Can i switch between 433/868/915
Contents
Introduce
In some case, user orders some LoRa products but they want to chanage to other frequency use. Here instroduce the possibility for Dragino devices.
If you don't know which frequency band you use in your country, you can refer this URL:
- LoRaWAN Country Frequency Band List.https://lora-alliance.org/sites/default/files/2018-04/lorawantm_regional_parameters_v1.1rb_-_final.pdf
Hardware Aspect
Dragino LoRaWAN products mainly use different chipset solutions.
Base on SX127x
In this hardware design, there are two radio paths in hardware: high frequency and low frequency. The 868Mhz and 915Mhz hardware use the high frequency path and 433Mhz hardware use low frequency path.
If user has high frequency hardware then he can use the frequency between 860 ~ 960Mhz. But he can't use 433Mhz frequency, since in this hardware version there is no radio path for 433Mhz. If use has to use 433Mhz, the distance will be very short (less than 1 meter). In the high frequency, there are two version of hardware: 868 and 915, the difference is minor, difference are best tuned in which frequency point (868 or 915).
If user has low frequency hardware then he can use the frequency between around 433Mhz. But he can't use for 868/915 Mhz frequency, since in this hardware version there is no radio path for the higher frequency. If use has to use 868/915Mhz, the distance will be very short (less than 1 meter)
Base on SX1262
Base on SX1301, SX1308, SX1302
The are gateway chip solutions.
These solutions have a Band Pass Filter in the Radio path. The bandwidth for them are:
- 868 version: 863Mhz ~ 870Mhz
- 915 version: 902Mhz ~ 928Mhz
If you have a 868 version , you can only used in the support bandwidth because all other frequency will have a big Attenuation in the signal. In such case,if the end node very close to the sensor, it might work, but signal will be very poor.
