RFD900, RFD900+ - New long range radio modem

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

 

Views: 108353

Reply to This

Replies to This Discussion

There is a parameter to keep the plane from speaking for a delay period. Set the TELEM_DELAY parm to the number of seconds you desire. You’ll see “no input data” for that length of time, but it then starts up. I had problems with MinimOSD failing until I delayed the start. I got about 90% about 90% success at 7 seconds…so now I have the daly set to 15 seconds for my plane. There’s some sort of sequencing problem that this must fix.

Thomas Stanley-Jones said:

Isn't it always after you ask the question that the answer presents itself. We've figured out that the radio can't handle a constant stream of data when it boots up. If we wait to plug in the data wire until moments after booting up, everything is fine. It's the radio in the relay that's transmitting to the basestation that's giving us problems. The UAV is constantly chattering so it's as if it can't handle the noise when it wakes up in the morning. How would you set up this circuit so this problem isn't encountered? I can only think to have a switch that you turn on after the battery is plugged in.

I've googled for hours, but I still can't find an answer.....

How many PPM channels are support by the RFD900x?  8 or 12 (or something else?)

I have been using the PPM over RFD900x for a while.

I think that there are 8 channels passed through the RFD900x - I have not tried to put more through.

Here is a view of the signal coming out of the UAV end of the link.

https://photos.app.goo.gl/4njbjv7YHnPtZJgc2
well that's bit sad if its only 8 my diy uhf module has 16 with mavlink

Michael,

Thanks for the scope shot. I'll note that it appears to show 9 channels and I have heard other people indicated that's the limit for FRSky.

But, I don't think it's definitive for the RFD900x radio yet....if you only put 8 (or 9) channels in, you'll only get 8 (or 9) out. It's possible that the radios may accept more channels and output them on the other side of the link.

Most RC transmitters seem to only send 8 or 9 channels of PPM. They can send more channels with other protocols (e.g., CSRF, SBus). Some receivers scan definitely output 12 ch PPM (e.g. TBS Crossfire), but their ground comm protocol when their radio is plugged into an FRSky side is CSRF....since the limit would be 8 (or 9) channels. Even if I have to mux in the other PPM channels on the ground after exiting the TX, I can deal with that.

Question for Fred F is, what DIY UHF radio are you using? Some of them sound good, but they don't fully support MAVLink up and down. I want to be able to send ground station commands and parameters up...and reliably get all the telemetry down.TBS Crossfire supports this....but I keep getting telemetry dropouts every five to 10 minutes or so...which breaks the MavLink connection.

Dragonlink v3 does all of that with full bi directional Mavlink. 12 channels. If you get the 1.5W RX you can also have 40km of range. Not DIY though. Google ULRS if you want DIY.

Roger Ronald said:

Michael,

Thanks for the scope shot. I'll note that it appears to show 9 channels and I have heard other people indicated that's the limit for FRSky.

But, I don't think it's definitive for the RFD900x radio yet....if you only put 8 (or 9) channels in, you'll only get 8 (or 9) out. It's possible that the radios may accept more channels and output them on the other side of the link.

Most RC transmitters seem to only send 8 or 9 channels of PPM. They can send more channels with other protocols (e.g., CSRF, SBus). Some receivers scan definitely output 12 ch PPM (e.g. TBS Crossfire), but their ground comm protocol when their radio is plugged into an FRSky side is CSRF....since the limit would be 8 (or 9) channels. Even if I have to mux in the other PPM channels on the ground after exiting the TX, I can deal with that.

Question for Fred F is, what DIY UHF radio are you using? Some of them sound good, but they don't fully support MAVLink up and down. I want to be able to send ground station commands and parameters up...and reliably get all the telemetry down.TBS Crossfire supports this....but I keep getting telemetry dropouts every five to 10 minutes or so...which breaks the MavLink connection.

Fully support MAVLink up and down at 19200 at 1W each way
same module set one as RX and the other as TX

Hi,
The 900x supports up to 16 channels of PPM passthrough.
Cheers,
Seppo

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...

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

GCS
NodeID : 1
DestID : 3 (Directed to Rover)

Relay
NodeID : 2
DestID : (what should this value be? 65535)

Rover
NodeID : 3
DestID : 1 (Directed to GCS)

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

  1. Run an FRSky XSR receiver in the plane and output 8 channel CPPM. Select between the CPPM stream from the RFD900x (12 channels) or the XSR (8 channels) using a RFD900x GPIO pin. I'm not sure what happens to the 4 other channels when they aren't getting into the CPPM stream...but if they hold on their last input, that would be fine (I don't care about switching my lighting on/off or my OSD screen selection during takeoffs or landings). If I do this, I get some nice redundancy on the R/C control link. I can also send back FRSky telemetry thru the XSR and add some additional telemetry redundancy.
  2. Run an FRSky XSR receiver in my groundstation that I can use to drive the RFD900x on the ground. With a SPDT toggle switch, I can select between the trainer cord and the XSR. However....while I'm using the XSR, I'm at the mercy of two links and I'd need a MAVLink converter to get telemetry to the FRSky TX.

SBus to CPPM conversion sounds like a reasonable option, but it is one more point of failure.

Andrew Ferry said:

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...

Hey everyone,

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. 

Reply to Discussion

RSS

Groups

Season Two of the Trust Time Trial (T3) Contest 
A list of all T3 contests is here. The current round, the Vertical Horizontal one, is here

© 2019   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service