A high gain directional antenna on a CDMA phone
would extend battery life since the transmitter
would not have to run at as high a power level as
with an omnidirectional antenna. Good for fixed
operation.
Yes, that has been my experience, too.
Before that, I could hit a tower 40 miles away with an analog bag phone and a directional antenna, and did so often, working on oil rigs.
Digital was a pain because it was designed to work where there are sidewalks (close in), and I had to get a booster for the CDMA phone, adapters and hook that to the antenna. Without it the battery would die in no time, looking for signal.
The results were seldom as good as with the analog phone--more dropped calls or 'no service' moments, even if connections had less static.
Now AT&T has bought out my carrier and I have to change phones (GSM, now) and equipment yet again--and have it work the first time.