HM-TRP 868 vs. 3DR Radio Config 0.9

"Homemade" HM-TRP 868 MHz identified as:

SiK 1.6 on HM-TRP


In tool for Min Freq default value is 868000, for Max Freq is 869000, BUT in both dropdown lists I have:










Is this correct?

PS. Same in Mission Planner...

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  • I have the 915MHz radio from the RCTimer APM 2.5.2 kit, and it has a different range. Just load the default.  I see Mission Planner 2.0.14 no longer has an option to upgrade the 3DR radio firmware, or it just won't upgrade this one.

    How are people doing the upgrade to 1.9 now?  I'm on 1.6, and I don't think that will transmit data -- mine isn't anyway!

  • I have a question .....  using a telemetry of 433 MHz can I change frequency to 900MHz  internally using firmware or this is a hardware feature ... the datasheet says that "Frequency range = 240–960 MHz"

    so are there variant of the IC itself for different frequency ranges or this is a single IC

    • I have just found this function in radio.c 



      I believe this is the answer am I right

  • Greetings,

    When I inquiry the RSSI my HM-TRP868M using "AA FA 87", it shows 00.

    According to data sheet, this is > -100dbm.

    Is this normal?


    • That would be 1/2 watt!  That's a honking radio there.

      • Check your calculation again...

  • Developer

    Hi Marcin,

    I think you will need to use the AT interface in a terminal program to set the frequencies. The 3DR tool that Michael wrote is meant for the 3DR radios, which don't (yet!) come in a 868 variant.

    See the wiki page for information on the AT interface.

    Cheers, Tridge

This reply was deleted.


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