Walt_Felix

I agree, several near me wouldn't meet the "minimum vertical fall of 5 feet and a continuous flow of water" requirement of that catory. There should be separate catory for dams.

I was just looking for this category and I'm surprised it isn't already one. There are somthing like 10 dams within a few miles of me.

Yes, many cars now have heated windshields which can prevent satisfactory reception. An external antenna is almost mandatory in such case. If your GPS has an antenna port, it's as simple as using an external roof mount antenna. If you GPS doesn't, a re-radiating antenna will help. Re-radiating antennas consists of 2 components, a roof mount receiving antenna and an internal transmitting antenna. Receiving antenna has internal signal amplifier so requires power. Most often they plug into a 12v power source though I've seen a few that are battery powered. The amplified signal is transferred by a cable to the transmitting antenna inside the vehicle which "radiates" the signal to the antenna of GPS. Even in vehicles without the windshield in question, because it's an amplified antenna, one can be used to increase overall signal strength.