I have been using the RBLHGR&R11E-LTE6 for over a year now and it has been great. On setting up the dish on 3UK I had plenty of choice of cells and was able to achieve both Excellent Signal Strength and Quality. As a result I have always had a steady 35mbps download and 9mbps upload.
Two weeks ago I noticed my internet was unusable and a reboot did nothing. Logging in to my app I could see that the signal had dropped to Good signal and Quality and would sometimes switch cells. I came to the assumption that the dish had moved so go the ladders out. I had marked the pole and dish during installation and found they were in the exact same place.
I attempted to adjust the dish to improve the signal but cannot get an RSRP better than -86db despite consistently having an RSRP of around -50db before. This is true of all cells I check.
What could be the cause of the sudden drop in signal? Is it likely to be a hardware issue of software issue?
Check your antenna cable paths and reseat the connections to eliminate that as a possibility. I hope it’s not hardware.
(Although, the default for LHG R kits has them connected securely with a drop of clear glue on each port, is it possible that weather has rattled it?)
What’s your ROS version and LTE6 card’s firmware version? In some cases, towers adjust their coverage majorly so this may be par for the course.
I’ve used the 3 network for 4G failover at customer sites so I’m familiar with them sometimes changing things up.
One of the most common gripes I have is their towers preference of B20 over B3 so in most cases I force B3 to get 15MHz instead of
B20(5MHz)+B3(15MHz) CA2 and slow response times until traffic ramps up.
RSRP of -86db does not indicate on any way loss of connection…
You should take into account the RSRQ SINR and RSSI values too…
Also you don’t mention what the ROS version is and what the modem firmware version is… ???
RSSI value is completely useless … the same way as voltage measured over wire pairs on UTP when assessing ethernet throughput. RSRP at least gives information about level of usable signal while RSSI includes also noise, interference and channel load (traffic for other clients of same cell). However considerable drop in this value would indicate something’s wrong with attached antennae and/or Rx part of LTE modem.
You’re right about importance of RSRQ and SINR though, the later actually defines possible higher layers throughput and the former being quantity which is relatively simple to measure … it’s being used indirectly between eNodeB and terminal to adjust radio link parameters. Since SINR can’t be directly measured, it’s calculated from other quantities. Formula is not exactly trivial, so many terminals (LTE modems) don’t bother displaying it.
@mkx how can it be useless since it is used in the calculation of the RSRQ value ?
I think all the values ( RSRP, RSRQ, SINR and RSSI ) have their importance…
Is there any value you take into account the most ?
RSSI is useless if used stand-alone. If it’s used in context of the rest of numbers, then it’s not relevant. As you wrote, its only relevance is in calculation of more meaningful numbers.
If you’re looking at those 4 numbers, look at RSRP and RSRQ … both are meaningful already when modem is idle and are usable to optimize radio interface, e.g. when turning antennae. When RSRP is good (e.g. above -80dBm), RSRQ will give good assessment of maximum possible throughput (as a part of maximum cell throughput) … RSRQ better than around -3dB is excellent, RSRQ belliw -8dB is mediocre and anything below -12dB is bad. If RSCP is below -80dBm but higher than -110dBm (my own estimate of “loss of signal”), RSRQ needs to be a bit higher than numbers mentioned previously to get similar service. In theory SINR is the ultimate quantity defining possible throughput. The problem is that SINR calculation is complex and not standardized so every vendor does it slightly differently. Which means it’s fine if one compares value shown by same device model, but can’t be compared between different vendors.
As a side note, there is another part of the infrastructure that could be accountable for your problems.
Check if the provider tower is out of order or simply if it still does exists.
I had the same situation, where the provider simply decided to decommission the band/antenna for my area.
This might be of help: https://www.cellmapper.net/
While cellmapper is a great resource, it won’t be possible to reliably check without becoming a data source yourself and walking nearby the tower to gather data. It’s crowdsourced. You’re at the mercy of anyone passing through with a device in collection mode that is also actively uploading to the project. If all else fails, you can always pop the SIM in a phone, take a walk down to the tower and use Network Cell Info Lite (the free version) on Android to see what bands are available, though unless you know how to manipulate your device’s bands, you’re at the mercy of the OEM/tower preferences and unlikely to be able to force yourself onto a band like you can with the granular control afforded in ROS.
Yeah they got the largest chunk of the 5G spectrum so it’s nice to see them moving quickly to roll it out.
They’re making themselves a very cost-viable option for most price discerning consumers.
I hope their board doesn’t think this is the time to increase costs exponentially.
£21 per month (fixed term contract usually with 3 or 6 months reduced price for 12/24 months) is hard to beat but the MVNO’s offer unlimited for £20 a month with no contract. Although, if you have poor coverage with Three, you can always use the Asda Mobile which is an MVNO of the Vodafone network but unlimited data with no speed cap is £30.
Ok so to answer a few questions from above:
ROS is 6.42.1
All antenna connections are in place.
The cell I usually use is active. I can connect to it. The signal is much lower. I confirmed band 3 still works by going to the site and using my phone.
RSRQ is consistently around -14 no matter which cell I connect to.
I have the router set to only connect to band 3.
I live on a hill and can see multiple masts from my location. When I set up the dish I could choose from multiple cells in all directions and I got excellent signal quality and signal strength. I tested them and opted for the one with the best and most consistent speed. Now I cannot get an RSRP better than -85ish and an RSRQ better than -14ish.
I have tested a different power connector, different SIM, different cables. Nothing changes.
I’m becoming more and more convinced that the issue is hardware related and I’m unfortunately out of warranty.
Any suggestions on what I could try myself? Anywhere in the UK I can buy spare parts or send for repair? Would replacing the modem be a good place to start?