Cell Lock MikroTik LHG R11e-LTE

Cornwall internet isn’t great where the in-laws reside. When they moved in it was ADSL and topped out at 2Mb download and 0.2Mb upload. Then some big news hit, Cornwall was to get a massive grant from the EU to create a fibre to cabinet or premises network throughout Cornwall. Once this had arrived we signed up and got a blistering 10Mb download and and even more exciting 0.4Mb upload.

Time to look for a new solution.

A dual sim EE setup running in to a proroute 4G router was the next installation. A quick survey around the garden showed we would get about 20Mb download and upload. We popped an omni directional antenna on the garage and fed that in to the router. the reason for 2 SIM cards was that was the cheapest way to get the most allowance. we got 64GB on each card per month and they would switch over when the allowance ran out. Once or twice we did go over but it was at the end of a month with only a couple of days to go.

Recently that setup has changed to a single sim running 300GB a month. This has been great but the performance of the connection has gotten a lot worse. The router isn’t great at giving information about the type of connection and doesn’t have tools to lock to a cell frequency which would have probably helped.

LHG the rescue

When I saw these all in one router directional antennas I got very excited. A proper router with a good chip and a fast 4G modem. We didn’t go for the CAT6 version as I was sure we would have seen the benefit but there is the option of switching out the PCIe card later on if we need. The only downside is that it is 100Mb ethernet port which if you do get a carrier aggregation link over that you wouldn’t be able to fully use it.

I got one ordered to the property and headed down the next weekend. I built a wooden pole tripod to mount it to and proceeded to march around the garden and edge of the house to find a suitable location. It is POE so I had a super long ethernet cable which made this process much easier.

Eventually I found a good location, I was seeing about 30-40Mb Down and Up! But sometimes it would drop to 15Mb and wouldn’t go higher. I didn’t know why.

Luckily I have a old colleague who works for EE in there security team and he cut his teeth on the temporary mobile site installations. HE explained about the best band to be on for bandwidth (3) rather than range (20) inside each band there are also different frequencies. The lower the frequency the lower the bandwidth.

The MikroTik LHG shows you all the detail and I was seeing that it would sometimes connect on the 10Mhz frequency inside band 3. This is not ideal as there is also a 20Mhz it could be connecting to.

A quick google and this article pops up.

AT*Cell=<mode>,<NetworkMode>,<band>,<EARFCN>,<PCI>

where

<mode> :
0 – Cell/Frequency disabled
1 – Frequency lock enabled
2 – Cell lock enabled

<NetworkMode>
0 – GSM
1 – UMTS_TD
2 – UMTS_WB
3 – LTE

<band>
Not in use, leave this blank

<EARFCN>
earfcn from lte info

<PCI>
phy-cellid from lte info

So a line like the one below would lock to the phy-cellid and EARFCN entered.

/interface lte at-chat lte1 input="AT*Cell=2,3,,1300,384"

Only problem is that the router R11e-LTE forgets about this every time it boots. To overcome this you can schedule scripts to run when you require. In this case startup and then every hour just to make sure it keeps to the same cell frequency. Pop the same line of code in to the “On event” section of a new schedule and chose startup and an interval of your choosing and you are good.

Currently I am seeing up to 60Mb download and a steady 25Mb upload. Which is great. But what next? Well I’ve got my eye on Starlink which has just gone live in this part of the UK in January 2020.

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