Hi All,
I would like to introduce you to a new radio modem that we developed for very long range datalinks!
http://rfdesign.com.au/RFD900.php
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:
http://store.rfdesign.com.au/rfd-900p-modem/
Seppo Saario
rfdesign.com.au
Replies
Medium gain omni-directional antenna covers the GSM 900, GSM1800 / UMTS and LTE frequency bands.
I have this antenna mounted on my project and am in the process of ordering a pair of RFD 900+ or RFD 868+'s.
Can some one please tell me if my current antenna is suitable for the RFD modems?
I am assuming that as the antenna's that come in the RDF900+ Bundle are 3dBi that my 5dBi will give me better range?
I was planning on using a 2dBi as the other antenna on the project.
The spec's of the PCB antenna are as follows:
Frequency in MHz:
860-980
1710-2170
2500-2700
Gain (Max): 5 dBi
VSWR: < 2.5:1
Feed Power Handling: 10 W E-Plane 3 dB
Beamwidth: 40° (± 5°) H-Plane 3 dB
Beamwidth: 360°
Front to Back: —
Nominal Input Impedance: 50 Ohm
Polarisation: Linear Vertical
Also if this antenna is suitable for the RFD modems would there be any better performance between the RFD900+ and the RFD868+?
Hi everyone and thanks for the comments!
However, I still have the same problem. Today I tried lowering the output power to 1 dBm on both modems. I measured the voltage on the supply pins with an oscilloscope and compared the results to the 20 dBm setting. The voltage was more smooth with less spikes and drops. No improvement though. I then added one 100uF capacitor to both modems. Still no improvement, the connection is still dropped regularly.
However, I have done one observation during all the testing. It seems like the radio may operate in two distinctive modes. Either they are working or not working for the entire session until they are repowered.
I.e. if I connect one modem to the computer and the other to the Pixhawk and then power the Pixhawk sometimes everything is fine. But if I then repower the Pixhawk the connection starts to drop every 5 seconds and keeps on doing it until I repower again, and I usually have to repower several times to enter the “working” mode. Also when in the “not working” mode the amount of data that is received in QGC is much less.
Thanks for any further comments.
Best
Ikaros, Is your 900 powered with a BEC or from the Pixhawk ? I use a 5amp BEC on the Base Station and Pixhawk.
With the power that the 900 uses it best to use a BEC to power it.
Hi James,
Yes I have tried powering both the ground and remote RFD868+ with 10amp BEC:s unfortunately with no improvement.
Check with RFD and see if they may have a firmware update, use the RFDtools to do update.
I had this problem the 900's and I had to do a update. to 1.12 firmware.
Check your wiring on the drone with the Pict8.jpg I sent, I also had to rewire the plug on the RFD900+ plug. If your using the USB cable that came with the package you should not have any problems with Base Station connections.
Change Log?
Is there a change log that explains the differences in the various versions of RFD900 firmware? I just got another RFD900+ from Event38 and it came with V1.9 firmware. It links ok with my old 900 on the ground station. I don’t want to risk an upgrade unless I know that it will be of some benefit to me.
.
@Mike,
I have two of the Event38 RFD900 modules running v1.9 and they communicate just fine between each other but they will not communicate with my 3DR 915MHz telemetry radios.
Event38 told me to uncheck the ECC box on both the RFD900 and the 3DR modules and then they should communicate. They also told me that they have contacted RGD about the communication issue with the 3DR telemetry radios.
Regards,
TCIII AVD
The two 900+ I bought had 1.9 on them and they wouldn't boot, I upgraded to Firmware-1.12 and they booted fine.
If you do ever upgrade use the RFDtools-1.6 to do so.
I'm communicating fine, don't know the difference in the two versions.
But there is a reason they came out with a new version.
Hi James,
Can you post a picture of your Base station RFD900 powered by the BEC and the data cable to USB.
I want to make sure to have done the data wiring right!!!
Cheers
Goto this location to see Pictures of the install of the RFD900+ and Pixhawk, 8 Pictures.
Pict8.jpg is a picture that shows wiring between 900+ and Pixhawk , when using a BEC it changes in relation to +5v and Ground -
The +5v wire is eliminated and Ground - is connected to the large Plug at pin 1 to give you common ground between Pixhawk and RFD900+
See pictures
https://drive.google.com/drive/folders/0B3XG-9FznyywflNHS3BDZ1cxX0J...
Why won't this website allow you to upload more than 3 files (pictures) ?
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