[pct-l] SPOT is not just a GPS

[Sean Nordeen]

I'm sorry, but as an engineer I can't keep reading some of the comments about this device and comparring it to a GPS receiver and keep quiet.  Stop comparing them.  No, adding a better GPS chip to a SPOT device will not improve it.

Of course a GPS receiver will work better.  A GPS receiver only has to receive transmissions from a couple of satellites above that do not even know that any receivers exist.  A spot device has to transmit (broadcast/send) a signal to a satellite.  A satellite broadcasts with a much higher power level then a tiny little SPOT device with larger and better matched antennas.  Due to the small antenna size and low power of a SPOT, it has more trouble transmitting through poor overhead coverage and line of site to get a signal to the satellite with enough signal quality for the satellite to recognize the message.  The satellite network that SPOT uses also has a few holes in it's coverage that hopefully will be fixed in the future.

When a GPS receiver fails to work, it isn't able to receive a signal from enough satellites to get a fix.  When a SPOT fails to work, it isn't able to get a find a satellite or fails to transmit a signal to it with significant strength and quality to be recognized. And less often, it will occasionally transmit fine but miss the response back from the satellite.

Devices such as SPOT will improve in the future as better low power transmitter technology comes around and more satellites are put in orbit.  But currently, you should not think that having a SPOT will allow you to take more risks then you normally would since it isn't reliable enough to soley rely on it.  But it is certainly better then nothing.  So carry one if it helps calm the family, but don't go crazy just because you have one.

-Sean