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 am currently using RFD900+ (and RFD800+) with RFD Multipoint SiK on plenty of modules and I have two questions:
A) The datasheet specifies that NETID max val = 499. However if we want to maintain a fleet with more than 500 pairs and would like to have unique IDs I would like to set values greater than 500. At first sight, this seems to work. Is there any risk associated with? Or does somebody know where the limit comes from? I already checked with the manufacturer concluding that if there is a limit, it's due to the firmware.
B) On some of my modules I cannot set TXPOWER to 27 (500mW), but it always sets it to 26 instead if I check afterwards. It even seems that all odd numbers are "blocked" and are always floored to the next even number. Does somebody know about this behavior? Or know how to mitigate or get rid of it?
Thank you in advance for any reply.
Paul Clark said:
Do you calibrate the rssi for mission planner? I see 100% or 99% all the time just before it loose connection
Looks like Lanzo may be using the RFD900+ as that has the V1.xx firmware available. only a guess here mind you!
Can you elaborate here RFD433? or am I missing something!
Roger Ronald said:
433 would be the best choice.
I'm running 2.61. Since you're running a way different number, I suspect you have something other than the RFD900x.
Most of the RFD FW updates are to add features. Unless you need a new feature in the new version, I wouldn't bother.
Dear Ronald I have set at 20 dBm the 2 radios and now the extension cable works, I have a cheap USB meter and if it's precise it is measuring 5.14 V 0.12 A 0.643 W.
The drone radio is powered by a Turnigy 5V BEC and it was at 24 dBm because more power was causing jitter to the servos, now it's 20 dBm, I think it will be ok because I use a Yagi on the ground and a quarter dipole on the plane, it was working well upto 20km with a cheap Rock telemetry sold as 500 mW (not true).
The radios firmware is v 1.12 is it worth to update to 1.13?
Roger Ronald said:
If you have the power on the radio set to a value that's high enough (+30dbm), you're probably exceeding the amount that USB is supposed to supply. USB 1 and USB 2 supply half an amp. USB 3 supplies .9. The RFD 900x can draw one amp peak. With a longer cable.....a marginal situation can cross over to not working.
Try turning down the radio's output power. At 20 dbm, you'd be within spec on all USB versions. You should be able to do ~25-27 dbm on USB 3.0.
I wouldn't risk running at full power from USB for something important!
On a similar note, I know for a fact that powering a RFD 900x from a Pixhawk (especially when the Pixhawk is powered by USB) is a bad idea. My PixHawk had fits and occasionally locked up when I did this. Fortunately, this occurred on the ground and I realized the error of my ways before it became a costly mistake.
I want to use an USB extension before the FTDI cable to put the radio longer and over a pole, but it seems it gets low power and turn on and off continuosly, the extension is active (there is a circuit on the end) and it works with standard 3DR radio.
What is the right way to extend the cable, maybe after the USB-serial conversion or do you know an active cable that actually works?