GPS Reception in a closed room?!?

[Where's_North]

Last night I recieved via mailorder my first GPS, a Garmin GPSMAP 76S. So after tearing off the shipping packages and inserting batteries I am walking around my apartment, seeing what kind of reception I can get. I'm monitering the satellite page. So for kicks I go into the restroom and close the door. I constantly get at least two very strong signals with another three to four of varying strengths. In any given five minute time span I will see a momentary though distinct drop in all of them leaving only one or two grey bars (aquiring almanac data). With equal frequency I will see a great increase in the power and number of recieved satelittes. I'm averaging 30 foot accuracy. After going outside and marking some waypoints with proper data: it confimed the accuracy in the closed room.

 

My point is I didn't think this was possible (even with the quad helix). Nothing I've read led me to think I could recieve any real signal at all in a closed room, let alone enough to maintain virtually constant 3D Location.

 

After more testing around the apartment I found being surrounded by walls or proximity to an open window did not matter so much as holding the unit above waist level and holding it veritcally. Drop it below waist level and it loses good reception real fast. If it matters I'm in a 2 story apartment in NW Ohio.

 

I have only used a friends Garmin EMAP (model# unkown, but its bout three years old). So I wasn't quite sure what to expect, but I didn't expect that. I can't wait to get it under thick Indiana tree cover.

 

My point is, Is this kind of reception to be expected or am I just getting lucky?

 

One other side note... I was quite wary of the buttons being above the display, but after about three seconds it made perfect sense.

 

I would also like info on a webpage that posts satelitte information. Which ones are up there, which #'s are waas and such. I wadded through numerous searches with no specific information given. Any good links would be much appreciated.

[+jtice]

Well, I have an etrex Vista,,, (patch antena)... I'd say your lucky. LOL

 

I can get a signal in cars, by house windows, and sometimes in my garage, but not in the house.

 

Even if you are getting signal locks, that doesnt nessesarily mean they are correct. They are probably doing alot of bouncing around before they get to the GPSr.

[Team Kender]

The building I work in is surrounded by windows but I get absolutely zero reception. It's on the first of two floors. But in my apartment with much less windows I get reception just fine. It's on the top floor. Could be the elevation or number of floors above you makes a difference.

Are you on a top floor?

 

Team Kender - Willow and Dan exploring the Bay Area backroads!

[the_wanderer]

quote:

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My point is I didn't think this was possible (even with the quad helix). Nothing I've read led me to think I could recieve any real signal at all in a closed room, let alone enough to maintain virtually constant 3D Location.

---

 

Congratulations.. You have observed completely normal behavior for a GPS Map 76S... Yep, that's the way it works.. Get used to it, 'cause that's the way it works most of the time, too....

[+TotemLake]

I actually think it has to do a lot with the amount of steel above your location. I get good lock on satellites in all parts of the house including the lower crawlspace with exception of high metal content such as under the washer and dryer and under the kitchen area.

 

When I walk into a facility with a lot of girders such as a bowling alley, I lose satellite lock even though I have glass doors nearby. I have also noted my EPE increases the more centered in the car my GPS becomes, and less EPE when I have it directly under the windshield. I can only surmise that I narrow down my window of opportunity (no pun intended) to peripheral openings when there is a large enough expanse of steel overhead.

 

There was a review I read when I was researching GPS's that when the receiver is placed on the hood of the car, the reception actually becomes worse and took longer to gain a lock than when it is away from the car, again the overall cause points to the amount of steel. I haven't really tested this phenomenom although sometimes when I turn on the GPS in the car, the lock is slower than when I hold it outside the window.

 

IF I relocate that review, I'll place that pointer here.

 

Cheers!

TL

[peter]

Sounds pretty normal. I have a III+, eMap, and also used a GPS12. All three usually get a satellite lock in any of the upstairs rooms (regardless of windows) of our house which has a spanish tile roof. The type of antenna doesn't matter since two of mine have patches and one has a quad helix. Overall the eMap (patch) is just a bit more sensitive than the other two, but the difference is small and may be due to sample-to-sample variations.

 

The things that will stop the signals best are those that contain metal or water. Many building materials are pretty transparent to the 1.5 GHz frequency GPS signals.

[+Renegade Knight]

Water in the tree canopy can block signals. The wood in your roof does degrade your signals but isn't as effective at blocking it as tree canopies. So some people will get reception in their house. Others won't. Lots of things can impact this.

 

So far I've not read any case in these forums where people got reception in their basements.

 

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Wherever you go there you are.

[3fros]

I was checking out the same thing just last night. I had my GPS at least 10' away from the nearest window/outside wall, toward the center of the house and I was getting 5 satellites at full strength with another 2 bars going up and down.

[Cache Canucks]

It has as much to do with what is between your GPSr and the sky (and whatever 'it' is made out of) as the GPSr itself. My Vista's patch antenna will regularly lock on 3-5 satellites (with an accuracy of approx 8-20 meters) from the inside of my house ...even in a room without windows. However, when I try the same 'indoor trick' from my 8th floor corner office at work (which has floor to ceiling windows wall-to-wall on two of its walls), the Vista is absolutely 'dead' ...the reason being, although the office has a clear and elevated view of the sky, the treated glass (which looks mirrored from the outside) and the floors above me completely block the satellites' signals. The same thing can determine how well (if at all) your GPSr will function from the inside of your car. My Vista's internal patch antenna works just fine when used inside my Acura, but would be useless in a vehicle with metallic treated glass. It sometimes doesn't take much to impede the signal coming from a 50 watt satellite-borne transmitter that's in an orbit 11,000 miles high ...but it's often amazing how well (and under what circumstances) the system *can* work!

[Kerry.]

Certainly wouldn't rely on hit and miss signals in buildings.

 

Would be rather simple for 911 purposes on mobiles but unfortuneately there's a sticking point, buildings/obstructions really don't give much reliability to GPS.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[+NJGeoFam]

I was surprised at the reception I got as well.

Got my SportTrak Pro on Xmas day and was getting a 3D signal in my house during a Nor'Easter! When I "drilled" down to 100 ft resolution, I could actually watch my track through the house!