In article Eric Greenwell writes:
Alan wrote:
On the ground, where there are obstacles, that is true. To an
airborne receiver, the range is much farther.

And yet, I can have good service on the ground, but poor or no service
in the air, over the same area. It's not about obstacles, but antenna
patterns, power, and how the system handles a phone that is reaching
multiple towers.

My point exactly.

In the air, your phone hears multiple cell transmitters on each frequency.
It may have difficulty finding a channel where it can clearly hear the
control information.

On the ground, those obstacles limit the number of cell towers your phone
can hear, so it has no trouble finding a clean channel.


Don't be sure about that low power -- the directional antennas have a
fair amount of gain. The FCC allows 500 watts per channel of
effective radiated power, but 100 watts is a more common figure.
(See: http://www.fcc.gov/cgb/consumerfacts/rfexposure.html ).

From the article:

"the majority of cellular or PCS cell sites in urban and suburban areas
operate at an ERP of 100 watts per channel or less".

The "or less" is important, as a small cell doesn't require much power.
The ERP is obtained with directional antennas, so while it might seem
high, the vertical angle coverage is very shallow.

However, the vertical angle is not that shallow. Even an antenna with a
half power beamwidth extending up only 5 degrees puts that half power level
above 3000 feet at 7 miles out, a very easy range given the lack of
obstacles.

Directional antennas don't completely cut off outside the half power
beamwidth.

Your explanation also doesn't explain why when the cellphone doesn't work
while standing on the mountain top next to the suburban area, walking behind
a building to shield the phone from the view of so many cell towers causes it
to start working. The angles from the cell towers don't change.

Alan
wa6azp