Report from the cruise to Mexico

[Mychaela Falconia]

Hello FreeCalypso community,

I am back from my little cruise vacation, and here is my report on GSM
services:

* When we were in Cabo San Lucas and in Puerto Vallarta (the third
planned port call in Mazatlan got canceled because of an aviation
accident: a small plane crashed into the navigation channel which we
would have to go through to get to Mazatlan port), my Pirelli DP-L10
phone running its original fw successfully picked up GSM network
334-020 (Mexican Telcel), roaming on it with my legacy T-Mobile USA
SIM.  I was able to observe its operation using rvtdump and the
firmware's built-in engineering mode menu (*36446337464#), and the
neighbor cell list looked a lot healthier than what we get on T-Mobile
USA running in the guard bands - thus I am hoping to have a good
experience when I go back to Mexico to explore this network more
thoroughly (see below).

* While we were at sea away from USA and Mexican shores, there was a
ship-generated GSM signal.  Initially as we sailed away from Los Angeles
my Pirelli DP-L10 picked up a signal on ARFCN 512 (no way of knowing
if it was DCS or PCS, see below), with MCC-MNC set to 001-001!  It was
certainly strange to see the network broadcast with MCC=001 (meaning
test) rather than 901 or 999, and I couldn't tell if the band was DCS
or PCS because I didn't have my laptop handy to look at the trace,
thus I only saw what the *36446337464# menu showed me.  However, this
ship-generated GSM signal later changed to PCS ARFCN 517 (this time I
knew it was PCS because I connected my laptop and ran rvtdump), and
the broadcast MCC-MNC changed to 901-018, a proper network ID for
ship-based maritime GSM.  My phone stayed in its "Limited service"
state while it picked up this network: it camped on the cell, but had
no TMSI, and I reason that this maritime roaming network was not
accepting registration from my legacy T-Mobile USA SIM - lack of the
needed roaming agreement perhaps?  Not accepting that registration was
for the best - if it had been successful, roaming charges would have
been outrageous.

I did not attempt further exploration for two reasons:

1) The group we were with (my partner and I did not go on this cruise
by ourselves as a couple, we were with a big group doing other
activities that would be too far OT for this list) had the entire
cruise week jam-packed with activities, and I had no spare time left
unfortunately for GSM exploration.

2) Our stateroom was in the interior of the ship, and the signal was
extremely weak inside after passing through multiple walls and other
rooms etc.  Inside our cabin was the only place where I could easily
connect my Pirelli phone to my laptop, but all those walls absorbed
not only shore-originating signals, but also the ship's own GSM signal
- inside the room the phone picked up nothing at all!

Going forward, I am hoping to make more frequent visits to Mexico by
land border crossing, i.e., driving across the border in my car and
hanging out in Baja California towns (Tijuana, Rosarito, Ensenada)
that are close to my San Diego home base.  My next visit to Tijuana
will likely be combined with a follow-up appointment with the surgeon
who did my SRS a year and 8 months ago, and I am hoping to schedule it
some time in the next month or two.  I really hope that I can get a
new native Mexican Telcel SIM (the one I got at the time of my surgery
has almost certainly been deactivated after a year and a half of
non-use), and that current-issue Telcel SIMs are still officially
2G-supported as in "Compatible con GSM, 3G y 4G" like that last one
was.

In terms of other digital souvenirs from the cruise, I got some photos
of me interacting with dolphins in a pool in Puerto Vallarta, and a
short video my partner captured of me emerging from the Riptide water
slide aboard the Navigator.  I may post them a little later.

Hasta la Victoria, Siempre,
Mychaela aka The Mother