Helium LoRa hotspot modeling

Helium LoRa gateways are popping up like mushrooms all over the world. Due to variations in siting some users (on hills/tower blocks) are experiencing +50km with a basic antenna whilst others (below hills/tower blocks) are struggling to communicate 5km with the same hardware. Using LoRa technology, the signal is able to propagate many miles even in a city on low power but is still attenuated by obstacles, especially buildings.

The location, and height especially, is everything to getting the maximum range.

WARNING: Do not fit a high gain antenna unless you reduce your transmit power accordingly or your effective radiated power may exceed authorised limits for the ISM band. Use the CloudRF EIRP calculator in the feeder menu to ensure you are legal. The ISM band in the US and EU is monitored for abuse by spectrum regulators.

EIRP = Effective Isotropic Radiated Power AKA “Power out of the antenna”.

Eg. 27dBm + 6dBi antenna = 33dBm EIRP. Legal in US (36dBm), Illegal in EU (20dBm)

Interface settings will vary by hardware and region. Basic settings for the US and EU are listed in the table below.

Value	US / FCC	EU / ETSI
Frequency	915MHz	868MHz
RF power	0.5W / 27dBm	0.025W / 14dBm
Antenna gain	2.3dBi	2.8dBi
Legal EIRP limit	+36dBm (FCC part 15) https://afar.net/tutorials/fcc-rules/	+20dBm (ETSI SRD) https://support.sigfox.com/docs/radio-constraints-for-international-certification
Antenna type	OEM half-wave dipole	OEM half-wave-dipole
Receiver (Rx) gain	2.15dBi	2.15dBi
Sensitivity	-120dBm (City), -130dBm (Rural)	-120dBm (City), -130dBm (Rural)
Bandwidth	0.125MHz	0.125MHz
Feeder loss	0dB	0dB
Model	ITM	ITM
Reliability	60%	60%
Context	Average	Average
Diffraction	Off (included)	Off (included)
Clutter	Soft	Soft
Clutter attenuation	0.01dB/m	0.01dB/m
Resolution	16m / 52ft	16m / 52ft
Clutter	Soft	Soft
Colour schema	LORA.dBm	LORA.dBm
Radius	10km / 6Mi	10km / 6Mi