HM-TRP problems with HK 433 modules v/ 3DR modems


this is my first post here, so be gentle ;)

I have a setup where I'm using HM-TRP modules with Sik 1.9 firmware (downloaded with Silabs programmer). I also have a number of 433 modules from hobbyking, and a bunch of modules from 3DR.

I see some problems between different configurations here.


1) HK module and 3DR talks ok with each other

2) One of my HM-TRP raw modules will talk with HK module and with 3DR module

3) Another of my HM-TRP raw modules will NOT talk with HK module but works with 3DR module

4) The two HM-TRP raw modules will talk with each other ok


Bonus info: The raw module in 3) was changed to another module, that one would very sporadic connect with the HK module (did not test with 3DR but assume it would have worked ok)


So, basically one of my raw HM-TRP modules will only talk to either 3DR radio or another raw HM-TRP module!


I guess there is some difference in frequency between the "funny" modules and the rest ?

The "raw" HM-TRP module sits in my own PCB design, I have not tried to change the modules further.

I will get access to some measuring equipment shortly (spectrum analyzer etc), but do any of you have some hints ??


All modules etc are running the same (1.9) firmware, all modules are 433 MHz and all modules are using the same configuration etc.

Next is maybe to change the low/high frequencies with ATS commands and see if they can be shifted to work with each other ?



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    Check again if modules look the same. You can upload ANY bootloader to ANY module regardless physical frequency range which it is make for. But RF circuits are different and those HM-TRP's will work unreliable.

    • Thanks Marcin,

      if I look at my modules and the pictures from one of the authorized dealers:

      they look exactly the same (with the amount of detail I can see).

      The question is if the HK modules are using "bad" modules. They are enclosed in a shield so not too easy to see if the are equal to the other modules. I will see if I can open one of them and see whats inside...

  • There are counterfeit HM-TRP modules on the market. Maybe some of your are.

    Check if all of them look similiar and have same inductances next to SMA connector (AFAIK in 433 version they look like a made of copper wire winded on SMA element.

    • Thanks for reply Marcin!

      I got them from ebay (, guess its a good question if they are genuine or not! (or maybe the HK modules uses bad ones....)

      Are there any places to get the real modules without too much hazzle ?

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