GPSR reception expectations

[+CachingHomer]

I purchased a receiver about 4 months ago, and am not sure if there is something wrong with my unit or my expectations. I am intentionally not mentioning the brand (to avoid debates about brand quality), but I did pay around $300. Under what curcumstances would I expect to get poor reception? Some examples of times when I have had bad reception:

 

In car (sometimes laying on the dash)

 

Outside with mostly clear skies and the occaisional cloud. (only happened once)

 

Outside with a consistant low level cloud cover

 

I do not always lose the signal under these conditions, but every so often.

 

Thanks in advance.

[+Cache Hunter D]

When I first got my MeriPlat I had problems like you are describing, but for some reason they seem to have gone away. Either that or I just haven't noticed them anymore. I have upgraded the firmware since then, but the problems resolved themselves before I did that.

 

So I guess basically I'm saying that it just seems to happen sometimes?

[+TotemLake]

>>>In car (sometimes laying on the dash)

 

Depending on your car's position, the satellites could be blocked by the roof behind the unit.

 

>>>Outside with mostly clear skies and the occaisional cloud. (only happened once)

 

There are times when there are so few satellites above the horizon, getting a lock is near impossible. Someone can point you at a program you can download to watch this phenomenon.

 

>>>Outside with a consistant low level cloud cover

 

Satellite signals are in the water frequency. Thus can easily be blocked by dense enough cloud cover. The same is true under broadleafed heavy canopy. It isn't the leafy material blcking you, it's the water.

 

These are just some of the conditions that can adversely affect you. Other factors are proximity to buildings masking your horizon higher than normal. Canyons, valleys, mountainous areas all do the same thing. Proximity of the unit to yourself can do the same thing. Then there is the effect of receiving echo signals.

 

There's more, but you get the idea.

 

I'm told you can compare the signal of the satellite that you're trying to pick up with your GPSr is akin to trying to read a book with a 60 watt bulb that is 20,000 miles up.

 

Cheers!

TL

[+Searching_ut]

You should expect reception difficulty any time something is in the direct line of site path of your GPS antenna and the satellite. Some items like tree branches and leaves tend to absorb some of the signal, but pass some as well so you may still get reception, just not as good. Metal and some other materials completely block it. In you car, you would expect that some satellites wouldn't be directly visible to the receiver. It can often see enough sats to work satisfactory however, and sometimes it works because of reflected signals called multipath.

 

Your reception problems under cloud cover however are not normal. The frequencies selected for GPS are such that clouds, rain, snow etc are virtually transparent.

 

Where moisture can collect however, like a roof, tree leaves etc it can attenuate the signal and cause reception problems so a wet canopy can make your reception worse.