RFD900, RFD900+ - New long range radio modem - Discussions

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

Hi Seppo, fantastic work on the RFD900. My name is Horace and I am part of a Jamaican UAV dev team working on an ambitious program which involves the use of UAVs in anti IUU(Illegal, Unregulated and Unreported) fishing. We are currently working with the techpod airframe as the airframe of choice for trials to see just how effective these systems can be.

The area we want to cover is huge: 2/3 the size of the island of Jamaica in an area in the center of the Caribbean basin just south of Jamaica called the Pedro banks. The target area for surveillance in the Pedro banks is Northwest Ridge , a relatively shallow bank located on the southwestern portion of the Pedro banks, this is where most of the illegal fishing takes place. This bank is approx. 110km from Middle Cay which is a small island where fishermen and the coast guard is based. The closest 'island ' to northwest ridge is southwest rock located 63km away. Southwest rock is literally a rock with a mast on it...

My plans:

We need to be able to reach northwest ridge from middle cay, my plan is to mount a repeater on southwest rock that would amplify the signal being sent by the RFD900 radio located at base station on middl cay. This would allow diect UAV flights from middle cay to northwest Ridge, maintaining radio connection along the way.

How could I set up such a network?

Replies

Horace Cunningham August 30, 2014 at 8:14pm

Hi Seppo, fantastic work on the RFD900. My name is Horace and I am part of a Jamaican UAV dev team working on an ambitious program which involves the use of UAVs in anti IUU(Illegal, Unregulated and Unreported) fishing. We are currently working with the techpod airframe as the airframe of choice for trials to see just how effective these systems can be.

The area we want to cover is huge: 2/3 the size of the island of Jamaica in an area in the center of the Caribbean basin just south of Jamaica called the Pedro banks. The target area for surveillance in the Pedro banks is Northwest Ridge , a relatively shallow bank located on the southwestern portion of the Pedro banks, this is where most of the illegal fishing takes place. This bank is approx. 110km from Middle Cay which is a small island where fishermen and the coast guard is based. The closest 'island ' to northwest ridge is southwest rock located 63km away. Southwest rock is literally a rock with a mast on it...

My plans:

We need to be able to reach northwest ridge from middle cay, my plan is to mount a repeater on southwest rock that would amplify the signal being sent by the RFD900 radio located at base station on middl cay. This would allow diect UAV flights from middle cay to northwest Ridge, maintaining radio connection along the way.

How could I set up such a network?
- Seppo > Horace Cunningham September 9, 2014 at 9:58am
  
  Hi Horace,
  
  That certainly sounds like an interesting application..
  
  The only practical way of setting up a repeater network as you describe would be with 2 modems back to back at southwest rock - each modem there would have it's own network ID.
  
  The aircraft could connect to southwest rock always.
  
  The southwest rock repeater would connect to the GCS with a high gain yagi.
  
  There are a lot of things that could be done with multipoint and relaying data, but, that has not been implemented yet.
  - Horace Cunningham > Seppo September 9, 2014 at 10:37am
    
    Thanks for the info Seppo.
    
    One concern I have about using a yagi on the repeater rather than a high gain dipole is that the aircraft would lose gain if it is not directly aligned in the transmission beam of the repeater. For example:
    I have aircraft x operating 40km directly north of the repeater on southwest rock on a search and rescue mission, the repeater's yagi antenna is pointed towards northwest ridge which is located west north west of southwest rock. The wave width of the yagi's beam is roughly 14 degrees which means the aircraft would be getting very low gain at the location north of the repeater.
    
    A dipole I think would be the only asset that can allow this multiple directional connection... However, how high a gain dipole can I get? Don't think size will be an issue
    
    Thanks for your help again, would love if we could have more regular/direct contact so that we can get more information going between us.
Shameem Ferdous August 19, 2014 at 5:52am

I can't see any LEDs. Mine are from Jdrones.
Shameem Ferdous August 16, 2014 at 7:25am

Hi,

I just got my RFD900 modems from JDrones. They are cased in physically different casing than that of rfdesigns versions. And the air module comes with a telemetry cable whose connector does not snug fit the telemetry port on my APM2.5 board. I did not try to push it hard fearing something may get broken. However I was powering my board with usb cable and not by UBEC. Though I could read the ground module settings in config tool I could not connect the two modules in any way. I was wondering whether is it because of apm being powered by usb. Another problem with JDrones modems are, they have no status LED, which leads to confusion whether they are powered on or not. However I still finding ways to connect both modules with each other. Hope I get some heads up from you guys.

Thanks
- Seppo > Shameem Ferdous August 18, 2014 at 8:15am
  
  Hi Shameem,
  
  Were you able to get the modems to link up OK? - If you can see the LEDs on either modem, you can see if the modems have connected between each other by a solid green LED. If the green LED is flashing, they are not linked and most likely one modem is not powered up.
  
  Seppo
  - Horace Cunningham > Seppo August 30, 2014 at 9:40pm
    
    I would also like to know if the plans/schematics for the RFD900 is available
- iskess > Shameem Ferdous August 16, 2014 at 10:50am
  
  You cannot use telemetry if you are hooked up via USB.
Seppo July 20, 2014 at 9:00am

Hi!, Just a quick update - we have a bunch of new cables in stock to connect RFD900, and RFD900u's to both APM2.5 and Pixhawks in stock! - This should make connecting things up easier :)
Seppo July 15, 2014 at 5:27am

Dynamic power control available for Beta testing

It has been a very long time since writing - we have been keeping busy with all kinds of project work and when we have a chance, designing new hardware

We have some new software features which might be of interest when looking to save power --- Dynamic power control !

When it is enabled in V1.10 (beta), the modems will monitor the RSSI levels, and adjust their transmit power to achieve a target RSSI level.

The details are in the "Software manual", at: RFD900 Software manual (Page 8 has the goods!)

Quick summary:
ATR0=255 (this disables Dynamic power, and sets modem to maximum permissible power set in ATS4)

Starting point values:
ATR0=150 (target RSSI)
ATR1=20 (hysteresis, before a power change is commanded)

It is still in Beta, so if you have a chance to check it out and feedback your comments, it would be much appreciated.

Seppo

of 61

This reply was deleted.