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        New Product RFD900 - Long range radio modem

#1 Seppos May 26, 2012 12:02 PM

RFD900 - Long range radio modem
 
Update - Multipoint software is now available!, please see our website or RFD900 product page for details.

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/index.php/rfd900

The RFD900 radio modems and accessories are now available at:
http://store.rfdesign.com.au/ (RFDesign - Australia)
http://store.jdrones.com/ (JDrones - Thailand)
https://www.event38.com/ProductDetails.asp?ProductCode=RFD900 (Event38 - USA)

Some of the key features of the RFD900 are as follows:
  • Multipoint link capable for multiple GCS stations and single air station with Mavlink
  • Easy to use, no adaptor or interface boards required
  • Long range >40km depending on antennas and GCS setup
  • 2 x RP-SMA RF connectors, diversity switched.
  • 1 Watt (+30dBm) transmit power, 1dB steps.
  • Air data rates programmable from 4k to 250kbit/s
  • Serial data rates from 2400 to 115200 baud.
  • Integrated Transmit low pass filter.
  • >20dB Low noise amplifier.
  • On board RX SAW filter.
  • Passive front end band pass filter.
  • Open source firmware (V1.x) / tools, field upgradeable, easy to configure.
  • Windows based configuration tools available.
  • Small (30 x 57 x 13 mm), light weight (14.5g including heatsink).
  • 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.
They are 100% compatible with 900MHz Hope-RF based radios (3DR) and similar.
These modems have been flying in various platforms and have demonstrated excellent performance in real applications.

A couple of Outback challenge UAV entries are testing these radios for long range communications :)

RFD900 modems are expected to be available in a few weeks time, before the end of June in production quantities.
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.

Will keep you posted with updates on performance, availability and in the meantime if you would like any more info, let us know!

Seppo Saario
rfdesign.com.au

#2 Seppos May 29, 2012 03:02 AM

A quick update on the RFD900 modems,

Production boards are due to arrive tomorrow (30th May), with a verification build happening towards the end of the week to make sure everything is still within spec.

One of the motivations on designing the RFD900 was the lack of features in existing modems tailored for UAV applications. I had not seen integrated support for antenna diversity which is very beneficial for mobile platforms like UAVs.
The diversity implementation on the RFD900 chooses the best antenna on a packet by packet basis. Having one antenna vertically polarised and the second antenna horizontally polarised (or both at +/- 45 deg) will cover most airframe attitudes reducing the chance of link loss.

Another thing is the attention to filtering - since most RC/UAV platforms operate with a number of radios, being "nice" in terms of reducing noise on other bands (especially GPS, 2.4GHz) is key. The RFD900 has integrated transmit low pass filtering and a chebyshev front end band pass filter on both the transmit and receive path.

Will post more updates on the production boards as they are built !

#3 CenTexFlyer May 29, 2012 09:39 AM

Have a target price?

#4 Seppos May 30, 2012 06:59 AM

Target price for the radios is $90 AUD per modem, pending final manufacturing costs from the contract manufacturer. I am still "convincing" them to reduce their build costs :)

There will be US based and Australian based distributors where modems can be purchased to reduce freight costs and transit time.

Production PCBs have arrived today, running through initial board level testing of the front end filters, LNA and PA. This will confirm that the PCBs have the same characteristics as the ones used prototype builds.

Will post some link results from actual flights shortly to show what kinds of results can be expected.

#5 vau Jun 05, 2012 05:28 AM

This I like the look of - a contender to knock the 9xstream out of top spot maybe.

Do you have latency figures for trasmitting (from the time into the UART on the TX side to out of the UART on the RX side) at 9600? Also what is the receiver sensitivity like at 9.6k - I see -120db suggested for 'low data rates' but does this mean 2.4k?

One of the things i found with the maxstream is that you really have to tweak the settings (retransmit, sleep time, packetisation etc) to get a good telemetry rate down and still have enough space and gaps in downstream transmission to send data back up.

Size and weight look great too.

#6 epyonxero Jun 08, 2012 11:08 AM

Interesting. I like the idea of replacing my GCS 3DR Radio with a system with built in diversity...

#7 Seppos Jun 28, 2012 06:24 AM

RFD900 Modems are available for purchase from the RFDesign online store : http://store.rfdesign.com.au

End of last week we ran through SMT production in Melbourne, Australia and this week we have run through testing and finishing of the radios.

So far they have flown with a few open source autopilots, with nice range..
A datasheet with more detailed specifications is in progress.

#8 Seppos Jul 04, 2012 11:45 AM

RFD900 25km+ range from hilltop to ground level
 
1 Attachment(s)
We did some preliminary tests with the radios at full power, 1 Watt to see what is possible.

This was of course done in the middle of the night in the freezing cold (Winter in Brisbane, Australia).:eek:

One radio was on Mt Cootha, just to the northwest of the city, and the other radio was out of a car window on a wooden stick, connected to a laptop. (at ground level). This is quite nasty for multipath and noise at ground level.
We achieved a bit over 25km with this configuration, at standard air data rate settings (64k).
The picture below shows the two locations where we had a stable link.

The range can be significantly improved with getting the antennas raised above ground level and reducing air data rate which will reduce noise in the receive channel due to narrower filters.

The antennas used were the standard 1/2 wave dipoles at each end of the link.
Next tests will be to an airborne platform, with the GCS antenna elevated a couple of meters.

#9 epyonxero Jul 05, 2012 07:42 AM

Thats pretty impressive with just dipole antennas.

#10 Seppos Jul 26, 2012 01:38 PM

Frozen RFD900
 
1 Attachment(s)
We decided to be cruel and do some extreme testing to see how the RFD900 modems behave under extreme cold conditions. :eek:

The modem was shut down and allowed to cold soak at -60 degrees C. Then powered up to maximum power and had a look at data transfer and connectivity tests. All works just fine.

The modems are available from Australia from the RFDesign web-store, but we are also making arrangements for a wider distribution network. -- Announcements coming soon!

#11 markus123456 Jul 26, 2012 03:04 PM

Quote:

Originally Posted by Seppos (Post 21718526)
Hi All,

I would like to introduce you to a new radio modem that we developed for very long range datalinks!

[snip]

Will keep you posted with updates on performance, availability and in the meantime if you would like any more info, let us know!

Seppo Saario
rfdesign.com.au

Any information on what the achiveable data transfer rates are? I haven't found this info on your website...

Markus

#12 CenTexFlyer Jul 26, 2012 05:37 PM

Quote:

Originally Posted by Seppos (Post 22272432)
The modem was shut down and allowed to cold soak at -60 degrees C.

Shoot! You didn't have to worry about heat buildup did you? How about the other way? We fly in 110F pretty regularly. Keep it all enclosed and toasty in its' own little box.

and +1 on what Markus said.....

#13 flyandi Aug 01, 2012 05:45 PM

This is highly interesting... any info when available in the USA?

#14 narpat007 Aug 05, 2012 06:59 AM

What is the maximum RF baud of the RFD900 ?
It is nowhere mentioned at the product page.

Why two antenna port ? Are both ports transmitting - receiving ? Or one port is only dedicated TX port and the other dedicated RX port.

Generically receivers only have been seen with diversity antenna.
What highest baud the RFD900 would support with APM, without any link loss ?

#15 Seppos Aug 05, 2012 12:28 PM

Thanks for the heads up! - yes, thats a pretty key bit of information - I have updated the product pages and website.

The air data rates supported are from 4k up to 250kbit/sec, these are settable via AT commands. The serial datarates are from2400 to 115200 baud. At the moment, the list of rates and commands are listed on the 3DR wiki from the RFD900 page. I will bring this information into the RFD900 pages for easy reference.

Two antenna ports are used for diversity. The Si1000 has built in diversity support such that it will select the best antenna for every packet. Both antennas get used for transmit and receive, depending on which has the best signal.
If you have a specific requirement for one antenna to transmit, the other to receive, it is possible to modify the open source firmware to do this.

Generally I have used APM 1 and 2, with the default settings, 57600 baud, 64k air data rates. If higher rates are needed, 115200baud, 250k air rates are available. It is also possible to turn off ECC and opportunistic resend to increase throughput. Typical throughput rates for mavlink data are in the order of 80% or so due to overhead from the TDMA framing overhead.

Due to popular demand :D I will undertake some mean HIGH TEMP tests on the modems. One modem will get a good roasting while at full power, maximum data transmission. :eek:. Any guesses on where it will get to before it kicks the bucket ? :popcorn:

Quote:

Originally Posted by narpat007 (Post 22360162)
What is the maximum RF baud of the RFD900 ?
It is nowhere mentioned at the product page.

Why two antenna port ? Are both ports transmitting - receiving ? Or one port is only dedicated TX port and the other dedicated RX port.

Generically receivers only have been seen with diversity antenna.
What highest baud the RFD900 would support with APM, without any link loss ?



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