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
What about the ECC feature Ikaros, is it working ?
Hi all,
Since I am still struggling to find the solution to my connection problems with my RFD868+ modems I would be very happy for any comments on my setup and questions.
I have a bare minimum setup with two modems close to each other powered by clean 5 volt. The problem is still that sometimes they work (approximately ⅓ of the time I power them) and sometimes they don’t. When they do not work they constantly drop connection every couple of seconds.
If I connect them both to my computer and run a python script that transmit data from one to the other maybe 75% of the packets are lost in the transmission as long as they are not in the “working” mode when all of the packets are received perfectly.
So right now I would like to try another firmware. However, they are running SiK 1.13 which is newer than any firmware I have found on the RFDesign webpage. So if I flash an older firmware I will not have a way back to 1.13.. Does anyone know what have changed in the new firmware and if it is safe to run the 1.12 on the 868+?
Best Regards,
Ikaros, I had a Note about the connections on the plugs for the RFD900+ which has been on my computer for months and I had forgotten about and I just stumbled onto again . NOTE Below.
NOTE:
900+ cable connections
1) for the Cable, TX, RX, +5 and GND are the only lines required, so it should work OK. As long as the cable can supply enough current for the modems then it
is OK.
2) The current generation of APMs don't support flow control (CTS/RTS) so they're not connected.
3) No harm in that case, the modem will automatically switch to the best antenna.
I'm going to try this in next couple of days, I have been having the same problems as you do, And having the RTS an CTS connected on both modems could be what the problem is . You can just remove the two wires from the plugs on both modems.
LOL
I'm a bit of a layman here but I have had connection problems when the modems are close together. Once they are separated I never have any problems. 10 meters is a problem sometimes but the connection problem seems to go away at a greater distance or with objects in the direct line of sight. I am using high db antennas.
Regards,
David R. Boulanger
Hi and thanks for the replies!
“Ikaros Your Power connections are correct in your picture, But where is the Communications Plug Connection ?”
The setup in the picture is without connecting the modems to the Pixhawk or to the computer but the connection between the modems are still constantly dropping. (The green led is blinking, not regularly but now and then)
So I think the issue is independent of the Pixhawk, especially since the problem is still present if I just communicate between the modems when both are connected to my computer with FTDI cables.
However I will try to disconnect the RTS and CTS just in case.
David: That is interesting! I will try the same setup with the modems a greater distance apart
Cheers
I have got the modem on my APM 2.5 set at .5 watts with two 3db dipoles running off the APM. The GCS modem is set at 1 watt with a 5db Omni and a 8db patch with a BEC set at 5 volts. It gives me fits in the house trying to connect sometimes but with separation all is good. Good luck.
Regards,
David R. Boulanger
Yes, that's true - if they're too close to each other and running at higher power, the receiver front end can be over-driven, causing distortion and corrupting the signal. I always ran mine at lowest power when in the house and kept them around 10 feet apart.
I karos Your Power connections are correct in your picture, But where is the Communications Plug Connection ?
Am I missing something?
https://www.dropbox.com/sh/vous5xts2ffqu4v/AACMoX2fIo4EfEEJLSEcaj_K...
I forgot to add, the wire on the pixhawk tele. 1 ,the ground wire, be sure that wire is in pin 1 of the plug that plugs into tho 900+, that will make the common ground - connection between the BEC and Ground.
As for the Positive + wire on the Pixhawk tele 1 you can eliminate that wire, you don't want to power the 900+ from the pixhawk. the BEC will do all the powering for + , it's the common - wire that is most important.
Hi need little input on which antennas to use on a plane
use the stock mono poles or these Flexible
i will using 6dBi Yagi on the ground station
@fred for that Ranger plane it really does not matter what antenna you are using. With stock antennas both on ground and air you can easily get distances over 10km. I would start to look more specific antennas after ranges longer than 15km.
If you plan to use YAGI on ground station you also need to have antenna tracker or you will loose signal fast. Again if you are not planning to go beyond 5-10km. Don't bother to make your life too complex, just use normal monopoles/dipoles or those flexible ones.
You can check Trent's video about our long-range telemetry system with stock antennas (also have comparison to 3DR modems). He flies 5km away with "badly" placed antennas on his plane and still have 99% signal strength.
-
37
-
38
-
39
-
40
-
41
of 65 Next