Device:
Handmade prototype * 2
Frequency:
923.875 MHz
Modem Settings:
Long_Fast
Max distance:
395m
Note:
This is an initial trial; the device is assembled using the breadboard and wires.
Device:
TWC_Mesh_V3 * 2
Frequency:
923.875 MHz
Modem Settings:
Long_Fast
Max distance:
464m
Note:
The first version of our design prototype has several design flaws and lacks refinements in all areas.
Device:
TWC_Mesh_V4 * 2
Frequency:
923.875 MHz
Modem Settings:
Long_Fast
Max distance:
1.7 km (stop due to no roads ahead)
Note:
In TWC_mesh_V4, we corrected the flawed PCB design, selected the suitable antenna, and reviewed the battery selection.
Device:
TWC_Mesh_V4 * 2
Frequency:
923.875 MHz
Modem Settings:
Long_Fast
Max distance:
4.49km
Note:
LoRa technology can be affected by interference caused by buildings and natural surroundings, leading to limitations in signal penetration. These obstacles can reduce the effectiveness of communication in regions characterized by complex architectural layouts and mountainous landscapes.
Throughout our investigation, it became evident that the antenna plays a significant role in communication.
Paying a higher price for antennas does not always mean that the quality is superior, as their effectiveness can appear somewhat mysterious at times. It is recommended to:
- Exercise caution with antennas that assert to provide increased coverage.
- Avoid products that do not provide comprehensive specifications.
- Examine the vendor's other products, as their understanding of the items they sell may be insufficient on occasion.
Designing our own antenna allows for a high level of customization, but it can become challenging when multiple devices need to be built.
Ensuring that your antenna is properly tuned to the operational frequency is a critical step. Many low-cost antennas are often misaligned to an inaccurate frequency, resulting in a significant reduction in signal strength. Using a vector network analyzer (VNA) can validate that the antenna is correctly calibrated with the transmission circuit, ensuring that it operates at the correct frequency.
Having the testing performed by a professional laboratory is always a good idea.
At present, ANT-916-CW-HWR-SMA performs optimally with our device; please refer to the other antenna report provided here.
Hackaday's Introduction to Antenna Basics (link)
An excellent series of presentations on the basics of antenna design and functionality, presented by spacecraft radio engineer Karen Rucker.
HeyWhat'sThat
Free with path profiling options
Radio Mobile Online
Radio Mobile Online is a radio wave propagation prediction tool dedicated to amateur radio
Times Microwave Systems
Coaxial Cable Attenuation & Power Handling Calculator
Solwise Link Budget Calculator
Predict the received signal strength
Amateur Radio Toolkit
Android app with lots of antenna information
1/4 Wave Ground Plane Antenna Calculator
Quadrifilar helicoidal antenna calculator
Building an 868/915 MHz co-linear antenna tutorial
868 MHz antenna schematic PDF
915 MHz antenna schematic PDF