Using a different base

What is the process to enable reception of rtcm correction from another base. Most bases Leica Trimble topcon etc transmit over 450mhz. These corrections are often made available for all contractors on some civil engineering projects.

Is there a radio modem available that needs to added to the rover to receive this data ?

All professional receivers come in options of Low-Band UHF (450MHz) and High-Band UHF (915MHz). Most contractors that I have come across use 915, but many contractors that are in dense and adverse conditions use 450. 915 is faster and has longer range, but 450 penetrates better.

The Emlid products are 915MHz.


What about licensing? Wherever 900MHz is legal, it seems to be an unlicensed band. Is the same true for 450MHz?

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The “process” is that you buy a compatible radio, (e.g. PacCrest, Satel etc) that is running a compatible radio protocol (e.g. SATEL 3AS, PCC 4-FSK, PCC GMSK, TrimTalk) and tune your radio to your base. You then use a serial cable connection from your radio to your Emlid receiver and feed it RTCM3 correction stream. Job done.


Hi Alan,

By the way, we have a post about testing Reach RS+ with external radios:

You can use external radios for integrating Reach with 3rd-party base.


Thanks for your responses.

I was wondering with it had the opption to install a 450Mhz radio on the unit. I assume the answer is no.

I am in Australia and I haven’t heard of anybody using 900Mhz (mainstream). Invariable the 450mHz is used on civel/mining/machne control etc. also believe <900mHz may be banned as I remember some US modems on that frequency cant be used here.

Nevertheless the fix is to get a 900Mhz radio or even rig up a repeater that can do the frequency swap over.


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