On Thu, 25 Jan 2018 19:56:36 +0000 (UTC), Harold Newton
wrote:
Agreed that Jeff is usually on the money
Hardly. I probably make more mistakes than others. The difference is
that I usually admit being wrong. Feel free to trust me, but it pays
to verify.
and that you have a point which is
that the femtocell comes with a GPS contraption, which you only use during
the initial setup.
You can see the stick-on GPS unit bottom right in the photo below.
https://u.cubeupload.com/RU3rGl.jpg
Why did they ask me to plug that GPS unit in *only* during setup?
Good question. It didn't take much for me to find out what happens if
one doesn't have a GPS signal with a Verizon nanocellular box:
https://www.verizonwireless.com/accessories/samsung-network-extender-scs-2u01/
This is 3G only, no LTE. From a cold start, it takes 15-30 minutes
for the unit to boot to the point where it will accept calls. If the
GPS has a good view of the sky, 10 minutes is about the fastest I've
seen. If you have a partial or marginal view (as most of my customers
do), much longer.
If I take a working unit (all lights blue), and pull the plug on the
external GPS antenna connector, it remains functional for about 20
minutes. It then starts flashing the GPS lock light and will not
accept or receive calls. After loss of lock, if I plug the antenna
back in, it locks faster than a cold start. I didn't time this, but
my guess(tm) is about half.
If I take a working unit (all lights blue), and remove power at the
wall wart, it will recover lock in about 5 minutes. However, if I
leave it unplugged for over 15 minutes, it will take 10-30 minutes, as
in the initial cold boot, to lock again.
So, my guess(tm) is that:
1. There is no non-volatile storage in the unit to store the GPS
position and to provide a faster cold lock.
2. There is a BFC (big fat capacitor) inside to help deal with power
outages.
3. Without a GPS signal, it will make phone calls for about 15-20
minutes before it quits, after which it will refuse to make or accept
phone calls.
Not all devices are created equal. As micro/nano/pico/femto/extender
cellular devices go, this Verizon unit is rather old. The T-Mobile
devices are much newer and may have improvements in the GPS area, such
as battery, supercap, or NVRAM backup. Dunno. Testing is easy
enough. Set it up so it works, cover the GPS antenna, and wait for
the device to complain.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558