I would like to introduce you to a new radio modem that we developed for very long range datalinks!
Some of the key features of the RFD900 are as follows:
- Multi point and point to point link capability.
- Long range >40km depending on antennas and GCS setup.
- 2 x RP-SMA RF connectors, diversity switched.
- 1 Watt (+30dBm) transmit power.
- Transmit low pass filter.
- > 20dB Low noise amplifier.
- RX SAW filter.
- Passive front end band pass filter.
- Open source firmware / tools, field upgradeable, easy to configure.
- Small (30 x 57 x 13 mm), light weight (14.5g).
- Compatible with 3DR / Hope-RF radio modules.
- License free use in Australia, Canada, USA, NZ.
These modems are designed to support long range applications, while being easy to use and affordable.
These modems have been flying in various platforms and have demonstrated excellent performance in real applications.
RFD900 modems are now available at: http://store.rfdesign.com.au
Support within APM planner and the radio configurator from Michael Oborne is already available.
It works seamlessly with APM planner, all radio Mavlink parameters are available.
Update, December 2014: The RFD900+ with improved specifications is available now at:
I never loaded an RFD900 driver.
In reality, the drivers are for the FTDI, not the radio. Many of the cloned FTDI cables apparently do not work. Are you using a legit FTDI cable with a 3.3 v interface? Do you have something else with a serial interface that you can connect to? Can you connect directly to the Pixhawk with that cable?
I have now tried connecting to the radios using a PC running Windows 7 (without success), so I don't think that the drivers from Windows 10 are to blame. Like the other PC, neither the Windows drivers nor the latest drivers from the FTDI site are letting me connect. I can see the COM port but can't read/write or upload any firmware to it.
The part that really puzzles me is that one of the radios blinks green just fine, but still won't connect to the PC.
Is it worth going through RFD's outdated drivers and hoping for luck?
You said it starts in bootloader mode? Make sure that you don't have any serial data being transmitted to the radio while it's powered on. This can confuse it. If you can't get it out of bootloader, I think I've managed to load the firmware onto it again to get it reset.
I've had problems getting some of the tools to work as well.
I've been able to use the Settings window.
I get the same error as you when attempting to use the Terminal window.
And I can't ever seem to get the RSSI window going.
But, as far as basic function goes, everything in the radio seems OK. The key was using another terminal program to communicate with the radio. I have "Terminal v1.9b" by Br@y++. I'm not sure it's the best, but I was able to connect with the ground RFD900+ and capture my failsafe settings with the correct AT command.
The radios seemed very picky about connection state. If you connected with Mission planner first, I couldn't get anything else (settings window or terminal program) working. If I got one of those going first, I couldn't get a Mavlink connection w/o power cycling.
I used a genuine ftdi driver and windows 10 for the above.
I'm now setting things up using a Raspberry PI for the telemetry stream. It connects reliably. And it's very persistent (I can power cycle the ground radio and the PI, let them reboot (~20 seconds), and the Mission Planner connection picks back up with no intervention on my part). Only thing that's bugging me at the moment is that the failsafe PPM setting has mysteriously vanished. So I'll be connecting terminal again before I fly.
I have two RFD900+ radios that I'm trying to connect to each other. The problem is, one of them is stuck in bootloader mode and neither of them will connect to my PC. I've tried using both the drivers that Windows wants to use as well as the drivers from rfdesign's site. In the RFtools I can see the right COM port that the radio is plugged into but when I try to connect to the radio it says that the radio 'Failed to enter command mode.' I'm running Windows 10 64 bit, build 17134.
Anyone have any suggestions? Thanks in advance.
I've been struggling with this question too.
One way that definitely works is to tether the FRSky X9D to the RFD900 using the trainer cord. In the trainer setup on OpenTX, you can specify the number of PPM channels and the length of the CPPM frame (presumably to match the channel count that you need). I set it up for 12 channels. 12 channels go in on the ground side and come out to the PixHawk on the other side.
That said, I'd like to avoid being stuck with a cord...at least part of the time. I could live with it at times, but really prefer wireless for takeoffs and landings. So, I'm back to the same problem.
The two basic options I'm looking at are
SBus to CPPM conversion sounds like a reasonable option, but it is one more point of failure.
Andrew Ferry said:
I am trying to create a RFD900x mesh. I have set the NetID to 100 for all 3 radios. I have verified all the radios can communicate with each other using a broadcast. I have issues where I cannot get the radios to relay. Does the LEDS light up on the relay node?
fw : RFD900x-AsyncRelease_V2.43.bin
NodeID : 1
DestID : 3 (Directed to Rover)
NodeID : 2
DestID : (what should this value be? 65535)
NodeID : 3
DestID : 1 (Directed to GCS)
Hi we have just aquired a pair of 900x modems. What is the best way to get 16ch of ppm into the modem? I have seen some connections to pins in a JR style Tx module bay but that is a bit of an ugly solution. I like the idea of connecting a conventional 2.4ghz receiver to the ground modem but most cppm receivers are limited to around 8 ch. May be a 16ch sbus receiver with a sbus to cppm converter in the link to the modem? Would love to here what others have done with this setup. Of coarse it would be great if the RFD guys implemented sbus input. Seems like everyone wants it...
The 900x supports up to 16 channels of PPM passthrough.
Fully support MAVLink up and down at 19200 at 1W each way
same module set one as RX and the other as TX