+hookedoncache Posted September 23, 2004 Share Posted September 23, 2004 (edited) So how many satellites do you normally see in you GPSr and where are you located? I ask not because I'm new but it might help others to understand what to expect! Here in the Charlotte, NC area I usually see 4 to 6 and that seems a low number to me after reading for the last 2 hours the past threads around this topic. Maybe it would be a little more helpful if we include our GPSr model and conditions! 4-8 satellites clear sky closer to 8 in the woods 1 to 4 with signal loss hence the 1... Charlotte, NC Garmin 60CS Others? Edited September 23, 2004 by mlail Quote Link to comment
+tirediron Posted September 23, 2004 Share Posted September 23, 2004 Too many variables for me to give an average number.... Location, elevation/terrain/ time of day... I have had as many as 10 on an open beach as few as 1 (or 0) in deep woods... Vancouver Island, BC GPSMap76CS Quote Link to comment
thorin Posted September 23, 2004 Share Posted September 23, 2004 Too many variables for me to give an average number.... Location, elevation/terrain/ time of day... I have had as many as 10 on an open beach as few as 1 (or 0) in deep woods... Vancouver Island, BC GPSMap76CS What he said. Except I'm all over Ontario with a Geko 201. Quote Link to comment
+Prime Suspect Posted September 23, 2004 Share Posted September 23, 2004 So how many satellites do you normally see in you GPSr and where are you located? I ask not because I'm new but it might help others to understand what to expect! Here in the Charlotte, NC area I usually see 4 to 6 and that seems a low number to me after reading for the last 2 hours the past threads around this topic. Maybe it would be a little more helpful if we include our GPSr model and conditions! 4-8 satellites clear sky closer to 8 in the woods 1 to 4 with signal loss hence the 1... Charlotte, NC Garmin 60CS Others? It's not going to help you much. The SVs are not geosynchronous, but are in constant motion in relation to your position. The SV configuration now will be different than in an hour. Quote Link to comment
+Renegade Knight Posted September 24, 2004 Share Posted September 24, 2004 It's variable. Normally I always have enough for a 3D lock. Quote Link to comment
+Beta Test Posted September 24, 2004 Share Posted September 24, 2004 In VA i can usually get up to five, but when I'm in South Dakota I can get 20 or so on my RINO 120. Quote Link to comment
+CompuCash Posted September 24, 2004 Share Posted September 24, 2004 (edited) you need a minimum of 3 for position - four for 3D (Altitude) after that it increases the accuracy WAAS requires getting one of the 2 geosynchronous birds These are the absolute min's - neither my magellan nor the Etrex will show position on 2 birds - the instructions say about the same for the Magellan. wide open areas, tops of hills, and higher altitudes increase the ability to get more birds. low areas - trees! - hills - urban jungles (tall buildings) all block signals and chance for wider spread of birds. hope that helps - Edited September 24, 2004 by CompuCash Quote Link to comment
+Night Stalker Posted September 24, 2004 Share Posted September 24, 2004 I don't think I get a 3D lock until I have 4 sattelites. With 3 you don't get your altitude. Quote Link to comment
+strikeforce1 Posted September 24, 2004 Share Posted September 24, 2004 So how many satellites do you normally see in you GPSr and where are you located? If I recall correctly, on my Garmin 12 and eTrex Legend- it can display up to 12 birds on each. The G12 usually under clear sky conditiond will actually lock on to 6-8 birds. The legend in WAAS - I believe locked to 3 birds, in reg. mode - I think it locked into 5 birds the last time out. Location is Buffalo NY. SF1 Quote Link to comment
AJK Posted September 24, 2004 Share Posted September 24, 2004 I thought you needed 4, at least for the initial lock, as the fourth satellite is used to correct timing differences between the satellites' very accurate cesium clocks, and your GPSr's not quite so accurate clock. The method by which this is done is ingenious, and without it, GPSrs would probably not exist. It wasn't for the time discrepancy, only three would ever be needed for 3D, I think. Quote Link to comment
+AuntieWeasel Posted September 24, 2004 Share Posted September 24, 2004 It wasn't for the time discrepancy, only three would ever be needed for 3D, I think. Thanks for the explanationn. I always wondered why it wanted four, since three should theoretically be enough. And I often have a hard time getting and keeping 4, caching a lot of wooded areas in New England. Though I find getting and keeping the requisite number in a big city even harder. Quote Link to comment
+hookedoncache Posted September 24, 2004 Author Share Posted September 24, 2004 I have found that I am pressing enter (because it lost it's links) more time than I'd like while in th woods of NC. Quote Link to comment
+Eartha Posted September 24, 2004 Share Posted September 24, 2004 you need 4 for accuracy. Quote Link to comment
FreeFloat Posted September 24, 2004 Share Posted September 24, 2004 I think the most I've ever had lit up at once was 6 or 7. Garmin yellow e-Trex on a clear sunny day at high noon and NOT under trees Quote Link to comment
+Prime Suspect Posted September 24, 2004 Share Posted September 24, 2004 I thought you needed 4, at least for the initial lock, as the fourth satellite is used to correct timing differences between the satellites' very accurate cesium clocks, and your GPSr's not quite so accurate clock. The method by which this is done is ingenious, and without it, GPSrs would probably not exist. It wasn't for the time discrepancy, only three would ever be needed for 3D, I think. It only takes 3 to get a lock. A 3 SV lock actually defines 2 points, one on (or near) the earth's surface, and one in space. The GPSr assumes that you haven't left the planet, and ignores the other point. Quote Link to comment
+SixDogTeam Posted September 25, 2004 Share Posted September 25, 2004 Our MAG 310 generally gets about 7-8 in the sun. Quote Link to comment
+Anonymous' Posted September 25, 2004 Share Posted September 25, 2004 On my yellow eTrex I normally get 3-6 satellites. Quote Link to comment
+CompuCash Posted September 26, 2004 Share Posted September 26, 2004 you need a minimum of 3 for position - four for 3D (Altitude) after that it increases the accuracy WAAS requires getting one of the 2 geosynchronous birds These are the absolute min's - neither my magellan nor the Etrex will show position on 2 birds - the instructions say about the same for the Magellan. wide open areas, tops of hills, and higher altitudes increase the ability to get more birds. low areas - trees! - hills - urban jungles (tall buildings) all block signals and chance for wider spread of birds. Quote Link to comment
+GeoRoo Posted September 26, 2004 Share Posted September 26, 2004 On a cache I did several months ago in the mountains of WA state I could not get a lock with 3 sats. on my Ledgend. I had a good strong signal on 3 sats. and even pulled out my external antenna and still could not grab that 4th sat. It took 20 mins sitting on a rock in the open to finally get that 4th and a lock. When it finally locked on I saw that I was only 80 ft from the cache. I now have a 60cs and driving across E.WA with a clear view of the horizon in all directions I had 14 sats. The 150 or so caches I've done with my 60cs I've yet to lose a signal, so I've been very impressed with that. Quote Link to comment
+junglehair Posted September 26, 2004 Share Posted September 26, 2004 AJK was correct on the reason you need 4 satellites to get a lock. It needs 4 readings to solve 4 equations (X, Y, Z and Time). So three satellites would give you the position (X, Y, and Z), and the fourth corrects the time. Beta Test: It is not possible to pick up 20 satellites simultaneously with the Rino 120. First of all, the satellite orbits are designed in such a way that at least 4 satellites will be visible at all time for any location on the earth. There are 24 active satellites (plus 2 for WAAS), so even in the open skies of the prairies, I doubt that you would be able to see 20 of the 26 satellites at one time. Secondly, the Rino 120 is a 12 parallel channel GPS receiver. That means it can track up to 12 satellites at one time. So even if it were possible to see 20 satellites, your GPS could only lock onto 12 of them. I picked up 12 satellites on my Garmin Legend one day here in Rochester, NY. It was in the middle of the afternoon and I had a clear view of the sky. It was such a rare thing, I even took a picture: Generally, I find that the evening is the best time around here for picking up the most satellites. Quote Link to comment
Mr. TSP Posted September 26, 2004 Share Posted September 26, 2004 At best I've gotten 10, but I'm capable of getting 12. Quote Link to comment
+crash331 Posted September 27, 2004 Share Posted September 27, 2004 3 sats will be inaccurate often by as much as a few tenths of a mile. Quote Link to comment
MeisterCrew Posted September 27, 2004 Share Posted September 27, 2004 (edited) I have an eTrex Vista. I regularly get 5-6 satellites. Usually 7-8 on clear days. Most of the time I have no. 35 WAAS. Before I got my GPS, I read some very useful information on the Trimble website. It goes into great detail explaining the GPSystem. My manual for my Vista says that the WAAS is still experimental, and may not be fully functional. When I have that no. 35 locked on, my GPS has had an accuracy reading as low as 14'. Does anyone know if the WAAS is now fully functional?? I am in NE Pennsylvania. Edited September 27, 2004 by meisterjd1 Quote Link to comment
+Prime Suspect Posted September 27, 2004 Share Posted September 27, 2004 I have an eTrex Vista. I regularly get 5-6 satellites. Usually 7-8 on clear days. Most of the time I have no. 35 WAAS. Before I got my GPS, I read some very useful information on the Trimble website. It goes into great detail explaining the GPSystem. My manual for my Vista says that the WAAS is still experimental, and may not be fully functional. When I have that no. 35 locked on, my GPS has had an accuracy reading as low as 14'. Does anyone know if the WAAS is now fully functional?? I am in NE Pennsylvania. Just having a lock on a WAAS SV doesn't mean you've got correction data. You've got to look for the indicator (a "D" on Garmin units) for the other satellites. If you don't get at least 4, you're not using WAAS. If you're just getting an accuracy read of 14', you're probably not. That's easily attainable without WAAS turned on. Quote Link to comment
Dukie 'n' Dad Posted September 27, 2004 Share Posted September 27, 2004 With the old GPS 45, I was lucky to see 5 sats with the 1 channel receiver. Now, 8 is probably average and I get the WAAS correction more often than I ever thought would be possible. You need 4 sats for the time correction as stated above, but you also need 4 to get a 'Point'. One sat tells the receiver you are X distance from the sat. That number defines a sphere the radius of X. The second sat provides another sphere and where the two intersect is a circle. The third sat adds another sphere and where all three intersect is 2 points. The fourth sat's sphere will only intersect at one of the two points. The reason that the altitude is such a problem is that most of your signals will be comong straight down and the circle intersections are not all that far apart. virtically. It is the few near horizon signals that really help the altitude calculations. If you have 3 signals and they are all nearly overhead, the virtical difference in the two points could be only a few hundred feet. The unit can not determine which is the correct one. Quote Link to comment
+crash331 Posted September 27, 2004 Share Posted September 27, 2004 I have found that WAAS is hard to get a lock on with an internal antenna. I am guessing because it needs good reception to download the corrected date. However, when I am in my car and use my patch antenna, WAAS gets a strong lock and I have D's on all my sats within 2 minutes, and accuracy of about 4 meters. Quote Link to comment
+AuntieWeasel Posted September 27, 2004 Share Posted September 27, 2004 Yay! I got ten at once today, driving along the highway. Highest I've ever gotten. Left the receiver on the dash plugged into the laptop, running Fugawi (first time I've done this), tracking the whole drive. Uncle Badger drove, so I could play with the buttons and knobs the whole way. That was so cool, my head almost exploded. Quote Link to comment
gambit32 Posted September 27, 2004 Share Posted September 27, 2004 With my Geko 201, I typically get 5-6. Its very rare I get anymore than that (middle of a deep river valley) Quote Link to comment
+W7WT Posted October 2, 2004 Share Posted October 2, 2004 Just this afternoon here in Bremerton, WA. I decided I should let my 76C acquire satellites for a while. I set my external antenna on top of my carport and run the lead down to a stepladder. I also enabled WAAS and was running on external power supply. Within 20 minutes I was getting full scale on all bars with D on them. I was also getting number 47 WAAS satellite also with a D on it. It was indicating 6 feet. Without the external antenna it indicated 8 feet and I lost number 47. Never have seen anything on the other WAAS satellite, number 35. Now if I can get half that good this week when I go for my 700 milestone cache, Half Moon in SW Washington. Dick, W7WT Quote Link to comment
+Tread-n-Lightly Posted October 2, 2004 Share Posted October 2, 2004 With my 60CS I usually average around 7 - 10 here in South-East Texas. I average around 5 - 8 in tree covered areas. I have the external antenna, but get so excited when I start out caching, I keep forgetting to plug it in W5TTX Quote Link to comment
+planemaker Posted October 3, 2004 Share Posted October 3, 2004 The best that I have had on my Legend is 6......the worst is 2. In the Toronto Area in Ontario. Quote Link to comment
+Robespierre Posted October 3, 2004 Share Posted October 3, 2004 First of all: Maybe it would be a little more helpful if we include our GPSr model and conditions! No it won't! Any standard unit will do pretty much what the next one will do, at the same time and place. The "conditions" that matter are up above, and pretty much out of your control. As far as rain, the experts say it shouldn't bother you much - however a relatively thin cover of water over your car can bother you in a solid sheet. So hard rain will. A cloudy day should not bother you. But invisible "atmospheric stuff" will. I used to be concerned with only 4 satellites. That's a low day for me, seems like, but it works just fine. The days when I can't get accuracy under 20' are rare. Quote Link to comment
+graldrich Posted October 3, 2004 Share Posted October 3, 2004 (edited) I have a Magellan Meridian,I get 3 to 5 birds indoors and 6 to 8 outdoors most of the time here in Phoenix ,Arizona. Edited October 3, 2004 by graldrich Quote Link to comment
+Morock & Miss C Posted October 4, 2004 Share Posted October 4, 2004 There is only space for twelve satellites on the display screen of my, well used, Rino 120. Usually we get 4-8 including #47 WAAS. A couple weeks ago, on the side of a mountain wilderness area, during the afternoon of a crystal clear day, ten sats were locked in big time. The WAAS, was nowhere to be seen. I was on the east slope of the mountain and had already found the cache. Quote Link to comment
+hookedoncache Posted October 4, 2004 Author Share Posted October 4, 2004 Thanks everybody and now that we have all these replies I have another question that someone brought up. External antenna. I have a 60CS and with all of the lost signals that I get I was thinking about this but from some of what I read you need a power source? What external antennas do you recommend? Thanks, Marshall Quote Link to comment
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