sats!

[frozenflyboy]

 

I was cruising the archives for GPS topics on a hunting board I read. Found one post by a member there that may have something to do with this topic on signal loss.

 

The member said he was former military and had been through survival/orienteering training in the past. He said that in one of their orienteering exercises that some guys had civilian GPS units along with the ordinary map+compass and that at the beginning of the exercise they were allowed to use the the GPS units to navigate, but after a certain time the base generated a jam signal to screw with the GPS units. He made is sound like this is something that can be done in a small area. San Antonio certainly has a lot of military facilities, so maybe this is a possible explanation of your signal loss over that period.

 

Not meaning to put conspiracy theories in here but there is a very big concern with the GPS system in that the signals are very weak by nature and can be interfered with by even cellphones (if the cellphones are close and their signals are strong. This is one reason why cellphones are banned in aircraft. (article from pro pilot)

Also the FAA ran (or is running) some testing (I believe in New Mexico but don't quote me) on the very serious threat of jamming GPS signals. Apparently GPS signals could be jammed very easily with a transmitter the size of a cigarette package. The FAA was advertising for people with private aircraft to participate in the study as I recall.

I guess the FAA is not aware of the serious threat to "Geocaching" by these criminal minds.

[+GPSlug]

Certified aviation receivers have interference rejection requirements, so they aren't as bad off as handhelds.

 

(side note, I doubt this is what's happening)

A number of years ago, there was a particular signal amplifier used in Radio Shack TV signal boosters and other products that could go flaky and start putting out a bunch of in-band GPS interference. In one instance, the U.S. Coast Guard was hearing complaints about not being able to get GPS in a particular harbor, but it was very intermittent. They were eventually able to track it down to a personal boat that had one of the TV amplifiers, but the interference would only be in-band when his TV and exterior lights were on at the same time.

 

But if it's a difference between in and out of the car, it could be some interference inside the car. I can watch my satellites blink in and out more when I'm in the car when I turn the CD player on. It's especially noticeable when I'm doing a cold start (old ephemeris). Acquisition is considerably better with the CD player off. My brother's XM-Radio receiver is even worse. On my old Legend, you could watch the bars drop to half of what they were when you turned the XM on and they were in the same area of the dashboard.

[frozenflyboy]

Certified aviation receivers have interference rejection requirements, so they aren't as bad off as handhelds.

 

Interesting post GPSlug.

Aircraft receivers have two separate systems which are monitored and if they do not jive both are considered not reliable and are kicked off the line.

The last time I checked they had finally decided that for WAAS approaches (much lower landing minimums) there would also have to be two separate antennae or two GPS systems. (which would mean 4 actual receivers)

Now I am not an aircraft radio person so this is the dumbed down pilot version.

[+GPSlug]

Certified aviation receivers have interference rejection requirements, so they aren't as bad off as handhelds.

Interesting post GPSlug.

Aircraft receivers have two separate systems which are monitored and if they do not jive both are considered not reliable and are kicked off the line.

The last time I checked they had finally decided that for WAAS approaches (much lower landing minimums) there would also have to be two separate antennae or two GPS systems. (which would mean 4 actual receivers)

Now I am not an aircraft radio person so this is the dumbed down pilot version.

The requirements* would apply to all of the receivers. They're not going to be as stringent as military receivers, though. Consumer units have no applicable requirements.

 

*(part of RTCA DO-229 and, I believe, some other test procedure document)

[TexasTrails]

As soon as I read your post Larry&Wesley it reminded me of an outing on Saturday. I drove from San Antonio to Atascosa County to do some maintenance out on the hunting property. I tried a new route my Garmin V suggested and it seemed to do fine... this was around 11:30 am when I got to my stop. No problems using the Auto-route.

When I was packing a few things for the chores; feed, game camera...I fired up the Explorist 500 so that I could mark some waypoints. I noticed that it took an unusually long time to lock on. I thought it might be because I had travelled 20 or so miles from the last time I had it on. After it "locked on" I went about my chores, no problems...this was about 1 pm. As I left the area, I left the Explorist on as I wanted to track the new route back to the house. I am running the Topo 3D and wanted to see it in 3D on the PC! The 500 did display the hourglass twice along the route which was mostly farmland. This was about 1:15 to 2 pm .

This was unusuall for the Explorist as it seemed to work great the rest of the day. I even motored about town in another vehicle later in the day and no problems. Hope everything settled down for you and yours.

[+Larry&Wesley]

Thanks to everyone that has responded in the thread. I tried again last night, this morning, and this afternoon and in the same cars with the same GPSr's in the same windshield mount I am now getting 10 to 12 satellites all the time in the cars. I don't have XM satellite radio in either car, though I do have an Escort X50 Radar Detector in one of the cars. I tried turning it on and off, mounted and not mounted over the weekend and it didn't seem to make any difference. It is in the car I drive most of the time with the moon roof and all usually works perfectly. When the signals are strong I can move the GPSr's around in the car with little affect. I enjoyed the response about the CD player causing interference, but I haven't been able to identify anything in the cars that is causing the problem.

 

I am wondering if the satellite controllers are reducing the transmit power on the birds at times to charge the batteries or for maintenance purposes. Does anyone know of plans for new satellites to replace the old ones?

 

I will continue to monitor performance and will report back if anything is identified locally causing the issue.