swwifty wrote: ↑Fri May 31, 2019 9:23 am
If your mobile device (in this case your LTE Modem) hands off to another tower you will see that switch. I'd recommend using the 'at!lteinfo' command to see all the cells that are in range.
Yep, I'm using it to keep an eye on them already. There are generally 3-5 other towers chatting away at lower signal strengths at any moment in time here, at ground level and even at the 2nd story level.
swwifty wrote: ↑Fri May 31, 2019 9:23 am
Keep in mind that even though we use the term "towers" each physical tower has many different "cells" on it that are typically sectorized. Keep a close on the PCI numbers in the at!lteinfo command. Typically cells that are on the same tower have PCI numbers that are very close to each other. If the numbers are far apart in range, typically you are seeing a signal from a cell that is mounted on a different physical tower, or perhaps a different sector that is pointing away from you. Self-interference is the one of biggest challenges in LTE.
Correct, correct, correct and correct.
I just wish they'd show the base 10 Cell ID (also close in value for a given tower, typically) instead of the Physical Cell ID for each of those other cells, because the last 3 of Cell ID is what I have committed to memory and it is what shows in the status results. Would have been nice if it was consistent or showed both on each screen.
swwifty wrote: ↑Fri May 31, 2019 9:23 am
I suspect that you might have the tower numbers reversed. If you see the signal increase when you move the antenna 180 degrees that is a sign that the signal is in fact coming from a different direction. The signals don't scatter as much as you'd suspect. Read about multipath, and you'll see what I mean. When they scatter they tend to degrade or cancel each other out in phase and make the signal really weak.
You may not have read above that I've been to each of these towers, so I know which one is which. There isn't any confusion there. I suspect that my environment is closer to what you reported you saw at the state park vs what you see at your base location. I just have a lot of towers bouncing things around.
swwifty wrote: ↑Fri May 31, 2019 9:23 am
Remember the dBM scale is logarithmic. If you see a +3dBm increase in signal thats a signal twice as strong! 10dbm is 10x stronger!
Correct. More on that further down.
swwifty wrote: ↑Fri May 31, 2019 9:23 am
I've heard of boosters causing issues with other LTE devices. I have a feeling that your booster might be taking the signal your modem is connecting too and amplifying it, then sending it back out. I'd highly recommend trying these tests at your house with the booster off to rule that out as causing any issues. Those boosters can cause some serious havoc on RF signals.
Definitely a good thing to consider, but not the case in this situation. This booster isn't like all the analog systems on the market. This one is digital and only boosts what it needs to for the phones connected to it from a single provider (in this case, T-Mobile), and only boosts to the degree needed based on the relative location of the two units (they talk to each other over a 5 GHz system, but not 802.11, for some reason).
Where it might come into play is if the AT&T frequency matches one of the few T-Mobile frequencies that the booster supports and if my antennas are close enough to the booster unit that creates the cellular bubble. This would cause similar interference to another tower sharing frequencies, except this "tower" is very close. The bands in common between AT&T, T-Mobile and the booster are bands 2 and 4.
I've done some testing with the booster off and on and haven't noticed a difference in stats, but it is always in the back of my mind that it is theoretically possible, so I'll continue to do A/B testing with the booster on/off. What I haven't done yet is to test it with one of the T-Mobile LTE phones downloading something. That will be a good test. No T-Mobile LTE phones were at home during my initial deck testing and my HSPA+ phone wasn't actively doing much.
I'm getting an LTE phone in another month or so. If I have to chose between reasonable T-Mobile signals in the house without the booster or great signals with the booster, I'll choose the former in exchange for better internet with the LTE modem and external antennas. Right now, with my HSPA+ phone, I can barely use it in the house without the booster on.
The other variable is that the bubble created generally ends at the unit by the window. If I mount the antennas on the opposite side of the window unit from the booster coverage unit, it should be outside the bubble and not be impacted much, *if* it can be impacted at all.
swwifty wrote: ↑Fri May 31, 2019 9:23 am
If you are having issues with signal through glass it more than likely has some coating, or its possible the bug screen on the outside is a metal mesh and killing the RF signal. I've experienced and learned this the hard way before.
No bug screen. What is interesting is if I slide the other half of the window open that does have a bug screen and lean the unit against the bug screen, it gets a better signal (as does my cell phone, directly). The glass attenuates the signal more than the bug screen. I just found it interesting that having the unit touch the glass makes a big difference in signal strength and end results.
Now, I have done some other testing today. I took the flat panel antennas and my rig to one of the towers and tested a couple blocks away from the tower with a clear line of sight. The antennas do have a better signal with them facing toward the tower than away. They were good either way, but still better with the antennas facing forward. RSRP values were about 10 times stronger forward than reverse for the higher frequency bands (1900 and 2300) and about 4 times stronger for lower frequencies (700). That all makes sense and does confirm that the antennas aren't pointing the wrong way inside the cases.
That also means that I'm getting better signals on my deck by pointing away due to the signals bouncing back from the opposite directions. Although highly variable, it seems pretty wild to get a high test score of 75 Mbps download from a directional antenna picking up the signal from the opposite direction of the tower!
