mobile phones

Michael Ash wrote:

My understanding is that the major problem with cell phones on GA
craft was simply that the old-style cell networks couldn't handle them. An
active cell phone in the air would be within range of a bunch of different
towers which caused confusion in the network, since it was built on the
assumption that the ground would limit your line of sight so that you
would only be in range of two or three towers at a time.


There are also interference issues with AIRCRAFT SYSTEMS.

At an FAA DER Seminar a couple of years ago, they pointed out that
some "phones" would transmit spurrious signals off their frequency
that could couple with antenna cables (shielded or not), and interfere
with aircraft navigation systems (mainly VOR). It's not as simple as
many think (and I'm an aero guy, not an electron guy, so I won't
pretend to really understand).

I was on a test flight where we determined that our telemetry
transmitter COMPLETELY wiped out the reception of our $25,000.00
Ashtech GPS receiver.

Older phones (and older aircraft equipment) tend to wander off of
their original specifications. While most gliders don't rely on VOR,
but rather GPS for navigation (some of us use windows, charts and
eyeballs), the interference from "phones" may not be as much an issue
-- but we've shown that it can be.

The FAA guy indicated that a particular Samsung phone (now off the
market, I'm told) could completely trash com and nav functions on an
airlner type "ship." Autopilots have been affected, too. "Hardening"
transport (airline) aircraft systems (for new models) is a serious
consideration in this modern world of emitters, but always needs to be
balanced against cost, weight and performance. Also, putting small
"pico" cells (a small cell "tower") ONBOARD the aircraft seems to
help: the closer tower causes the phone to shift into a lower power
consumption mode (i.e., lower transmit power, which translates into
less interference).

Caution is advised. It would be a shame if your 1000k log was trashed
when you called Mom to tell her you finally did it...

-Pete
#309