simpleRTK2B - Starter Kit LR

Anyone who has used this starter kit, could you tell me about your experience with it? Where do you have the radio antennas mounted? Do buildings and walls change the effective distance? Is this a preferable option compared to running an ntrip base station as the cost is pretty similar.

I used this kit at the beginning, the antenna of the base (radio) was installed on my chimney (8 meters high totally clear).
My problem is that the radio waves are stopped by the smallest small forest. So I went to Ntrip correction.
So if you have a field clear of any obstacle, no problem up to 4 kilometers around the antenna.
Otherwise and if your mobile phone is receiving everywhere, go directly to an NTRIP solution.
Only my experience.

I think I’m going to attempt to use the WiFi master as it seems like a very simple solution for ntrip
My issue with a base station is finding the ideal place to have it, internet, power, visible view of the sky.
Wish I could have gotten away with using a local rtk2go station but nothing within a 30km radius.


Im using ntrip from a base station 40km away and am happy with it. Occasionally when i first enter a field I may have to shift the ab line 100mm

I have set up a base station with the XLR radio’s and seems to be a real improvements.
with the LR radio it really doesnt take much to block the signal, but the XLR signal had no problem going to farms and trees lots. more testing is needed but if from what I seen if you can get to a high point in the area with no hills blocking then the signal should be stonge enough.

Take a look on the forum where @torriem and myself discuss using the same radios as the XLR but without the arduSimple carrier board. At that time you could buy them much cheaper, but they need an interface board or something plus coax adapter and antenna.


Also, normally you only need one XLR radio for the base because your rovers only receive so the XL is good enough for them (and compatible)

I verified with Ardusimple that their XLR radios are Digi SX with 9Xtend hopping firmware. Ardusimple has made a nice adapter board for the surface-mount Digi module to adapt it to the old Xbee socket which is nice. But you can certainly solder your own wires to a bare Digi module and connect that to the relevant pins on the Ardusimple board. For XLR, the base station uses SX Pro modules (1 watt), and the receivers are just SX modules. If you want to work with the Digi modules yourself, you will need a USB programmer to load the firmware you need and set some parameters (to prevent conflicting with other 900 MHz radios that might be in your area).

If you want to use your own Digi modules to receive signal from an Ardusimple XLR base radio, you’d need to contact Ardusimple to find out what hopping prefix they are using and id.

Could the prefix and id be pulled from their unit via the Digi software & USB programmer?

1 Like

Yes indeed. You won’t be able to directly use the Ardusimple module with the USB programmer because the module is soldered to the board and won’t fit the socket. but you can use any USB to 3.3v serial adapter. You can read all parameters with XTCU.

There’s a “hopping preamble id” which indicates which channel the hopping pattern starts on, and then there’s “Network ID” which is a kind of digital squelch to discard packets that don’t belong to your setup. I recommend changing these values from the ones Ardusimple ships anyway. Just in case your neighbor happens to be using Ardusimple radios too. Or some other system that uses Digi radios.

1 Like

Unfortunately XLR is not allowed in the UK as far as I’m aware

1 Like

There’s a pretty obvious hack to fit a Digi XBee Extra Long Range Radio to an Ardusimple simpleRTK2B V1. It requires a small piece of 2mm pitch Prototype PCB, 2 x male 2mm pitch headers, 2 x female 2mm pitch headers, 1 uF and 100 pF capacitor, jumper wire to 3V3 power source.

Assume pin 1 is at the top of the XBee Headers. Put an over-size piece of 2mm pitch Prototype PCB over the XBee headers held in place with male header strips under the board. To the left of the headers run female headers on the top connecting pins 2-Tx, 3-Rx,10-Gnd,11,20.

Pin 1-3V3 needs to be powered with a jumper wire off the main board from 3.3V. To help reduce noise, Digi recommend placing both a 1 uF and 100 pF capacitor as near to VCC as possible.

ArduSimple LR and XLR Radio Kits are about double the component cost from other suppliers (eg XB9X-DMUS-001 and XBP9X-DMUS-001 respectively for US castellated module with U.FL antenna connector, antenna and IPX U.FL IPEX cable).

ArduSimple fit the modules to an adapter like GitHub - faludi/xbee-smt-tht-adapter: XBee SMT -> THT Adapter, including XBee PRO SX. Digi has good PCB design and manufacturing instructions which should be carefully read including attention required for layout (eg grounding, heat dissipation and RF performance) and solder reflow requirements if they are to be sourced from other suppliers.

Very good observation! I guess there was a method to the Digi madness when they switched to this silly SMD form factor.

The pins line up perfectly with the XBee headers, you can see them poking through in the ArduSimple radio boards:

But you’'d be wrong not to sit the module on a board.

I have wires soldered to the pads and it works fine. It will also work fine with the pin header as @m_elias says. Ground, 3.3v, TX, RX, Reset will all connect as they should. The Digi instructions don’t really apply here. We’re not using reflow ovens and surface mount soldering. RF performance is about antenna placement which again doesn’t apply here, since a pigtail attaches to an external antenna. Plus if we fry a unit it’s no big loss. Not really sure what you’re going on about.

The other side of the xbee socket has only one connection on the SimpleRTK and that’s another ground. However on the SX module it lines up with the ioref pin, which is itself not connected on the SX module (it’s unused). So probably would be fine here. If not, leave that pin out when doing the other side which really is just about mechanically holding the module the socket.

Personally I would leave off the TX pin also. You really don’t want your rover talking on the airwaves if you forgot to turn off the outbound traffic on UART2.

Specifically, heat kills electronics and the higher the transmission power the more heat produced. It gets bloody hot in Australia which leads to interesting things often fixed with a fan. The specs use the board the module is sitting on to dissipate heat (ie it’s not accessible) - Recommended footprint and keepout.

The recommended footprint includes an additional ground pad that you must solder to the corresponding pad on the device. This ground pad transfers heat generated during transmit mode away from the device’s power amplifier. The pad must connect through vias to a ground plane on the host PCB. Connecting to planes on multiple layers will further improve the heat transfer performance and we recommend doing this for applications that will be in transmit mode for sustained periods. We recommend using nine 0.030 cm diameter vias in the pad as shown. Plug vias with epoxy or solder mask them on the opposite side to prevent solder paste from leaking through the holes during reflow. Do not mask over the ground pad.

Of course it will work if the right connections are made but that doesn’t mean the module isn’t being used as a slow burn fuse. It will depend on the actual environment where it is used, so a base station sitting on a pole will be different from a module in an air-conditioned cab.

Maybe there are more practical ways of handling heat dissipation (eg using a properly fitted heat sink and thermal paste, wire, adapter board with thermal past etc).

Oh sure. But except for a tiny bit of heat dissipation through the ground plane the Ardusimple radio modules aren’t going to be any cooler. The point is you can get the equivalent to the Ardusimple modules with just a header soldered on. There’s precious little by way of heat dissipation you can do to these modules short of putting active cooling on the can.

The ardusimple modules do have a nice SMA (or maybe it’s RP-SMA) connector on there board which is more robust than a pigtail.

And it’s not just the radios that you have to worry about overheating. There’s the GPS receiver itself. I recommend putting the whole works indoors and just have the antennas outside. That’s what I do. I’ve used a 1 watt transmitter pushing through a 50’ coax cable up to an antenna for years without issues, loss-wise.

On my new set up that I’m going to work on this summer, I’ll have the GPS antenna on the roof of my shop with a 30 foot cable on that, and then the 900 Mhz digi transmitter will be on a 50 foot cable up to the top of a mast, with the radio module and the GPS receiver all inside mounted to the wall.

If I understand correctly, putting my simpleRTK2B in a watertight 8x8 electrical box sitting 5 feet on a mast above my house is going to heat up to much? I’m in central Saskatchewan and we do get warm in the summer, but not like down south. I have a usb adapter inside as well, which would create it’s own heat. Any suggestions?