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Forcing Cell Selection

sixtocks

Casual Member
I am fortunate enough to have direct line of sight to two separate cell towers.

Unfortunately, the nearby one (~250m) has its cells pointing in inconvenient locations. I sit on the overlap on the edges between two of them, which seems to mean I get a very strong signal but the throughput is poor and variable. I tested this hypothesis by wandering up to it and downloading things with my phone. Standing directly between the tower and my home was poor, move round a few metres left or right so I'm more on-axis with one of the cells, and it's significantly better.

The further one (~750m) appears to have a cell pointed in a more convenient direction. I'd like to try this one to see if there's much improvement. Unfortunately, because the nearby tower is so ... nearby, this is what the router locks on to without fail.

Any suggestions for how I can make use of the more remote tower, short of bringing forth the destruction of the close one by starting a rumour that it has covid-causing 5G installed?

As an aside, I assume (both being Band 3) that they operate on the same frequency - would this just result in massive interference from the local tower anyway, even if I could specify a connection to the far one?
 
In your testing you need to be 100% certain that you're still connected to the same Cell for each test. You say you walked around testing other locations but unless you noted which cell you were connected to at the time and it was always the same, and is the one you connect to at home, then the testing isn't valid - different cells and masts have different capacity/load/technology deployed.

I believe only Mikrotik routers have the ability to lock to a cell. While their router software is very configurable, it's not very user friendly for novices as a lot of the more technical parts don't have a UI, but rather use commandline commands

Another option could be to try with a directional antenna pointing towards the mast you want to use. Directional antennas, as their name implies, focus their gain in the direction they're pointing to, with signals coming from other directions being of less gain. The theory being that the gain from the directed mast would overpower the less gain of a mast off-axis, and trick the router to using the one you actually want.
There are no guarantees though.
 
I used Network Signal Info on my phone to monitor the cells, and made sure that I was doing a sensible test. It'd flip between xxxx09 and xxxx10 depending which one I was in front of. I can get either of those back home depending on the router orientation, and both are a bit pants!

I'll try a directional antenna. I was concerned that the sheer proximity of the nearby tower would still power through the directional gain and cause the router to select the 'wrong' one.

My router has two antennas. Would I be able to realistically use a single external directional antenna (not MIMO?) to work out whether this was going to work or not?

Edit: I still get a usable connection after switching antenna selection to combo internal/external with no external antennas connected, so it seems a single antenna works fine.
 
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I had this issue with a neighbour, it was a shared Three/EE tower and despite being a mile closer to the mast than my house and having better line of sight his downloads were poor and well below mine. Fixed it finally by swapping to EE as their antenna orientation on the mast suited his position better
 
I'll try a directional antenna. I was concerned that the sheer proximity of the nearby tower would still power through the directional gain and cause the router to select the 'wrong' one.
It might do, hence no guarantees!

My router has two antennas. Would I be able to realistically use a single external directional antenna (not MIMO?) to work out whether this was going to work or not?

Edit: I still get a usable connection after switching antenna selection to combo internal/external with no external antennas connected, so it seems a single antenna works fine.
You don't say what router you currently have, but I believe one antenna would work fine (Huawei documentation often says if connecting a single antenna, use of the specific external ports). Though if you're getting an antenna to try it, might as well get a MIMO one - with a single one you'll likely be limiting the speeds to SISO (halving the theoretical speeds of 2x2 MIMO) so while it might prove the possibility of persuading your router to connect to a mast that you want it to, it may limit your possible speeds.
 
I have ordered a directional MIMO panel antenna, so we'll see what that does when it gets here.

Unfortunately, I have an irrepressible need to fiddle with things I barely understand.

I figured I'd try to get some kind of clue as to how directionality might help by sticking the router in a (fairly shallow - 4" or so, it's what I had!) tinfoil-lined box. Router being positioned at the back of the box parallel to the surface. The assumption here is the tinfoil would attenuate everything not coming from the front.

I couldn't get it to focus on the distant cell, but it had some interesting effects on the signal from the near one. The RSRP value improved by 7-9dB which I was not expecting. Based on a bit of googling, the RSRP considers interference from other cells, so the tinfoil could be successfully reducing that?

It changes fairly significantly on rotating or moving the box, so there is some kind of focus going on. Oddly, the highest RSRP is reported when the box is angled a little away from the tower.

Subjectively, the connection downstream seems more stable (higher downstream, and less fluctuation when looking at a graph of throughput over time) despite little to no movement in the reported SINR or RSRQ values. Upstream has dropped by half in comparison.

If the antenna can be a better version of this box I'll be quite happy indeed. If it can't, well, I'll use the box!
 
RSRP is power. RSRQ considers interference (uses SINR as part of its calculation).
Most likely you're reflecting the signal of your mast so your router is reporting higher power (sees more of the signal).
I can't explain uplink dropping speed though.
 
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There's been delays in acquiring the panel antenna, but I did get an inexpensive yagi antenna from ebay. A real one, not a china special. Only covers B3 though, but I figured it'd let me figure out if I can access the remote tower.

And the answer is ... not really. There is one specific position at which it'll lock on to the remote cell, but the signal is pretty weak and in literally any other angle it'll jump back to the closer cells.

I went scouting with cellmapper on my phone to generate some additional data and map out the boundaries. The cells over there are also angled differently to I first thought - I'm on the edge of that one too. It seems like Three have very deliberately decided to miss me with every cell they have in the local area.

Debating whether to cancel the panel antenna order, as I'm not sure that it'll do anything useful with what I have available to me here. Using a combination of an internal antenna and the Yagi I get some marginal improvements (in terms of SINR) and throughput appears to be more consistent (not increased - just less variable) over an extended test.

Somewhat impressed that combining the directional and internal omni-directional antennas actually seems to do something useful.
 
Well, the experiment is complete, so here's a write-up to maybe save other people the effort in the future if they happen to stumble across this post.

I started off with this situation:
  • My signal is strong because I am close to a tower
  • The signal quality (SINR) is pants, because I'm on the overlap of two cells on that tower
  • There is a tower (well, top of a building) much further away that I also have line of sight to
The drive/assumptions behind all this arsing about:
  • When the SINR is higher, my internet will be faster. This works for my phone, so should be true for the router?
  • My router much prefers the nearby cells. Maybe the signal from the tower further away is better, and a directional antenna would let me use it?
  • Maybe a directional antenna can eliminate some of the noise from the nearby cells and also improve my internet?
So, I acquired:
  • A (highly) directional Yagi antenna working on a narrow frequency range (B3 only)
  • A fairly standard directional panel antenna that covered all the LTE frequencies
What I found out:
  • The router, if simply positioned on a window sill aimed roughly at the cell tower, gives a poor quality signal.
  • The Yagi could focus on the far cell, if positioned very carefully. The strength of signal from the nearby cell (and reflections, I assume) would cause the router to select the near cell even with the antenna pointing entirely the wrong way.
  • Performance from the far cell was not what I hoped. I am also on the edge of that, so it's the exact same situation as the one nearby but with a lot more attenuation.
  • Using the Yagi's directionality did not significantly improve the SINR from the nearby tower. In fact, better stats were received when NOT pointing directly at the cell's antenna
  • Using both the Yagi and one of the internal antennas appeared to give a more stable signal (marginally higher SINR with less fluctuations). The impact on actual throughput was negligible though.
  • Regardless, I acquired the panel antenna. This is directional and MIMO, which could have had benefits over a singular Yagi.
  • The directional panel antenna performed worse than the internal antennas on the router, both in terms of signal stats (SINR, RSRQ) and in measuring throughput. I spent a few hours fiddling with positioning and then carefully packed it back up and organised a return. There was no promising signs from this.
  • None of these actually out-performed the router as a stand-alone unit, when it is placed in the one 'special' location I have identified for it (and I spent a LOT of time trying different locations for this thing). Based on how twitchy it is about the positioning, I think that it is mostly running off of reflections in this location. But it works well.
  • Even a poor quality signal performs a lot better than I thought - I was achieving speeds of 12-20MBit or so with a SINR in the negatives.
And my conclusions from all this:
  • An antenna (directional or otherwise) is probably only really useful if the signal is pretty weak.
  • If the signal is strong, but with poor metrics (as mine is), then an antenna won't do anything to help.
  • Radio waves do really weird things. They bounce around everywhere, and sod knows what kind of path that the ones feeding my router are actually taking. Direct line of sight actually provides a *worse* quality signal for me.
  • The environment changes almost minute-to-minute, so comparing things is difficult if the changes are minor. And if the changes are so minor that environmental differences outweigh them, then the changes aren't worth making.
  • The internals of 4G routers are actually pretty good at making good sense of complete crap and should not be underestimated.
  • Annoying as it is to get a pretty poor signal from a tower I can probably hit with a well-thrown rock, I simply can't beat physics.
So, I'm back to where I was 10 days or so ago, except now I know there's no magic piece of tech I can plug in to suddenly make everything awesome.


To anyone reading this because you're searching the internet trying to find out if buying an antenna will make your internet better, and your situation is close to mine: it probably won't - save your time and money. Try fiddling with the location of your router instead. It's weird, but mine works best when its held vertically with some blu-tack in the corner of a window.
 
Well, the experiment is complete, so here's a write-up to maybe save other people the effort in the future if they happen to stumble across this post.

I started off with this situation:
  • My signal is strong because I am close to a tower
  • The signal quality (SINR) is pants, because I'm on the overlap of two cells on that tower
  • There is a tower (well, top of a building) much further away that I also have line of sight to
The drive/assumptions behind all this arsing about:
  • When the SINR is higher, my internet will be faster. This works for my phone, so should be true for the router?
  • My router much prefers the nearby cells. Maybe the signal from the tower further away is better, and a directional antenna would let me use it?
  • Maybe a directional antenna can eliminate some of the noise from the nearby cells and also improve my internet?
So, I acquired:
  • A (highly) directional Yagi antenna working on a narrow frequency range (B3 only)
  • A fairly standard directional panel antenna that covered all the LTE frequencies
What I found out:
  • The router, if simply positioned on a window sill aimed roughly at the cell tower, gives a poor quality signal.
  • The Yagi could focus on the far cell, if positioned very carefully. The strength of signal from the nearby cell (and reflections, I assume) would cause the router to select the near cell even with the antenna pointing entirely the wrong way.
  • Performance from the far cell was not what I hoped. I am also on the edge of that, so it's the exact same situation as the one nearby but with a lot more attenuation.
  • Using the Yagi's directionality did not significantly improve the SINR from the nearby tower. In fact, better stats were received when NOT pointing directly at the cell's antenna
  • Using both the Yagi and one of the internal antennas appeared to give a more stable signal (marginally higher SINR with less fluctuations). The impact on actual throughput was negligible though.
  • Regardless, I acquired the panel antenna. This is directional and MIMO, which could have had benefits over a singular Yagi.
  • The directional panel antenna performed worse than the internal antennas on the router, both in terms of signal stats (SINR, RSRQ) and in measuring throughput. I spent a few hours fiddling with positioning and then carefully packed it back up and organised a return. There was no promising signs from this.
  • None of these actually out-performed the router as a stand-alone unit, when it is placed in the one 'special' location I have identified for it (and I spent a LOT of time trying different locations for this thing). Based on how twitchy it is about the positioning, I think that it is mostly running off of reflections in this location. But it works well.
  • Even a poor quality signal performs a lot better than I thought - I was achieving speeds of 12-20MBit or so with a SINR in the negatives.
And my conclusions from all this:
  • An antenna (directional or otherwise) is probably only really useful if the signal is pretty weak.
  • If the signal is strong, but with poor metrics (as mine is), then an antenna won't do anything to help.
  • Radio waves do really weird things. They bounce around everywhere, and sod knows what kind of path that the ones feeding my router are actually taking. Direct line of sight actually provides a *worse* quality signal for me.
  • The environment changes almost minute-to-minute, so comparing things is difficult if the changes are minor. And if the changes are so minor that environmental differences outweigh them, then the changes aren't worth making.
  • The internals of 4G routers are actually pretty good at making good sense of complete crap and should not be underestimated.
  • Annoying as it is to get a pretty poor signal from a tower I can probably hit with a well-thrown rock, I simply can't beat physics.
So, I'm back to where I was 10 days or so ago, except now I know there's no magic piece of tech I can plug in to suddenly make everything awesome.


To anyone reading this because you're searching the internet trying to find out if buying an antenna will make your internet better, and your situation is close to mine: it probably won't - save your time and money. Try fiddling with the location of your router instead. It's weird, but mine works best when its held vertically with some blu-tack in the corner of a window.
Very comprehensive post of you results there sixtocks, I had the same results a while back when trying an external antenna.

The external antenna for me actually made things worse, it wasn't a directional but omnidirectional.

I couldn't agree more on how well the internal antennas deal with pulling in signals.

I have the Huawei CPE Pro 2 now and it's been the best so far for me at pulling in signals.

I do agree that reflection has a lot to do with things too, as I've mentioned in previous posts how I've tried the router everywhere under the sun, but it works best in a centrally located corner, not even sitting the router at the windows can better the corner position. Even moving it an inch to a couple of inches can make a huge difference.

PS I'm sure there will be many readers, of whom I include myself, will still have to try external antennas themselves no matter what they read, only to be disappointed.

I'm a little more inclined to pay attention to posts these days though, now I'm older and wiser. (Older yes, wiser probably not)

Anyway, good to read your experience with an external antenna and I'm sure it will be of interest for others wishing to try external antennas too. (y) :giggle:
 
Last edited:
Ive found that SINR in my case is always worse with the routers own internal intennas and the various antennas ive used have been of benefit (ground plane and two omni directional ones from poynting and panorama).
Like you though it really is a case of playing about it with a lot as even the smallest movement can cause wild variants - i find much better "speeds" when I aim the antennas downwards slightly at my flat roof as clearly the signal is bouncing off that. If I set them up with the best line of sight style stuff to the tower then they are not so effective.
Ive yet to try a Yagi antenna but I dont think i'll bother as they wont be so easy to mount for my setup.
 
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