[Captivate General] MikalCarbine:
Lol @ Apple, although they definitely screwed their design up, I don't think the outer metal shell is the antenna itself, it may be the antenna grounding plane or the antenna (typically some form of a coaxial wire) is wrapped around the internal of the phone, following that outer metal shell. I didn't follow the whole debacle to know any specifics.

What you say about the back plate connection makes sense. I myself have observed that without my back plate my signal is actually better, doesn't make much sense does it? The only thing I could think of is that with the back plating pads being oxidized/covered in some material, the back plating actually acts as an insulator to the antenna in the phone. This is pure speculation however.

As for results... I think looking into an external antenna through a connector like the one I linked above would be key.

However for dealing with the grounding points on the back plane, that will have to involve some empirical user testing and data, which up to this point has not been consistent. Scientifically it only makes sense that improving this grounding plane would help make up any short falls in the antenna design. This is assuming the cell phone antenna is a monopole (a single wire or pole that transmits but requires an equal or like ground plane to operate correctly). The whole deal with taking the battery cover off and the signal increasing is boggling, I think we should still keep testing though. I currently live in a dead zone so any testing I do personally I feel won't be accurate. I will be able to do some testing later this week in a decent signal zone and I'll report my results then

Here are few ideas for testing in the mean time:

-Try folding a piece of tin foil a few times, thin enough so it will fit between the battery cover and the phone. Make sure it is touching the two ground points in question. This would be a good test to conduct with the battery cover back on and when it's off. You may want to use a little sand paper on the areas of the tin foil that will be touching the two grounding points

-Use alligator clips from the grounding points to a larger piece of tin foil or metal to try to increase the ground plane.

-Ideally, solder two short wires (one from each grounding point, alligator clips may work) to a block of copper or similar metal object to aid in grounding the device. I;m not too sure how well kitchen tin foils acts as a ground haha

-For now I'd hold back from connecting your phone to your car as a grounding plane. The noise from the car's alternator might not play well with these two points and the phone

I'd really like to stress that number of satellites and lock speed isn't too important. As we've seen from the 100,000 GPS threads, simply playing with some software settings can drastically decrease the lock time and help with the total # of satellites found. I understand this mod does help with these two issues but I think the largest issue is "Does it help MAINTAIN a GPS lock during rides, performing similarly to other cellphone gps devices" Be sure to record your results if you do end up doing any of these experiments. Try to take a drive and see how well the GPS stays locked. A comparison of battery plate cleaning vs tin foil mod performance would be nice