This is a response from "The Real Bev" brought over from the other thread
so that we can keep the answers together in one related thread.

The "" denotes "Harold Newton", while lack of "" is "The Real Bev".

The repeater (which basically just picks up a weak signal and amplifies it)
has a power supply whose secondary is 12 VDC at 1.5 Amps, which is
*perfect* for a cigarette-lighter adapter, don't you think?

Exactly. Does it have a wall-wart with a USB socket? OTOH, I have a
couple of converters...

The femtocell, which has to be attached to a router, has a power supply
secondary output of 12 VDC at 2.0 Amps - which is also within the range of
a car.

Of course, they work in hotels too, and camping, so, you *could* get away
with it - but I wonder if they could tell?

For the repeater, they might not be able to tell, unless the repeater
itself sends a signal *back* to the tower since I've already seen using the
debugging tools on the Android phone that the repeater just repeats the
*same* tower information to the phone.

Why would they bother? Why would they even care?

That is, the Android debugging tools I've used show clearly that the
repeater itself, does not seem to provide the phone with any other number
but the nearest (strongest) unique tower number.

However, when my Android phone picks up the femtocell, the *unique* number
of the femtocell *is* displayed on the phone (this test can't work on iOS
even though the iOS Apple Apologists "say" it can, sans any proof).

In summary, for the free T-Mobile cellular repeater:
a. The free repeater use 12 volts DC input at 1.5 Amps of current
b. Hence, the repeater could be used in a car, theoretically (I assume)
c. Certainly it could be used camping or at a hotel
d. But would T-Mobile know that you moved it?
e. Maybe not. The repeater just strengthens the local tower strength
f. Does the repeater report back to T-Mobile? I don't know.

In summary, for the free T-Mobile cellular femtocell:
A. The free femtocell uses 12 volts DC input at 2.0 Amps of current
B. But it needs to be connected, via Ethernet cable, to 'something'
C. In a car, I don't know of that 'something' to connect to (do you?)

I have USB and earphone sockets, but no ethernet :-( Does it normally
plug into 110V with a wallwart? I have a converter. Doesn't solve the
ethernet problem, though, which presumes a router :-( Never mind...

You'd think they'd provide a simple cigarette-lighter plug-in unit.
It's to their advantage that you be able to connect with T-Mobile as
often as possible -- otherwise you might choose Verizon. Maybe even a
rechargeable battery-operated unit so I could phone from the ski slope :-)

D. Certainly it could be used camping or at a hotel if you have an AP
E. But would T-Mobile know that you moved it?
F. Probably. The femtocell has a unique tower number & your IP address
G. However, you can change your IP address so, maybe T-Mobile won't notice?
H. But the IP address has a "geolookup" location - which they 'could' see

Perhaps run a VPN on your phone. No idea how practical this is.

Dunno enough about this, but I added sci.electronics.repair because smart
people like Jeff Liebermann know this stuff far better than I do.

All I know is that T-Mobile gave me both, even though they normally only
give you one, because I have a large house and I get my Internet over the
air via WISP which Jeff Liebermann is intimately familiar with, so they
gave me both, for redundancy, for free, with zero deposit required.

I NEED to visit the T-M store.