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Decent RSRQ/RSRP but terrible SINR on external antenna?

olisones

Casual Member
First time poster so hello! This is a bit long winded, but I hope someone might have some ideas...

I have been running a 4G set up with Three for a while, firstly with a B315 with paddles and more recently a B525s-23a in bridge mode as I'm also using an Eero mesh set up.

I decided to get an outdoor antenna as our speeds had dropped quite a lot (from around 25mbps to 8mbps). This was partly due to Three working in the area (which apparently has now stopped without much improvement) I purchased the Poynting 4G-XPOL-A0001 as have placed it around 10ft up on a first floor terrace (so around 25ft all in).

For some reason, I can't seem to get decent SINR numbers, despite the RSRQ/RSRP being okay. Here's a snapshot:

SINR: 3db
RSRQ: -12db
RSRP: -81dBm

I'm now getting around 5 - 8Mbps down and 20Mbps up.

These were taken with LTE H-Monitor.

The odd thing is, when I swap out the XPOL with some 9dBi paddles, I get much better SINR:

SINR: 15db
RSRQ: -10db
RSRP: -85dBm

With the paddles I get about 20Mbps down and 1Mbps up.

I'm currently on Bands 3 + 20. I've taken the router of bridge mode incase this might affect things. The cell tower according to Cell Mapper is about 200 meters away, however this is the opposite side to our property.

I'm flummoxed as to how the smaller paddles get a better connection. I wonder if anyone can help shed some light on this? Do The better upload speeds suggest cell congestion?

Many thanks!
 
Try limiting your router to band 3 alone (Band20 isn't going to do anything for your speed) using LTEHMonitor, this may improve your speeds.
 
Firstly, are you connecting to the same mast, cell and then frequency with both readings? The router should report the CELL_ID value that should be enough to deduce if its the same or different.

[I'm going to assume that you are connected to the same cell in both instances]

The external antenna you have is omni directional, as such it picks up signal from all directions and any gain it provides boosts both the signal you want, and signal you don't want (noise/interference).
Also be aware the antenna gain might be counteracted by the signal loss of the cable and resulting in lower signal levels.

In my opinion the main reason for considering an external antenna would be if your building was constructed of such a material that it blocks a lot of signal (thick sandstone walls etc).
With you being so close to your mast and getting good/great metrics I don't see the need of an external antenna.

What I feel might be happening with your SINR is that your building is actually blocking some of the noise/interference from getting to your router, but by putting the antenna externally you're not blocking the noise anymore, but also not making the signal any higher, making the SINR (R=Ratio!) lower.
 
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Firstly, are you connecting to the same mast, cell and then frequency with both readings? The router should report the CELL_ID value that should be enough to deduce if its the same or different.

[I'm going to assume that you are connected to the same cell in both instances]
Yes, they were on the same mast, cell and frequency for those numbers.

What I feel might be happening with your SINR is that your building is actually blocking some of the noise/interference from getting to your router, but by putting the antenna externally you're not blocking the noise anymore, but also not making the signal any higher, making the SINR (R=Ratio!) lower.
That's very interesting. So in effect the outdoor antenna is a little pointless based on your theory? At the moment (8.30am) I'm getting 28mbps down/18Mbps up, although I imagine this is due to less congestion on the tower?

Also, is there anyway to combine external and internal antennas? It seems the external gives me stronger uploads and the internal gives better downloads. I wonder if there's a 'best of both worlds' scenario?
 
As above, try just forcing B3 alone. Perhaps what is happening with the slow upload is that you've connected to B20 and the primary, and B3 as the secondary when aggregating them.
The primary is always used as the upload frequency (except if there is UL-CA available, which neither Three or the B525 support) so you're limited to whatever the primary can do. For Three B20 has a third less theoretical throughput capacity vs B3 and it covers a wider area/more people, so if it's using B20 as primary then uploads are going to be constrained.

Edit: for the situation you have described, to me it feels like an external antenna isn't required. And no there isn't a way to pick and choose which antenna gets used for TX/RX.
 
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As above, try just forcing B3 alone. Perhaps what is happening with the slow upload is that you've connected to B20 and the primary, and B3 as the secondary when aggregating them.
The primary is always used as the upload frequency (except if there is UL-CA available, which neither Three or the B525 support) so you're limited to whatever the primary can do. For Three B20 has a third less theoretical throughput capacity vs B3 and it covers a wider area/more people, so if it's using B20 as primary then uploads are going to be constrained.

Edit: for the situation you have described an external antenna feels to me that it isn't required. Non there isn't a way to pick and choose which antenna gets used for TX/RX.
Do you know if the B535 supports UL-CA? I can get hold of a model that has bridge mode which might be better?
 
No,/ it doesn't, only more expensive models tend to, and then it requires the network to support and deploy it too (Three don't).
 
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As above, try just forcing B3 alone. Perhaps what is happening with the slow upload is that you've connected to B20 and the primary, and B3 as the secondary when aggregating them.

I’ve been on B3 and speeds are slower than earlier in the day although I guess that is to be expected as the cell gets busier during the day. Currently 16.6 up and 24 down. Wish those were swapped...!

With regards to the outdoor antenna picking up more issues, is it worth just using the Xpol indoors? Presumably it pushes more through than paddles?
 
I wouldn't bother with the external antenna indoors, just use the internal ones or the paddles.
 
With regards to the outdoor antenna picking up more issues, is it worth just using the Xpol indoors? Presumably it pushes more through than paddles?

I'd give it a go. There isn't much science involved with the use on antenna in my experience, it could provide a better signal in the most unlikely place. Its not just a case of pointing it in the direction of the mast, its also beneficial to place it where the signal can bounce around your walls and into the xpol. Try around the sides of chimney breasts, as this is what works for me.
 
I’ve been on B3 and speeds are slower than earlier in the day although I guess that is to be expected as the cell gets busier during the day. Currently 16.6 up and 24 down. Wish those were swapped...!

With regards to the outdoor antenna picking up more issues, is it worth just using the Xpol indoors? Presumably it pushes more through than paddles?
Your speeds do suggest a reasonable load (congestion if you will) on your cell.
24up is good, indicating the router to mast connection is good (and aligns with your metrics) but as you're not getting close to the theoretical speeds with the download something else is limiting that (likely the load on the mast).

What do you understand the purpose of an external antenna? It doesn't push/receive any data itself (that's the modem in the router) rather they're designed to collect the radio signal and feed that back to the modem.

If looking to improve RF metrics (RSRP/SINR/etc) then an antenna with a high gain on the frequencies you wish to use is required. Antennas are specifically tuned/designed to improve sensitivity in those frequencies to deliver higher signal levels to the modem (that includes the signals you want, and signals you don't (noise)). Then any cabling you have between the antenna and modem reduces the gain again (cable loss).

Using paddles might well give a better increase in RF metrics, even if they aren't specified for a particular gain, since there is just centimetres of distance and so minimal loss.
 
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What do you understand the purpose of an external antenna? It doesn't push/receive any data itself (that's the modem in the router) rather they're designed to collect the radio signal and feed that back to the modem.

When I say 'push' I didn't mean data itself, more a cock-eyed description of radio signals..!

I do wonder if the work Three was doing in the area moved users to that specific tower. Just checking now, and I'm getting 21/17 respectively, which considering how it's been I'm pretty pleased with. I'll monitor over the next few days and see how it is.

Thanks for all your advice!
 
Your speeds do suggest a reasonable load (congestion if you will) on your cell.
24up is good, indicating the router to mast connection is good (and aligns with your metrics) but as you're not getting close to the theoretical speeds with the download something else is limiting that (likely the load on the mast).

What do you understand the purpose of an external antenna? It doesn't push/receive any data itself (that's the modem in the router) rather they're designed to collect the radio signal and feed that back to the modem.

If looking to improve RF metrics (RSRP/SINR/etc) then an antenna with a high gain on the frequencies you wish to use is required. Antennas are specifically tuned/designed to improve sensitivity in those frequencies to deliver higher signal levels to the modem (that includes the signals you want, and signals you don't (noise)). Then any cabling you have between the antenna and modem reduces the gain again (cable loss).

Using paddles might well give a better increase in RF metrics, even if they aren't specified for a particular gain, since there is just centimetres of distance and so minimal loss.
Gavin, probably a daft question but why doesn't anyone do a set of high gain rabbit ears 3ft long connected together in an elaborate grid shape that plugs into the router directly?
 
Gavin, probably a daft question but why doesn't anyone do a set of high gain rabbit ears 3ft long connected together in an elaborate grid shape that plugs into the router directly?
Why would they have to be 3ft long? AFAIK bunny ears are generally just a wire that are of a length that is a multiple (division of?) the wavelength of the frequency that they're designed to be used for. You can get longer (15inch?) WiFi ones with higher gain, but I've not seen ones for mobile frequencies.
Also, cosmetics.
 
Because the higher the multiple of the wavelength surely it'd be able to send/receive at a higher SNR? Likewise, I wonder if anyones put a small sat dish behind their router on their desk to see if it does reflect a signal better?
 
Because the higher the multiple of the wavelength surely it'd be able to send/receive at a higher SNR? Likewise, I wonder if anyones put a small sat dish behind their router on their desk to see if it does reflect a signal better?
Tinfoil works a treat, I tried it in a corner with my CPE Pro 2 in a friends house, and it increased their signal by quite a margin.

Luckily I don't need a tinfoil corner at home. Lol

It was just an experiment, as the signal was weak for them, but it did work well.
 
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Because the higher the multiple of the wavelength surely it'd be able to send/receive at a higher SNR? Likewise, I wonder if anyones put a small sat dish behind their router on their desk to see if it does reflect a signal better?
Any gain will gain both the signal, and any interference/noise the same amount, so the SINR will remain the same.
Directional (or shielding/parabolic) are ways to attempt to 'prefer' the signal you want, over the interference/noise signals (assuming the source of noise is not in the same direction as the signal you want).
 
A couple of thoughts on the external antenna. You're using the omni-directional, so a directional may work better (I use the Poynting 4G-XPOL-0002). Also, it's possible the antenna leads may be running close to a source of interference (although this probably only applies if, like me, you have to use unshielded pig-tails which you probably don't as I think your router has SMA connectors). I found that if the pig-tails were near/in my comms cabinet the SINR dropped from 15-20 down to 9-14. The simple act of moving the modem so it was the shielded shotgun cable running near the cabinet resolved it.
 
Hi all. Just some updates - I got hold of a Bridge mode B353-232 router and have been using this without the external omni antenna or without the paddles and it seems to be giving me much better numbers. However, on looking at the B535 with LTE H-Monitor, it seems I only have access to bands 1, 7, 20 and 38. Would there be any reason for this? I seem to be moving between two cell towers so could this be the reason?
 
Sounds like it's a provider supplied unit that has custom firmware which limits the bands (but also enables bridge). The bands that should be available on 'stock' B535s are 1/3/7/8/20/28/32/38.

If you don't have band 3 (or band 32) then that's not going to be great for use with Three. I suspect the reason you're seeing better numbers (presumably the signal metrics, rather than speeds?) is that you're connected to B20, which penetrates more easily than higher frequencies, whereas before it was B3.
 
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