LtAP LR9 LTE gateway (DIY instructions) - AU/US915

DIY instructions for an LtAP LR9 Gateway (LTE + GPS, not that the GPS seemingly matters)


I have one of the Mikrotik wAP LR9 gateways (exterior rated) running on AU915, and it works well (although I could hope for a move to BasicStation instead of the UDP forwarder).

There is now an LtAP LR8 package for sale, which uses the LTE and GPS enabled LtAP platform which is a nice step up in capability and outdoor robustness.

There is currently no LtAP LR9 variant. I’ve not asked why, but I had a recent need for an LTE capable gateway and the price difference between an internal-rated one (like the Dragino LG308) and building one on the Mikrotik platform was zero. So I went for it.

Ordering and Building

I ordered a

Mikrotik 2.4GHz Access Point with 4G (LTE) LtAP LTE kit (RBLtAP-2HnD&R11e-LTE)

and a

Mikrotik R11e-lora9

and these arrived as individual units. We popped the (robust!) case open and fitted the board, fitted a U.fl to SMA cable (not included!) and popped out the cutout to mount this SMA connector to the internal bulkhead (it’s even got a hex indent to fit…nice engineering).

We’re using a foldable stubby antenna on this for the LoRaWAN side, and it fits nicely inside the pop off connector cover. The unit has internal LTE and GPS antennas (GPS is also broken out to a connector, and I believe the LTE can be as well). The main purpose of our unit is a portabile GW, not a mountainside install (yet) so a self contained unit with no bristling antennas is nice.

Network setup

This was harder, and the driver for this forum post for future reference.

The wAP (prebuilt) unit would come up with a DHCP server on the wifi (acting as an AP), so you could connect to this with the phone app and do the setup.

The LtAP, at least with the firmware it came with, did not do this. It reportedly should have, but it did not. The Wifi AP was there, but the DHCP server didn’t work, and the unit came up with an address of which of course wasn’t connectable.

None of my accessible devices have Ethernet, so I persisted with wifi. Mikrotik have a “Winbox” app which purportedly would connect to a MAC address. It’s name correctly implies it’s a Windows app, luckily I found someone had cross-packaged it for Mac using one of the virtualisation apps. That worked, despite me wondering what I was downloading and using.

Setting up from there was mostly the same as the wAP – not simple or pleasant, but logical:

  • Remove the wifi interface from the Bridge
  • Add a DHCP client to the Wifi interface
  • Add an Authentication to the wifi interface (as I wanted it to join my network when it’s at home)
  • (and do this last) Change the wifi interface from AP to station, type in the SSID and click Advanced (if required) and chose the authentication profile you created above.
    [This then becomes active immediately you press the ok button, hence the important of getting the DHCP client set up first]

If you screw this up, power off and power on holding the reset button for ~5s (until the light flashes). It’ll erase all your progress and you can start again.

LoRaWAN setup
The Lora menu option will not be present. The board will not be seen. This may induce thoughts that the LR9 is broken but this is unlikely.

  • Upgrading the firmware is a good first step.
  • Then get a terminal (ssh to it, or use the web terminal although frustratingly that doesn’t support pasting). Type /system routerboard usb set type=mini-PCIe
  • Go the Mikrotik website. Download the modules for MMIPS for the firmware version you just upgraded to (I’m brave, used Testing). Unzip this, then scp the Lora module to the base directory of the router. Reboot using /system reboot and the module should auto install (must be a the matching version)
  • When it comes back up, you should have a Lora menu. You may need to add your TTN server (the TTI v3 servers are there, but not the TTN/TTS variants)
  • I recommend putting a regular reboot in the crontab. Maintenance on the TTN side has thrown the UDP forwarder off before for days/weeks, and a reboot fixes it and doesn’t take more than a few seconds. I use /system scheduler add interval=1d name="Reboot Router Daily" on-event="/system reboot" policy=\ ftp,reboot,read,write,policy,test,password,sniff,sensitive,romon \ start-date=jan/01/1970 start-time=02:02:27 but you may want to tweak the time.
  • You can turn on the GPS. I’m not at all convinced it’s useful for anything on TTN (please educate me) but hey it’s free.

Setup on the TTNv3 side is as you’d expect, just use the Gateway EUI and setup for unauthenticated access, with the bandplan etc that you’d like. It should all just work from this point.

Let me know if you have any questions, although I’m not an expert in Mikrotik (this should be evident). It’s a nice unit, just wish setup was a trifle easier. I’m yet to find a physical SIM to get the LTE working, will report back if there is anything special there.

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