Surprisingly, it is MURS/LMRS, not LoRa. It’s true that LoRa has some other benefits over MURS/LMRS, namely bandwidth and coexistence, but when it comes to range, especially through ground clutter and hilly terrain, MURS/LMRS will outperform LoRa.
If you’re interested in the math:
Free Space Path Loss (FSPL) = 20Log((4pi D F)/C)
D = distance
F = Frequency
C = Speed of light in a vacuum
FSPL is a path loss without any absorption losses (walls, trees, hills, cars, etc.)—the range you get if both the receiver and transmitter were floating in deep space. More on this subject can be found here.
For a LoRa-based system with a gain budget of 157dB (Semtech SX1272), the freespace range is approximately 1,000 miles. Remember, you only get this in outer space, not on earth, so this is just for comparison, not an actual range calculation you will experience. It only shows the potential when compared to another system.
For a MURS/LRMS-based system with a gain budget of 162dB (TI CC115 + 2W transmitter), the freespace range is approximately 8,000 miles.
If we use a propagation model for the “real world” we get similar results. Using Weissberger’s modified exponential decay model (see: http://snip.ly/o65za ), this model accounts for absorption losses typically seen in real world environment.
LoRa = 0.5 Miles
MURS = 1.5 Miles
For our free Required Document Template click here. For our free ROM (Rough Order of Magnitude) – Project Estimator Spreadsheet click here.
Regards,
Steve Owens – CTO Finish Line PDS A Better Way for Small Companies to Develop Products
Steve.Owens@FinishLinePDS.com
Ph: 603 880 8484
94 River Rd | Hudson, NH | 03051 Click for Product Development White Papers
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