The Nano Edition series is a compact Lora device with high efficiency internal compact Lora PCB Antenna, ultra-low noise figure amplifier and internal GPS module. This series aims to balance the RF performance, size, rugged construction and power consumption.
For the firmware, Meshtastic firmware can be ported to this design with minor modification. More details are illustrated in the Firmware Section of this document. Meshtastic can send off-grid message using inexpensive hardware to create your personal mesh.
The coverage of this credit card size Lora device was tested in the urban area which full of more than 150m skyscraper towers. In the experiment (TX:20dBm, Freq:915Mhz, Medium/Slow), 773m communication distance had been tested, no timeout or re-transmitting occurred. According to the link budget, this system could reach far further than 773m. More details are illustrated in the Real World Testing Section of this document.
Typical RF Performance
|Lora Max RF Output Power||20 dBm|
|Lora External RX Ultra-Low Noise Amplifier (LNA)||Gain = 15.64 dB, Noise Figure = 0.8dB|
|VSWR of Lora PCB Antenna (US Edition)||< =1.5 @ 915 MHz|
|Impedance Bandwidth of Lora PCB Antenna (US Edition)||882 MHz to 935 MHz for VSWR < = 2|
|Positioning And Navigation Module||Build-in GPS Module, LNA and patch ceramic antenna. GPS, BDS and GLONASS are supported|
|Schematics for Nano Edition G1||meshtastic_mesh_device_nano_edition_17_mar_2022.pdf||Version: 21 Jan 2022|
PCB (Nano Edition G1)
|3||Semtech SX1276 Lora Transceiver|
|4||USB Type C Socket|
|5||CH9102F USB to UART Bridge|
|6||Ultra-Low Noise Amplifier (LNA)|
|7||RF Switch (RF Performance Measurement)|
|8||915Mhz Lora PCB Antenna|
|9||ATGM336H-5N-71 Whole Constellation Positioning and Navigation Module|
|10||GPS Ceramic Patch Antenna|
|12||1.3 Inch OLED Screen|
The Plastic case has not been chosen due to relative high initial cost on Plastic Injection Mold. Plastic case usually require a large volume of sales to dilute the mold cost.
Metal cases have relative low initial cost but not easy to deal with the internal antenna.
RF Design - Lora (Nano Edition G1)
TX Circuit and Antenna
For conduction test, an IPEX connector needs to be soldered on P1, 0 Ohm 0402 resistor R8 also needs to be moved to the place of R9.
For Instrument Setup, RF Explorer 6G Combo PLUS Spectrum Analyzer and 30 dB Attenuator was used to measure the RF transismission power.
Summary for Conduction Test
|TX Setting||Measured Output Power|
|14 dBm||15.5 dBm|
|20 dBm||19.5 dBm|
For Antenna Measurement, an IPEX connector needs to be soldered on P1, additional one 0 Ohm 0402 resistor also needs to be soldered on the place of R9. C15 need to be removed.
For Instrument Setup, low cost Nano VNA is already sufficient for this measurement. All metal around the antenna will have a notable effect on the antenna performance, so the DUT should be suspended in the air during the measurement. During the test, the antenna must be installed inside the product, as close as possible to the final use state, because...Read more »