Hi All,

I'm looking to get a 3DR telemetry kit for my APM 2.5 and I'm not sure what the best frequency is for NZ conditions - 915 or 433 Mhz? It looks like both are supported here and I understand that you get greater range with 433 but that there might be more interference there from portable phones, etc.? Also, are the standard aerials good enough or would some sort of circularly polarised antenna be better?

Any advice would be much appreciated.

Cheers, Andrew 

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  • Jack - we want to set up a system to operate the MavLink on the proper frequency in NZ too.  Did you leave your 433 Mhz mavlink set up as default or did you change the frequency?  If you changed the frequency, how did you do that?  I read https://code.google.com/p/arducopter/wiki/3DRadio#Support_for_diffe...  that confirms the frequency CAN be changed, but I must be overlooking HOW to change the frequency.  Can you please point me to the HOW TO change the correct frequency of the MavLink for NZ?


    Bret C

  • Under Radio Spectrum Managements General User License, the maximum allowable transmit power between 915-928mHz is just over 3mw. Between 433.05-434.79mHz you are allowed just over 25mw. You have a much larger band width at 915mhz but much lower allowable output power. I use 433mHz myself and it is perfectly adequate for my needs where I typically fly within a couple hundred meters.
  • Lower frequencies are always better than higher frequencies. Lower freq however require larger antennas but they give more range on the same power and have better object penetration abilities. The problem with higher frequencies (eg 5.8g) is they are very poor when items like trees get in the way. Its not a coincidence that higher freq were selected for items that require low range like cordless phones and wifis (5.8g) while mobile networks (900mhz etc) have much lower frequencies

  • Hi Andrew,

    I have been using the 915 mhz aerial for a year now with no issues. Gets reasonable range around 800m from GS. 

  • Hey Andrew, I am from Nz too, did you ever find out your answer? I was looking to get one too but was unsure on the frequencies.



    • Hi Bret,

      I believe I did configure the max and min frequencies using the AT command procedure described on this page:


      There is a GUI in mission planner you can use to configure many parameters also described on that same page. Watch the power level is correct!

      • Thank you Jack:

        Bret C

  • Also, the terrain I'm going to be flying over is mostly rural and possibly a bit hilly.

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