A solution for poor LTE signal strength?

Mikrotik SXT LTE is an outdoor LTE modem and router, that may provide a far better signal and data rates for fixed installations than an indoor solution.

The best solution for a network uplink connection is fibre, but it is not always an option. Cellular data may deliver more bandwidth than ADSL connections which utilise old phone copper wires. WiFi-router-firewall-LTE combo boxes are gaining popularity for a reason. It is a unit that looks like a WiFi access point but contains a SIM card slot for uplink connection. In Finland these are common even in fixed locations like homes, small offices and rural locations because unlimited cellular data plans have been inexpensive. Too bad that many have been disappointed by the actual data rates they are getting. Concrete or brick buildings, especially with modern thermal glasses, are very good at keeping cellular signal from getting inside the building. In rural area the distance to the cell tower is often too long for good data rates. What can you do?

The most common solution is an external antenna. The problem with that solution is attenuation in the cable. As a rule of thumb the loss is 3dB per meter and an additional 3dB per connection. For a 5 meter (17 feet) antenna cable that totals for 5*3dB+2*3dB or 21dB loss. Since the internal antennas are typically 2dBi you would need to install a 23dBi external antenna just to get equal signal level. Of course you can install a 30dBi antenna for a 7dB net gain, but such high gain antennas have very narrow beams. Narrow beam requires precise alignment. If the antenna is just slightly off or moves with the wind,  you may end up with much worse signal than the internal antenna already provided.

MikroTik SXT LTE

MikroTik SXT LTE (~200€) is an outdoor antenna-LTE modem-router combo. The antenna is in the same box, so the antenna cable is just an inch long. The gain of the antenna is 9dBi (eightfold signal) but is not too difficult to align. The device is connected to the internal network by ethernet cable, that can be 100 meters long without any decrease in data rates. You could place the device on a nearby hilltop, if that’s what is obstructing your connection. The ethernet cable also supplies power, so you don’t need to worry about providing power. Just keep in mind that you need to use weatherproof ethernet cabling and protect it from surges. If the cable is longer than a stub, you need to put surge protectors at both ends.

MikroTik SXT LTE
MikroTik SXT LTE & Ubiquiti surge protector

SXT LTE can receive at 100Mbps and transmit at 50Mbps. The ethernet port is 100Mbps. There are LTE data plans with higher nominal rates, but SXT LTE cannot take advantage of them. The device comes with a 24V power supply and an ethernet adapter. For longer cable runs you should consider upgrading the voltage to 48V to minimize losses. The maximum rate is 57V.


Under a small protective door there is an ethernet port and a place for a legacy SIM card. The door is made of hard plastic, but seems to be fairly weatherproof when closed properly. There is no seal, so putting some sealing tape over the door seams and the ethernet opening should be considered. SXT LTE comes with hardware for mast attachment, but no surge protectors.

MikroTik routers use IP address by default. You can connect to it using a browser or MikroTik’s WinBox application. The default username is admin and password is empty. The only required setting is the PIN code for the SIM card, if it has one. The default is empty. In the browser user interface the path is: top right WebFig > top left Interfaces > select lte1 > enter PIN.

MikroTik WebFig
MikroTik WebFig

The outdoor device doesn’t contain an ethernet switch or a WiFi access point, so you need to provide those in the internal network. Usually they also provide a DHCP server that you need to switch off. A DHCP server provides IP addresses for clients, usually from subnets or If the clients get one of those addresses, they won’t be able to connect to the SXT LTE, because it is in a different subnet. The SXT LTE also runs a DHCP server by default providing addresses from subnet, but it has a two second delay. If there is some other DHCP server in the network, it will serve the clients first. That’s why you need to turn off all other DHCP servers. Typically this is the only configuration change required for the internal network.


LXT LTE only supports LTE bands 3 ja 7 (1800MHz and 2600MHz), there is no support for GPRS or EDGE. The fourth generation LTE network is not ubiquitous, so outside of it you need to find another solution.

The cell operators don’t volunteer their tower locations or info on the frequencies in use. This makes them free to change them without notice, since the customers aren’t promised anything. Unfortunately without tower location antenna alignment becomes a manual process. SXT LTE has five LEDs to show the signal strength, so you can align it at least approximately. Fortunately the 9dBi antenni is not too directional.

Different cell operators may have very different signal strength in any given location. You should have a handful of SIM cards to try when installing. The best signal for another operator may come from a different direction, so you should re-align the antenna for each SIM card.


29 thoughts on “A solution for poor LTE signal strength?”

  1. Hi!
    I’ve been searching some info. guidance for this antenna with little luck.
    I’m from Spain, but I think that you could help anyways.
    I live in aparted home with no access to ADSL or fiber at all, so my only options to have internet access are WiMAX, Satellite and 4G/LTE networks.
    Nowadays I have WiMAX but it’s terrible, so since I have pretty good signal of 4G/LTE in my phone, and when that happens I can surf the web and play videogames pretty well, I came with the idea to buy an LTE antenna like this.
    If I buy this antenna and I have the APN settings of an operator, can I connect to it for free?
    I ask this questions, because as I can see the microSIM slots are for “backup”, but if you cannot connect for free, then I don’t know how the operator how can charge you your data usage of their network.
    If I don’t want to setup the APN settings, can I connect a SIM card and it will be Plug&Play or almost Plug&Play?
    Maybe I did stupid questions, but I don’t want to spend ~100€ for nothing.

    1. You will always need a SIM card with a data plan to connect to an operator’s network. In the new SXT LTE Kit there are two SIM card slots where the second one can be used for backup. You could use another operator’s SIM if the first one goes down.

      No, you won’t be able to connect for “free”. You need to pay to the operator to use their network. Perhaps you can get a secondary SIM card to the one in your phone? At least here in Finland that would save you some money. The secondary card will have the same phone number but of course the SXT LTE won’t ever answer your calls.

      Typically the SIM card contains all the necessary settings so you won’t have to configure anything except for the PIN code (if your SIM has it). It is virtually Plug’n’Play.

      The new SXT LTE Kit will replace the old SXT LTE. The new model has two SIM slots, two Ethernet ports and supports all possible cellular data connections. The old one only did LTE on bands 3 and 7, which are typically used in urban environment. Just make certain you get the new one and you’ll be fine.

      1. Wow! That was a fast response!
        Thank you!
        So it’s a must to have a SIM card, ok.
        I wasn’t sure that this let it you have free connection, but I asked anyways to clarify it.
        Ok, so if I buy this, and have a new number (it would be only for the SXT) I would remove the PIN using it first from my phone, so in the SXT it would be fully Plug&Play for the SIM part.
        But I have new questions.
        This device has some management utilities like QoS for example?
        Since it is made by Mikrotik and they have the RouterOS, I suspect that it will have typical routing and network management, but I want to be sure.
        If not my idea was to connect this antenna to a PC with two network interfaces and use that PC like a router, one interface connected to the SXT and the other to a switch, and then make QoS, NAT and this kind of things on that PC.
        And since the new SXT (is the only that I can find in Spain) has 2 SIMs, is the second only for backup? Or it can be used to do load balancing?
        It would be very interesting, so I could have two different data plans, one for web surfing and other typical services like FTP, IMAP and STMP, etc. and the other one for gaming.
        Thanks very very much again.

        1. Yes, SXT LTE has full RouterOS. However, you cannot access QoS on the LTE side, it is the operator’s network. You could create your own queues on the local network before the LTE to shape traffic.

          No, you don’t need any other router. SXT LTE has a firewall and can do NAT by itself.

          No, SXT LTE has only one LTE radio so it can connect to only one LTE network at a time. The other SIM is for failover only. You can’t use it while the other is in use.

  2. Hello,
    Is it possible to have the Mikrotik SXT LTE kit {RBSXTR&R11e-LTE} behave just like a modem ie
    WAN-Mikrotik SXT LTE kit-another router issuing LAN ip addresses by “turn off all other DHCP servers” as you say above, or something additional ?
    Thanks in advance,

    1. If you have the new model with dual Ethernet-ports and dual SIM slots you can set up SXT LTE Kit as a L2 bridge. It is known as passthrough mode in MikroTik parlance. You have to do it with command line, there is no GUI for it. See Passthrough Example

      If you only want to turn off the DHCP server you can do that in either model. In that case SXT LTE will still function as a NAT and route traffic.

  3. Hi Petri,
    Many thanks for writing such a detailed review of SXT-LTE, i dont think there is anyone other than you who has done it.
    I have also got the SXT-LTE (new model), yet to install it. However would like to understand is it fairly simple to connect a ethernet router to extend the internet over WIFI? Appreciate if you provide your guidance on it.
    Many thanks.

    1. Yes. However, you don’t need a router since the SXT-LTE will do routing, NAT and firewalling. You could just use bridged Wi-Fi access points. If you just connect a router’s uplink/Wan port to the SXT-LTE it will work. There will be double NATting, but for ordinary use it won’t do any harm.

  4. Hi
    Would the MikroTik SXT LTE do the same job as an Archer Wireless Dual Band 4G LTE Router that I currently have.

    1. Quite close. SXT LTE doesn’t have an Wi-Fi access point built in. The benefit would be that SXT LTE has a directional antenna and is weatherproof. You should place SXT LTE outside, as high as possible and direct it to the nearest cell tower. You’d get a lot better signal than with an indoor omnidirectional device like Archer.

  5. Hi
    I was surprised how easy it was to get configured, just put in the APN, update it and it connected to EE in the UK. The signal strength LEDS do nothing, how do I get them running? Is there anything else that I should configure?
    Best regards


    1. I presume you have the new model with two SIM slots? The first firmware versions didn’t support the LEDs. Upgrading RouterOS should do the trick.

    2. Hi

      I can’t get the SXT LTE to work on an EE sim even after setting up the APN yet I have another SXT LTE from another company that came pre-configured which is password protected and it works straight away any help would be greatly appreciated I assume there is another setting I need to change to get it to work outside the LTE settings?

      Many Thanks

      1. Your best source for help would be MikroTik Forums either General of Wireless Networking. You should try to figure out whether the problem is connecting to the LTE network or some local issue. Do you get an IP address from the LTE network? Have you tried some other SIM card? These would be good clues to include in your post. By providing more information you increase your odds to get useful help.

  6. In theory great device, in practice – keeps disconnecting every couple of minutes in our case. The only way back is to reboot the device. We made it reboot automatically every time the connection is gone for over 45 seconds, so as the device goes down every few minutes, it makes it quite useless. Apparently there is a bug in the modem driver, which has not been fixed for the last two years.

    If you have any ideas about how to make the device more stable, I would really appreciate it.

    1. I wrote about the original SXT-LTE and I have deployed like a dozen of them and they all work fine AFAIK. I have deployed a couple of the later SXT-LTE Kit (with dual Ethernet ports) and I haven’t heard any complaints. I believe they run some old RouterOS, I don’t think their owners have upgraded them since I left.

      Could it be that you have a faulty unit? I haven’t followed the topic on MikroTik forum. Is this a known problem. They way you write makes me think so. In that case I can’t help. If this is the case then I’m just sorry, because the product is good. Too bad if the implementation sucks.

  7. Hello, i have two issues.
    I’ve tried to configure two different APNs, both associated with the LTE interface but the LTE interface does not become UP. Do you know if the R11e-LTE supports many different APN’s ?
    I want to simulate a failover between SIMA and B. I configured default APN and i put the SIM in slot B and from System Routerboard i have selected SIM A. I’ve applied the script presented here https://wiki.mikrotik.com/wiki/Dual_SIM_Application in order to force the modem to move traffic from SIM A to B. It doesn’t work.
    Does anyone know how it is working failover between SIM;s?

    1. Have you tried MikroTik Forums? There you’d get far larger audience and more combined experience. I have set these up as a failover for a cable connection, so I haven’t needed multiple SIMs. In some occasions you’d need to realign the device if the other cell operator is using some other tower.

  8. Hi there,

    Thanks for the info to date. My house, in a rural location in Ireland is approximately 3.5km from the nearest tower and we receive around 1MB download speed. Would the Mikrotik SXT LTE work in this situation?

    1. If you can receive 1Mbps indoors with cell phones or such, I would assume using a directional antenna higher up and placed outside would improve the reception. If the telco is the limiting factor (intentionally or unintentionally) then it won’t help. OTOH, SXT LTE is inexpensive enough to just try out. Just remember to place an Ethernet surge protector before you bring the cable indoors and ground the protector properly. (At least Ubiquiti sells an inexpensive protector but any brand will do.) Use outdoor cabling, too. Ordinary cables don’t like UV or outdoor temperatures.

  9. Hello Petri,

    Your explanation is lucid and has cleared a lot of doubts.Which would be a better choice between the SXT LTE Kit and the SXT LTE 6 kit .I am located in a rural area in India and was using Wimax with the CPE mounted on a pole.The ethernet cable length is around 15 -20 metres between the antenna and my workspace.Will there be any loss of signal .Besides we are located at a height on a hill so it is prone to thunder.Would I need a surge protector at both the ends…Thank You For Your Support.

    1. A 20 meter Ethernet run is not a problem, it will run up to 100 meters (but can’t feed PoE power that far). If your local carrier supports the new features that come with SXT LTE 6 Kit then go for it. I haven’t had a change to install one yet.

      Yes, do install a surge protector at the point where you run the cable inside and ground it well. It is useless unless well grounded. I have used Ubiquiti’s surge protectors as they are reasonably priced around here, YMMV.

      1. Thank you for the prompt revert Petri.I”ll go with your advice.

        Just a single question .How well does the Mikrotik LDF LTE 6 Kit or the LHG LTE 6 Kit compare to this.Except Higher Gain due to a dish antenna are there any other specific advantages with respect to speed and operability

        1. LHG includes a bigger antenna with higher gain. It can connect to a further AP, but won’t necessarily improve your speed. The speed depends on your carrier. Higher gain antennas are trickier to aim.
          LDF on the other hand doesn’t include an antenna at all. You should install it in some other dish antenna, like an old satellite TV antenna. Then you will get even more gain.

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