Spectrum Analyzer

GhostShow

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Hi all,

Is there anyone in the Joburg to Vereeniging area that has a Spectrum Analyzer that they might be willing to hire out or let me buy them a beer to just come look at the rain signal at a friends house? With a Mikrotik mANT-LTE omni antenna the signal stats are still
RSRP: -88dBm
RSRQ: -13.5dB
SINR: -1 - 0 dB.

From the RSRQ value the connection should be ok, won't be getting 30Mbps but at least 7-10. Yet my friends only get 1Mbps, the noise seems to be incredibly high for the corresponding RSRP.
 

jbroo

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Jun 12, 2020
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Check your RSSI value. A high RSSI value (e.g. -50) with poor values for the other stats would indicate general noise being picked up by the antenna. It's got to filter that noise and get the usable signal out of it. For reference, I have an SINR of 0 to 2 and I can get 15-30 mbps downstream in the middle of the night (because there is no congestion).

My stats for reference:
1628003894564.png

Is your friend maybe just connected to a congested cell?
 

jbroo

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From this very helpful site: https://wiki.teltonika-networks.com/view/Mobile_Signal_Strength_Recommendations

RSSI for LTE is a calculated from several other signal related measurements: RSSI = wideband power = noise + serving cell power + interference power. For example, a 4G LTE modem might report an RSSI of -68 dBm, but:

RSRP = -102 dBm

RSRQ = -16 dB

SINR = -1.8 dB


In this case, the signal quality is actually very poor. This could be due to the device being some distance away from the LTE transmitter. It’s also possible that something is interfering with the signal, such as a building or other obstructions between the device and the tower.
 

Nurple Derple

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Hi all,

Is there anyone in the Joburg to Vereeniging area that has a Spectrum Analyzer that they might be willing to hire out or let me buy them a beer to just come look at the rain signal at a friends house? With a Mikrotik mANT-LTE omni antenna the signal stats are still
RSRP: -88dBm
RSRQ: -13.5dB
SINR: -1 - 0 dB.

From the RSRQ value the connection should be ok, won't be getting 30Mbps but at least 7-10. Yet my friends only get 1Mbps, the noise seems to be incredibly high for the corresponding RSRP.
Tell your friend to contact rain customer service. Had a Technician call me and found out that 2 of the towers newer me were like 97% utilisation. Luckily for me a further away tower was at 60% utilisation which improved my speeds
 

GhostShow

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Messages
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The utilization is 70% but the one tower 1.55km away is down more than up. But still on the B38 band the SINR is good, but then the tower is like 2.75km away
 

GhostShow

Active Member
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Apr 4, 2020
Messages
81
From this very helpful site: https://wiki.teltonika-networks.com/view/Mobile_Signal_Strength_Recommendations

RSSI for LTE is a calculated from several other signal related measurements: RSSI = wideband power = noise + serving cell power + interference power. For example, a 4G LTE modem might report an RSSI of -68 dBm, but:

RSRP = -102 dBm

RSRQ = -16 dB

SINR = -1.8 dB


In this case, the signal quality is actually very poor. This could be due to the device being some distance away from the LTE transmitter. It’s also possible that something is interfering with the signal, such as a building or other obstructions between the device and the tower.
RSRP is better to use for LTE than RSSI. RSRQ with SINR being the most useful as I understood it.
From https://www.digi.com/support/knowledge-base/understanding-lte-signal-strength-values, the RSRP and RSRQ is in the good range for signal, but then the SINR is in the cell edge, this to me indicates there is a lot of noise. And I have driven 1km and it doesn't change. I am not sure how you get 15-30Mbps, they are 1.45km from a tower and that still gives about 2-8Mbps, mostly under 2Mbps.

This is why I would like a spectrum analyzer to see where the noise is coming from. The tower that is more down than up is 1.55km away, but you can barely pick it up from their house, and all that is in the way is trees. It's mostly a flat plane there aren't any high buildings around either.

Even from the site you linked, the SINR puts them in the no signal range.
 

jbroo

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Messages
518
The utilization is 70% but the one tower 1.55km away is down more than up. But still on the B38 band the SINR is good, but then the tower is like 2.75km away
I connect to a tower 5.5km away, on B38. Direct line of sight.
 

jbroo

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Jun 12, 2020
Messages
518
RSRP is better to use for LTE than RSSI. RSRQ with SINR being the most useful as I understood it.
From https://www.digi.com/support/knowledge-base/understanding-lte-signal-strength-values, the RSRP and RSRQ is in the good range for signal, but then the SINR is in the cell edge, this to me indicates there is a lot of noise. And I have driven 1km and it doesn't change. I am not sure how you get 15-30Mbps, they are 1.45km from a tower and that still gives about 2-8Mbps, mostly under 2Mbps.
Yes I agree. All the RSSI will tell you, in comparison to RSRQ and RSRP is if your antenna is receiving a lot of other non-signal noise. So a high RSSI with low RSRQ/RSRP would suggest poor signal buried in a lot of wideband noise. Just suggesting a way for you to guess without an analyzer.

Even from the site you linked, the SINR puts them in the no signal range.

It's poor, but can be usable. I was getting 4-5mbps on a B3 tower with SINR of -10 to -20, before I switched to this B38 tower.

My feeling is cell utilization is the culprit here. Did Rain tell you the cell is at 70%?

My speed stats with an SINR of around 0, on a tower 5.5km away, when not slowed down by congestion:
1628063724325.png

1628064260715.png
 
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grok

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Phones have wifi analyzers now, won't some kind of app do the job?
 

jbroo

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Phones have wifi analyzers now, won't some kind of app do the job?
Wifi is not LTE signal, but you do have a point. Maybe there is an app to analyze LTE signal available... Most likely it will just tell you signal stats too.
 

GhostShow

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Yes I agree. All the RSSI will tell you, in comparison to RSRQ and RSRP is if your antenna is receiving a lot of other non-signal noise. So a high RSSI with low RSRQ/RSRP would suggest poor signal buried in a lot of wideband noise. Just suggesting a way for you to guess without an analyzer.



It's poor, but can be usable. I was getting 4-5mbps on a B3 tower with SINR of -10 to -20, before I switched to this B38 tower.

My feeling is cell utilization is the culprit here. Did Rain tell you the cell is at 70%?

My speed stats with an SINR of around 0, on a tower 5.5km away, when not slowed down by congestion:
View attachment 1119980

View attachment 1119992
Yeah rain did mention the 70%, but the thing is, even the connection isn't stable, I get notified each time the router loses connection and it's a lot. Not to mention the other tower that should provide better coverage is down more than up, 3 months and still alarms going off on it, and no resolution ..

BTW what router are you using?
 

Kiemo

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Yeah rain did mention the 70%, but the thing is, even the connection isn't stable, I get notified each time the router loses connection and it's a lot. Not to mention the other tower that should provide better coverage is down more than up, 3 months and still alarms going off on it, and no resolution ..

BTW what router are you using?
JB is using a B2338 outside router …
 

jbroo

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BTW what router are you using?
Yep, Huawei B2338 Outdoor CPE.

You might be right then, either there is interference, or the cells/towers have stability issues.

My stats right now. Note the uptime, with the last drop being a manual reboot on my side:

Uptime: 14day(s), 16:55:44
SINR:0 dB
RSRQ:-9 dB
RSRP:-103 dBm
RSSI:-74 dBm
Download:78.78 GB
Upload:8.30 GB
 
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GhostShow

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Yep, Huawei B2338 Outdoor CPE.

You might be right then, either there is interference, or the cells/towers have stability issues.

My stats right now. Note the uptime, with the last drop being a manual reboot on my side:
SNMP LTE Router Monitor
Last Refresh:Wednesday 04 Aug 13:32:45
Model:B2338-168
Connection Info
Frequency:2585000 kHz
eNB ID:302299
EARFCN:37900
PCI:446
Cell ID:36
APN Name:rain
Status:Registered
Uptime:14day(s), 16:55:44
Signal Info
SINR:0 dB
RSRQ:-9 dB
RSRP:-103 dBm
RSSI:-74 dBm
Current Speed
Download:10.37 Kbps
Upload:11.88 Kbps
Total Usage
Download:78.78 GB
Upload:8.30 GB
Look at those stats vs my friends.
The stats are better but the speeds are horrible. With lots of disconnects.
Tonight is the best I have seen
RSRP: -81dBm, RSRQ: -12 dBm
SINR flux between 2 and 8dB
Oh and as I was typing that it jumped to -2.
This seems odd
 

Kiemo

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Look at those stats vs my friends.
The stats are better but the speeds are horrible. With lots of disconnects.
Tonight is the best I have seen
RSRP: -81dBm, RSRQ: -12 dBm
SINR flux between 2 and 8dB
Oh and as I was typing that it jumped to -2.
This seems odd
Definitely interference …
 

GhostShow

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Messages
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Definitely interference …
Any suggestions on how to find out what is going on? Or will I have to fork out the money to get a spectrum analyzer or software defined radio to go hunt what is causing this?
 

Kiemo

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Messages
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Any suggestions on how to find out what is going on? Or will I have to fork out the money to get a spectrum analyzer or software defined radio to go hunt what is causing this?
No that’s way to much … get rain to give you a call and see if they can help you figure it out … nothing will help … you need to get the best tower with nothing interfering with your stats
 

jbroo

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Messages
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Look at those stats vs my friends.
The stats are better but the speeds are horrible. With lots of disconnects.
Tonight is the best I have seen
RSRP: -81dBm, RSRQ: -12 dBm
SINR flux between 2 and 8dB
Oh and as I was typing that it jumped to -2.
This seems odd
My RSRQ is marginally better. The question for me is still what is your RSSI? If its like -50 with those stats, you have a lot of noise. If it is -80 or lower then probably not too noisy.
 
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