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

Replies

- Ivan R > Dan Ho August 27, 2015 at 4:20pm
  
  where exactly did you have to install the capacitor at? which cable and how? thanks
  - James tate > Ivan R August 27, 2015 at 5:45pm
    
    Ivan, He stated supply wires, meaning +5 an - .
    
    What he is saying is a good Ideal, if you have long + an - wires to the 900 it is easy to pick up static electricity and that can cause problems.
    
    Put the capacitor right at the plug of the 900 across + an - , the capacitor most likely will have a - sign at one lead , solder that to the - power wire and the other lead of capacitor to the + wire.
    
    If your not aware, capacitors are design to knock down static pulses.
    
    You can most likely pickup a 100uf 15volt Cap.at Radio Shack or a local Electrical Supply store.
    
    I haven't done that yet either, but I will get right on it tomorrow.
    
    CAP.AT steht zum Verkauf
    - Dan Ho > James tate August 27, 2015 at 6:40pm
      
      You're right about the cap installation, James.
      
      If there's too much voltage drop when the modem transmits and the voltage spikes below something like 4.9V, it may upset it. You cannot tell just by using a voltmeter - you need an oscilloscope to see the fast voltage transients. But no need to mess with an oscilloscope - just install the capacitor or connect a sufficient power supply with very short, thick wires to find out if it makes the problem go away. A 10 volt cap is sufficient and probably 47uF would be ok, depending on the length and size of your +5V & GND wires.
      
      But, again, you can also quickly and easily check if this is the problem simply by setting the transmit power to its lowest setting because then the voltage drop should be negligible - even if the wires are long and thin.
Ikaros August 27, 2015 at 6:25am

Hi,

Thank you for the answer. However, unfortunately I have still not been able to make any of my RFD868+ modems to work and would be happy for any further input. Is anyone using the RFD868+ successfully?

I checked the firmware on my modems and they are SiK 1.13 (which is newer than the one that may be downloaded from the RFDesign website)

Today I tried two 3DR radios and connected them both to my computer. The green led is solid green on both of them and the communication works perfectly. (I had two cutecom consoles open and were sending messages back and forth with no problem)

But if I instead connect two RFD868+ modems the same way the connection is constantly dropped every now and then. I set up the modems the same way as the 3DR radios as follows:

0:FORMAT=26

1:SERIAL_SPEED=57

2:AIR_SPEED=64

3:NETID=30

4:TXPOWER=20

5:ECC=1

6:MAVLINK=1

7:OPPRESEND=1

8:MIN_FREQ=868000

9:MAX_FREQ=869000

10:NUM_CHANNELS=10

11:DUTY_CYCLE=100

12:LBT_RSSI=0

13:MANCHESTER=0

14:RTSCTS=0

15:MAX_WINDOW=131

I would really appreciate any help

Best

Carl
Admin

Thomas J Coyle III August 26, 2015 at 1:26pm

Hi All,

I recently purchased the Event38 RFD900 telemetry radio bundle to compensate for the limited range of my existing 3DR 915MHz telemetry radios.

I was under the impression that the RFD900 radio is compatible with the 3DR 915MHz telemetry radios if the parameters are set to the same values and the same check boxes checked. I have a friend who's RFD900 radios does communicate with his 3DR telemetry radios.

Unfortunately I found out that that is not necessarily true in all cases.

I tried using one of the RFD900 radios to connect to the 3DR 915MHz radio on my rover and could not make a connection.

Both radios had their green leds on and I could see both radio's red leds flicker.

Both the RFD900 and the 3DR radios are running firmware version 1.9.

I plugged each telemetry radio into my laptop and used MP to verify that the parameter settings and check boxes were identical to each other except for one parameter called "format".

The RFD900 radio's format parameter value was found to be 26 while the 3DR radio's format parameter was found to be 25.

It appears that a RFD900 radio with a format parameter value different from the 3DR radio's format value will not communicate with each other.

I then verified that the two RFD900 radios would communicate with each other since they both had the same format parameter value of 26.

The format parameter is not adjustable in the Mission Planner's telemetry radio screen and neither in the 3DR telemetry radio configuration application.

Is the format parameter only adjustable at the factory or can I use the RFD900 Modem Tool to adjust the format parameter value or will updating the existing RFD900 firmware resolve the issue?

Though I suspect that the format parameter value is factory set and not adjustable.

Comments please!

Regards,

TCIII AVD
- Marc MERLIN > Thomas J Coyle III March 29, 2016 at 4:03pm
  
  Hi Thomas, did you ever resolve this? I have the same problem between a 3DR compatible radio and an RFD900+
Richard Sterling August 26, 2015 at 12:46pm

Hi All,

Has any body tested the new RFD868+ ?

This may be a stupid question but will the 1w 868MHz have the same range as the RFD900+ (1w)?

Will the 900MHz GSM band interfere with the RFD900+ or vise versa?

Cheers,

RS
Ikaros August 18, 2015 at 6:01am

Dear all,

I have a connection problem with my RFD868+ modems and I am looking for some input on how to solve the issue.

- If I connect two RFD868+ to my computer via FTDI cables the connection is solid between the two.

- If I instead connect one of them to a Pixhawk (on TELEM1 connector) and monitors the connection in QGC the connection is lost every 3rd or 4th second.

- The connection drop is very regular, but the connection is regained after approx. 2 seconds.

- It does not matter if I power the pixhawk via USB or 5V BEC.

- It does not matter if I power the radio modem directly from the Pixhawk or from 5V BEC.

- It does not matter if I replace both the RFD868+ modems with a second pair.

- If does not matter if I lower the amount of data transmitted from the Pixhawk.

- If I instead replace the radio modems with 3DR 433 MHz modems the connection is solid without any drops.

The configuration of the RFD868+

0:FORMAT=26

1:SERIAL_SPEED=57

2:AIR_SPEED=64

3:NETID=25

4:TXPOWER=20

5:ECC=0

6:MAVLINK=1

7:OPPRESEND=0

8:MIN_FREQ=868000

9:MAX_FREQ=869000

10:NUM_CHANNELS=10

11:DUTY_CYCLE=100

12:LBT_RSSI=0

13:MANCHESTER=0

14:RTSCTS=0

15:MAX_WINDOW=131

The configuration of the 3DR 433 MHz modems

S0:FORMAT=25

S1:SERIAL_SPEED=57

S2:AIR_SPEED=64

S3:NETID=25

S4:TXPOWER=20

S5:ECC=1

S6:MAVLINK=1

S7:OPPRESEND=1

S8:MIN_FREQ=433050

S9:MAX_FREQ=434790

S10:NUM_CHANNELS=10

S11:DUTY_CYCLE=100

S12:LBT_RSSI=0

S13:MANCHESTER=0

S14:RTSCTS=0

S15:MAX_WINDOW=131

I would really appreciate all help.

Best Regards
- Ikaros > Ikaros August 20, 2015 at 1:18am
  
  I am trying to find the source of the connection issues, do someone know the answer to the questions listed below or where I can find them?
  
  1) Sometimes when I power up the modems the green led is completely off and the red is constant on. I think this means firmware update mode, why is this happening?
  
  2) When the connection is lost the green led on the modems start to flicker, is this "normal" behavior for packet loss or is it an indication of something else?
  
  3) According to the manual you may use the modem with one antenna. Do I need to terminate the second antenna connector with a 50 Ohm impedence or just leave it open?
  
  Thank you very much,
  
  Regards
  - James tate > Ikaros August 22, 2015 at 1:59pm
    
    1) If the Red led stays on you will have to update the firmware, goto RFDesign.com and Download;
    
    RFDtools-v1.6.zip
    
    RFDsik-v1.12-RFD900p.ihx (Latest Firmware)
    
    Install the RFDtools and put the RFDsik-RFD900p.ihx in the same folder/directory, and run the RFDtools and install the Firmware from the RFDtools.
    
    2) the green led On it is connected between the Base and Plane modems.
    
    3) the modems will work with one antenna and you do not need to terminate the other antenna connection, but it is best to use both antenna's
    
    You'll have to connect each Modem to the usb cable to Laptop to update Firmware, most likely the old firmware will be 1.9 version.
    
    At the bottom of the RFDtools there are three boxes that needs to be checked,
    
    ECC
    
    opResend
    
    Mavlink
    
    If you are connecting to Pixhawk.
    
    I could not get the mavlink to connect using MissionPlanner, I had to install APMplanner .

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