SparkFun Forums

[seulater]

i recently moved, and for circumstances beyond my control (my wife ) will not allow me to use the spare bedroom upstairs for my new computer room / lab. she has me confined to the basement for that.

Normally this would be great, but since i am into all this GPS stuff and there is no window down there i cannot receive a GPS signal.
most of the GPS modules i use are the ones with the built in antenna like the EM-406 so i cannot use a remote antenna.

SOOOoooooo, i was wondering if there is some kind of gizmo out there that is like a remote antenna, so i can put one end outside(the receiver or antenna part) and the other end kinda like some low power transmitter which is more or less an repeater for what is it receiving outside.

then when i use my EM-406 inside it will still work as if it is outside.

[landon]

I think what you are looking for is a GPS re-radiator, but they aren't cheap and in some cases the FCC has ruled them illegal...or you need an experimental license to run one (at least that was as of a year or so ago, the regulations may have changed.) FCC took down wal-mart and gpscity selling GPS re-radiator products.

Still some still either did what they needed to with the FCC or somehow got cleared:

http://mobilegpsonline.com/mgpsos/index ... cts_id=124

[poynting]

I made something like this out of an old active antenna once, and had very good results:

http://www.gartrip.de/antenna.htm

[poynting]

another, with some more picts:

http://bytethebullet.com/geocaching/rer ... ntenna.htm

[seulater]

Huh, i would have thought something like this would be more common. They could be used all over the place where GPS signals get to weak like parking garages, under bridges, inside stores that sell GPS units where no signals are available.

[landon]

It's an odd space in some ways. Some anecdotes:

I worked on vehicle location systems in the Colorado Springs area and we installed on all the military bases around the area as well as in all the fire stations in the city. We had to get special dispensation to run a re-radiator on a military base both from the FCC and from the base frequency managers.

The Air Force Academy applied for and received an experimental license from the FCC to run a reradiator. On Peterson Air Force Base, the fire station is practically on the flight line, and we still haven't installed a reradiator in that station. So, any reradiation near an active airport is really looked at hard.

We also found if we ran a reradiator in a fire station, some reradiators at the time would completely overwhelm a normal GPS...we had to attenuate the signal indoors they were so strong. Again, something else to consider when you put one in.

So, as I said, a couple of anecdotes about reradiators from my experience. I'm not an RF guy and haven't kept up on the FCC stance w/r to reradiators over the last year or so. Perhaps things have loosened up, perhaps not, but it's something to check on before hooking one up.