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

Dear all,

I have two questions regarding the ¼ wave length monopole antenna that comes with the RFD868+ and ground plane. Thankful for any comments!

- The antenna:

http://store.rfdesign.com.au/antenna-900mhz-2dbi-right-angle-monopo...

1) The antenna needs accoring to the description a ground plane for optimal performance, but how do you usually mount the GND plane when the connector is 90 degree turned?

2) We intend to use the RFD868+ radio modem on a flying wing for long range telemetry and I am considering different antenna options. My question is, if I place the monopole antenna facing downwards and add a ground plane, then I will gain in antenna performance (compared to no GND plane) but this will also restrict the radiation to the lower part of a sphere centered at the airplane. So as soon as I am in a rolling motion turning towards me I will have zero connection since the ground plane is between the transmitter and receiver. Is this something any of you have experienced and if so how do you usually mount the antenna and the ground plane to avoid it?

Thanks!

Replies

- Ikaros > Dan Ho August 11, 2015 at 12:55am
  
  Hi Dan,
  
  Thank you for the comments. I will start without ground plane and see if I can improve the performance later after some range tests.
Ikaros August 9, 2015 at 11:28pm

Dear all,

I have two questions regarding the ¼ wave length monopole antenna that comes with the RFD868+ and ground plane. Thankful for any comments!

- The antenna:

http://store.rfdesign.com.au/antenna-900mhz-2dbi-right-angle-monopo...

1) The antenna needs accoring to the description a ground plane for optimal performance, but how do you usually mount the GND plane when the connector is 90 degree turned?

2) We intend to use the RFD868+ radio modem on a flying wing for long range telemetry and I am considering different antenna options. My question is, if I place the monopole antenna facing downwards and add a ground plane, then I will gain in antenna performance (compared to no GND plane) but this will also restrict the radiation to the lower part of a sphere centered at the airplane. So as soon as I am in a rolling motion turning towards me I will have zero connection since the ground plane is between the transmitter and receiver. Is this something any of you have experienced and if so how do you usually mount the antenna and the ground plane to avoid it?

Thanks!

Antenna 900MHz 2dBi Right Angle Monopole (RPSMA)

RFDesign designs and manufactures the Antennas, RF Electronics and the RFD900 radio modem
juan pablo gayoso August 6, 2015 at 4:42pm

I have a RFD900 modem Bundle working in my UAV. Now, I am build a new DIY UAV, so my question is: can I use my old RFD900 modem as ground station, and binding with new RFD900+ version in the UAV. It mean that my present Ground modem will be working with both UAVs, one at time?...it will be possible?
Ikaros August 6, 2015 at 8:51am

Hi,

I have another question regarding the AT commands. Now when I connect the FTDI cable to the modem and write '+++' I get 'OK' back. However, then when I try any command, e.g. ATI5 I only get the exact same letters back and no information. Is this normal operation and I am missing something?

Thanks in advance!

Regards,
- This reply was deleted.
  - Ikaros August 9, 2015 at 2:35am
    
    Thanks again :) now it works!
Henri August 5, 2015 at 10:54am

Much better link than the 3dr modem.

Seppo: I do have a number of RFD900 and they all perform very well except one.

As I was setting the channel number and other various parameters through mission planner, the on board LED got solid red and nothing I have tried changed this?

It is the new version (black PCB with version I written).

I even downloaded RFDtools V 1.5 but it looks like this one refuse to communicate.

What should I do?

Thanks and regards

Henri
- Henri > Henri August 6, 2015 at 5:38pm
  
  Perhaps Seppo took long holidays in a paradise island?
  
  :-)
  
  Henri
  - juan pablo gayoso > Henri August 6, 2015 at 5:45pm
    
    yep, in my case the modem seen not connect with RFDTools, or 3DRRadio.exe, but I realiced that the USB port recognize the modem. So, I tried to update the firmware, as read in some part, and, miraculously, the RFDTools worked straight. After that the modem return to green light........the key was read that the solid Red light mean Firmware update status.....was my case
- juan pablo gayoso > Henri August 6, 2015 at 5:01pm
  
  i am not an expert but I had a similar problem, the solid red means Firmware Update state. I clicked the Update button and enter in this state. The solution was update the Firmware with the same Firmware version. Please, use that as reference, I am not an expert, as told you....luck :)
  - Henri > juan pablo gayoso August 6, 2015 at 5:36pm
    
    @juan : Thank you for your comments.
    
    As the comms between the modem and the USB interface look completely non responsive, that didn't work for obvious reason.
    
    Placing another RFD900 modem on the same laptop / Usb interface works perfectly.
    
    Henri

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