HM-TRP radio link issue

I just setup my XXL like base and XL like rover. (NEO-M8P)
To send RTCM correction from base to rover I bought HM-TRP radio telemetri kit

using its default setup I experience on rover side about 50 % of the received RTCM messages fails with CRC error. Like the consequence of this correction age stays around 30 - 50 sec which probably too long and rover never goes to RTK fix.

Would somebody help me to get an usable configuration of LoRa HM-TRP ?
The current configuration is

code rate= 4/5
payload data length=32 bytes (I have tried 64 byte too with same result)
Wireless (?) = 1098.10 pbs

Any help would be highly appreciate


I’d like to add: of course I have tried and substituted the radio with simple wire…it works fine :wink: no crc error and correction age is always 1 sec as it should be.

Have you tried this configuration software?

I have not tried yet, but I’ll do.
One of my problem is I cannot find USB-UART driver for it for WIN10.
Currently I just can access the radio to connecting to it via an FTDI adapter.
Do you know a link for USB-UART driver to access it via directly to USB? (WIN10)


I don’t recall having to install any drivers on my Win10. With SikRadio software it was just plug and play. Here are the driver details I have for the radio module.


Thank you. I have same FTDI driver installed just 2.12 version.
Unfortunately when I plug in the radio nothing happen, no new virtual port, nothing…
I also tried to install Silicon Labs’ driver but no luck with that too…

After several hours of figthting with different drivers I have looked onto the module itself. Then I was really surprised! On the module where the FTDI chip would need to be, there is NOTHING only the place of the chip. So seems to be the FTDI chip is simple not soldered!
(Hey Drotek! Quality control? Quality assurance?!)

Now I am going to open a ticket at Drotek.

Drotek was fair. No questions, no excuse, simple they sent new radios (it is on its way still, hope both boards will be in the packet)

For information whom is concerned in:

to send/receive RTCM correction LoRa mode is not good since it is using max 127 byte packets. RTCM messages bigger than that, therefore messages cannot be transfered well in this mode, you will get a lotof CRC error…
To send/receive RTCM messages set the radio into FSK mode. In this mode it is working perfectly.


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