On Sat, 18 Feb 2017 23:13:31 -0800, Jeff Liebermann wrote:
This is a question and initial observation for Jeff Liebermann.
Why me?
Good question. I guess it's because I've seen so much made-up stuff from
the likes of nospam, that you're one of the few people here we can trust.
Does a cellular booster propagate the original cell tower identification?
(Or does the boosted signal have its own cell tower identification number?)
By "booster" are you referring to a bi-directional amplifier like
products from Wilson.
T-mobile gives out a signal booster where you put on unit in the window and
another unit in the middle of the house.
https://support.t-mobile.com/docs/DOC-14947
It's supposed to "boost" the signal.
https://support.t-mobile.com/communi...signal-booster
If so, they repeat exactly the original signals both incoming and
outgoing. What you hear is the tower ID. The device does not
generate any new data or belch a new tower ID.
I think this is the case that the signal booster passes through the
original tower ID since I don't see any *new* tower ids when I hook up the
signal booster. Of course, it could just be that the signal booster isn't
working because the signal strength doesn't get any better either.
However, if you're referring to a Femtocell or similar internet
connected microcellular device, the answer is yes, they do have their
own unique ID.
I do have a femtocell also, and that *does* have its own unique ID which I
have identified already.
https://support.t-mobile.com/communi...g-lte-cellspot
So the question was just about whether the booster generates its own unique
cell id or if it just passes through the cell ID of a tower somewhere in
Santa Cruz or San Jose.
My initial assumption (which needs to be tested) is two fold:
a. It seems the router-connected micro tower has its own unique cell id.
Yep.
b. It seems the booster may simply propagate the "real" cell tower cell id.
Yep.
Does that make sense?
Yep.
Thanks. That made sense.
By the way, long ago you helped me set up a Linksys WRT54G as a wired
extender (yes, you cautioned against it in favor of better solutions).
Do you think it makes a difference if I hook up the femtocell to the wired
extender versus the main router?
How far away do you think the strongest (or nearest) T-mobile cell
tower is located from your test location?
The nearest tower is only a couple of miles away, but consistently I get
connected to towers that are ten and fifteen miles away. They bounce around
as I watch them from the MIT CellTracker app.
Any possibility that one of
your neighbors might have a T-mobile microcell box that you're
hearing? I'm suspicious of the rather strong tower signal.
Without the booster and without the femtocell, I get horrid signal, roughly
minus 90 to minus 105 decibels. With the femtocell, I get minus 60 decibels
consistently. I can even have stronger cellular signal strength than wifi
signal strength, which is amazing.
And, yes, *all* my neighbors have either a booster or a femtocell or they
use WiFi calling (since bad signal is ubiquitous in these hills).
Back of the envelope calculation:
+27dBm Estimated transmit power from the cell site
+10dB My guess of the panel antenna gain
-53dBm Receive signal level from your test.
Path loss = 27 + 10 + 53 = 90dB
Calculating the distance where the path loss would be -90dB at 700MHz:
http://www.proxim.com/products/knowledge-center/calculations/calculations-free-space-loss
is about 0.7 miles or about 4,000 ft. The cell tower would need to be
rather close to your location for that to work. Like I said, I'm
suspicious of what you're measuring.
Thanks for showing me how to do the math to approximate the distance to the
antenna based on the received signal strength indication.
I must not have stated clearly which is that the only time I get minus
sixty decibels is when the femtotower is in place, where it's only a few
feet from my phone.
Otherwise, I get around minus a hundred decibels, which sucks.
+27dBm Estimated transmit power from the cell site
+10dB My guess of the panel antenna gain
-100dBm Receive signal level from your test.
Path loss = 27 + 10 + 100 = 137dB
At 700MHz:
http://www.proxim.com/products/knowledge-center/calculations/calculations-free-space-loss
Puts the antenna at about 2 miles away.
There *are* antennas two miles away (and sometimes I connect to them); so
the math isn't as bad as I thought. I also connect to antennas ten and
fifteen miles away, but that's driving distance, so I'd have to look at the
distance as the crow flies, which could be in the less-than-five-mile
range.