The Real Specs and Ranges for 3DR Radios!

The product page for the 3DR radios is full of bogus specs!  Could you please post the REAL specs?

For example, the page claims "Receiver sensitivity to -121 dBm".  That is the spec for the SiLabs chip radio.  HopeRF lists the specs for their radio module as significantly less sensitive, and obviously you can't obtain the spec of the module when used within another product, like the 3DR radio.

Also, what's with the range claims?  I see you've changed it at least once, but why not make a realistic range claim.  These radios should do around 8 km.  So why only say one or a few?  Have you really not properly tested them over a few km?

Also saying "with Si1000 8051 micro-controller and Si4432 radio module" sounds like the product page writer may not have a good grasp of the hardware.  It has one Si 1000 radio chip in it.  I guess you can argue that statement is sort of true, but it certainly could cause someone to misunderstand and think it has two chips on board.

Don't take this as a rip.  I just see a lot of radio retailers out there that either flat out lie about the specs or have such a poor understanding of the technology that they mistakenly put wrong specs.  I don't think DIYdrones is either of these, so I thought I'd offer some constructive criticism to help you guys get going.

I also kind of feel responsible since I recommended using these chips in a radio design in several posts last Sept..  So if you need any help, just ask.

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  • Hi , i got 2 pairs from Bangood 915Mhz , i can't  do more than 50meters with the provided antennas...Are they bad?What is wrong?

    My ground antenna is with me ,1.2 meters from the ground3702350118?profile=original, not far 10cm from the RC transmitter

  • MR60

    How do you place your ground antenna on a stick high off to the ground ? What king of USB extension cable do you use for that ? Is it shielded ? Is it a powered USB extension cable ?

  • T3

    Probably a dumb question, but I couldn't find the answer anywhere.  For the stock antennas that come with the 3DR, which way should they face?  Right now, I have them both pointing up.  One comes out of the laptop and points up, and one is mounted pointing up on the copter  Thanks!

  • Moderator

    I've measured the active element of the 3DR 433MHz antenna at 42mm (1.65") but it's coiled (see pic). 160mm should be quarter wave for 433MHz so does the coiling make 42mm equivalent to 160mm, would uncoiling it make it better?


  • Just as a FYI. Today I was able to go out and get a good solid 1km out of the telemetry set. This is up from the sketchy signal I was getting at 500 meters. On the ground I'm using a 3dBi antenna from L-Com..

    In the air I'm using the standard stock antenna. Both radios were set to an air speed of 24, down from 64. I'll test out to 1.5km next weekend. 

    900 MHz 3 dBi Rubber Duck Antennas
    900 MHz 3 dBi Rubber Duck Antennas -
  • Would an ezUHF conflict with the 433MHz module? It's possible to change the power level in the firmware or only with external amp?


  • I just built a simple inverted V antenna to fly on the plane.. I'll keep the original duck on ground and see what effect it has.  I did a little walk around the house and the signal was obviously better with the new built antenna. Windy and cold here in Maryland so it may be awhile...



  • Moderator
    So does this mean that the xbee 900 system gives better range? Even if it does cost more?
  • Today I went out and setup a flight that would take me out about 700 meters. The ground station radio unit was placed on top of my SUV's tailgate with the antenna pointing skyward. The Ground Station had a 3dBi antenna placed on it from LCOM..

    The radio in the plane was a standard stock antenna with default settings. The antenna points skywards... I'm running 900mhz in this setup. Looks like I'm getting about 500 meters before my signal degrades. I'm attaching my radio settings if anyone has any suggestions to get a bit further out. Not going to rule out crappy placement on top of my car. I might go out and get a pole and a tripod to mount the radio on. 



  • I get 5200-6200ft LOS range in air consistently with 3DR 900Mhz version and stock antennas in a dense suburban environment. 

This reply was deleted.


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