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

 

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Hi Seppo,

I'm an user of the RFD900+ modem and I'm currently in the process of homologating this product in respect to the brazilian radio emission regulations, so I can use this modem here, but I'm facing a problem that I think you maybe can help me with.

The brazilian regulation allows the use of the 915-928MHz range, similar to that of Australia. 

The problem I'm current facing is that the modem is emiting spurious frequency (909.966MHz) which is not under conformity with the local regulation (which denies the 907-915MHz range).

I'm sending the spourious frequency analysis attached so you can see the problem.

I'm configuring the modem to use the 915-928MHz range, and this problem occure while the modem is finding a link. When it links to the other modem, the problem stop.

Did you already see this problem before?


Thank you in advance.

Attachments:

do you have a circuit diagram of RD900

the RFD900 is not open hardware, so the complete diagram isn't available.

lixiaoming said:

do you have a circuit diagram of RD900

Why are we getting zero support from the manufacturer?

please explain what you've tried, and why you fee that way..?

Mike Mac said:

Why are we getting zero support from the manufacturer?

I have several 900+ units that i run in multi-point mode. The problem is that RSSI does not work. I really like to have TM RSSI recorded by the ground station. They said that it was a know problem and the nest firmware update would fix that bug. That's been way over a year ago. Seams like they spend time selling us new products and not fixing bugs on there current products.

Looks like that Graph above is an example of another bug that's probably existed for a very long time.

.

Hi all. I am using the RFD900+ modems for my high altitude UAV project and am about to conduct a range test. The goal is determine the maximum range afforded by the dipoles and see if I need to use a directional antenna to meet the requirements.

Part of this testing will involve changing some of settings and seeing how the radios perform in our environment, the aim being to find a balance between power consumption, telemetry rate and range.

I have a few questions:

Does anyone have any experience with experimenting with the number of FHSS bins? The obvious choice is the maximum number available in order to minimise the effects of noise. However, is there any advantage in selecting fewer bins? I could see there being an advantage of increased data rate if the dwell time is increased as the number of bins is decreased but I'm not sure if that's how it works. On that note, can anyone tell me what chip is being used so I can get a data sheet and look at how FHSS is implemented and how the number of frequency bins parameter affects the link.

I'll be sure to post back with the test set up and results.

FYI: we're aiming for 50 to 100 km.

Regards,
Mike

Michael,

The radio hops but it not spread spectrum. The number of channels used does not effect the timeslot duration(hop time) so fewer channels won't change data throughput. Best to leave it at 20 for Australia to be compliant. The rfd900+ uses the si1000 radio. The radio firmware is SiK if you want to delve into it's depths. I assume your using standard SiK code that it came with.

Kent.

Michael Shanaher said:

Hi all. I am using the RFD900+ modems for my high altitude UAV project and am about to conduct a range test. The goal is determine the maximum range afforded by the dipoles and see if I need to use a directional antenna to meet the requirements.

Part of this testing will involve changing some of settings and seeing how the radios perform in our environment, the aim being to find a balance between power consumption, telemetry rate and range.

I have a few questions:

Does anyone have any experience with experimenting with the number of FHSS bins? The obvious choice is the maximum number available in order to minimise the effects of noise. However, is there any advantage in selecting fewer bins? I could see there being an advantage of increased data rate if the dwell time is increased as the number of bins is decreased but I'm not sure if that's how it works. On that note, can anyone tell me what chip is being used so I can get a data sheet and look at how FHSS is implemented and how the number of frequency bins parameter affects the link.

I'll be sure to post back with the test set up and results.

FYI: we're aiming for 50 to 100 km.

Regards,
Mike

Michael, if you have good antennas and a tracker. Reaching your target range is not a problem. There are users already who are reporting 100km range for RFD sets. 

So have a good parabolic or yagi antenna on ground and have good finetuned antennas on your plane. Also remember to keep your ground antenna high enough :)

HI,

I would like to know is this connection block could works? The 433mhz using normal apm telemetry.

I need some help with my connection.

Here is my setup. Hexicopter, Pixracer, D4R-II, 5.8Ghz - 600mw VTX

My first choice was to go with Mission Planner, so connected everything. Had telemetry from RFD but I could not get a good stable flight no matter what I tried.

So, I flashed PX4 and tried again. This time I get relatively stable flight (which I believe I can tune), but now no RFD data to QGroundControl. Also when connected this way, my computer suffers severe interference and sends the cursor all over the place on my screen opening windows disappearing just going mental. The green lights are solid (slight flickering) just like it is when I get good connection and data feedback from Mission Planner.

Anyone?

Thanks.

I've just read on Ardupilot they recommend to run a separate 5v power line to the onboard radio. At the moment power is being fed from the Pixfalcon FC. Would this make any difference? It doesn't seem to matter if I connect to Mission Planner, however, no telemetry sent to QGroundControl.

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