The information below is focused on obtaining your FCC license for operating UHF radios (403 - 473 MHz) when transmitting RTK corrections to GPS and GNSS receivers utilized in land surveying, construction, agriculture and mining applications within the United States. We've included some FAQs regarding the topic and a link to apply for your license through a trusted Frequency Coordinator.
Is an FCC license required for transmitting RTK corrections over UHF (450 MHz)?
YES – including all power levels. It’s a misconception that transmitting at lower power (under 2 watts) does not require a FCC license. Per the FCC, any transmission - at any power level in the UHF spectrum requires a license within the United States. That includes the low power internal radios integrated into receivers like the R8, R10, R12, SPS986...etc.
Is an FCC license required for GPS receivers that utilize a 900 MHz radio?
No. A license is not required within the US, Canada, Australia* and New Zealand*.
*In New Zealand and Australia Trimble 900 MHz radios are restricted to a portion of the 900 MHz spectrum by regulations in those countries. For this reason, Trimble 900 MHz radios are limited to a smaller frequency range and number of channels, but still offer the same performance.
Are 900 MHz radios license-free everywhere?
No. 900 MHz for GPS / RTK use is restricted from use in some countries, including: South Africa, Thailand, South Korea, and the UAE.
Why do you need a radio for GPS systems (RTK)?
If you need GPS accuracy, you need RTK technology. Real-Time Kinematic (RTK) is the technology used by GPS / GNSS receivers that enable real-time, centimeter-level accuracy. RTK corrections are transmitted from a base station to your GPS rover over the air by either radio, cellular, internet or satellite (RTX).
Without RTK corrections, your GPS receiver’s accuracy is 3-feet / 1-meter at best. That’s right, even the most advanced “survey-grade” GNSS receivers like the Trimble R12i, SPS986 and R980 can only provide 3-feet of accuracy when RTK corrections are not available.
Is 900 MHz better than 450 MHz?
The 900 MHz band is highly regarded for its reliability and effectiveness in ensuring uninterrupted communication - which can be crucial on projects where multiple 3D GPS machine control systems are operating and any downtime cuts into the bottom line. The downside of 900 MHz is that it's a low power radio which limits the distances corrections can travel - typically under 3 miles. Longer distances can be achieved with radio repeaters.
Land surveyors tend to choose UHF radios because they are capable of transmitting at high power which can travel longer distances - as far as 20 miles. UHF signals also perform better in hilly areas. The downside to UHF radios is interference which is common when working around hospitals, airports, hotels, military bases and other locations where 450 MHz radios are highly utilized.
Where to apply for an FCC license for RTK?
The FCC (Federal Communication Commission) is a department of the US government tasked with managing all radio communications within the United States.
The FCC uses Frequency Coordinators to assist customers with applying for an obtaining their FCC license. There are several Frequency Coordinators listed on the FCC’s website (link provided below).
Recommended Frequency Coordinator:
FOREST INDUSTRIES TELECOMMUNICATIONS (FIT)
FIT helped us and many of our customers obtain our FCC license quickly.
Link to: FCC application on FIT's website >>
How long will it take to get my FCC license for RTK?
It took roughly 45 days to process and receive our FCC license.
What is the cost to obtain your FCC license for GPS / RTK:
At the time of writing this article, we paid $475.00 to obtain our FCC license which included two channels / frequencies.
I have my FCC license - Now what?
Once you have your FCC license we can program your assigned frequencies into your radios and GPS receivers. Depending on your application you will typically receive 2 frequencies specific to you and your location. Additional frequencies can be requested at the time of your application.
Programming transmit frequencies requires special software that only authorized Trimble resellers have access to. Your frequencies are assigned to the serial number of your radio or GPS receiver and can be emailed to you in what's called a ".set" file. You can then install the .set file into your GPS receiver or radio with either WinFlash (older receivers) or Trimble Installation Manager (newer receivers).
With your own assigned frequencies, you shouldn't have any trouble getting mixed signals from other surveyors in your area. However, it's good practice to use the "listen" feature built into your radio before transmitting. If someone is transmitting on your assigned frequency, you should select another frequency to transmit on.
Helpful Links:
- Trimble – What is RTK
- Trimble Support Bulletin: FCC Narrowbanding Requirement for UHF radio (2013)
- FCC license information for UHF radios (FCC website) >>
- Trimble - What is RTX