A few words about lora, different models of lora have different characteristics. Although some modules specify the range, they may filter out the surrounding frequencies. For example, if an antenna has a nominal 868M frequency, then it is within the range of 868 ± The performance within 10M may be very good, while the surrounding effect is relatively poor. Screenshot below.

Measurement Principle

        How to measure can wait first, you need to know what to measure and what the standard is. For this, we generally focus on two standing wave ratios and Smith charts. We will not explain these two in detail here. If you want to know more about them, you can look at the links you found for reference.

        Standing wave ratio: According to my own understanding, briefly explain the following standing wave ratio, how to explain whether an antenna is good or not, we want all the waves from the antenna to be scattered, then the closer the value is to 1, it means how much is scattered and how much is scattered. effect is better. But the actual situation may not reach 1, so to see if an antenna is good or not, it is enough to see if it is close to 1 within the nominal value.

        Smith chart: After talking about the standing wave ratio, let’s talk about the Smith chart. About it, you only need to know that the closer it is to the center of the circle, the better. It has a ring with an impedance of 50 ohms, and on the top of the circle is the inductive , the lower capacitive resistance.

Measuring Tools

        If you want to do a good job, you must first sharpen your tools. If you want to measure the antenna, tools are indispensable. Three in total.

        1) Vector network analyzer: It is more intuitive to use this. There are VSWR options and Smith chart on the top. You can see the picture below. The model is AV36580A, and the range is 300kHz-3GHz.

        2) Antenna interface toolbox: It is used together with the vector network analyzer to connect the analyzer and the antenna. The model is AV31121A.

        3) Antenna to be measured: an antenna, you can know it by measuring it. Here, in order to illustrate the quality of the antenna and the reasons for the space, a good 868mhz Helium miner antenna is compared with a bad 868mhz Helium miner antenna.

Measurement Process

        Step 1: The measurement process is relatively simple. In the toolbox, select the antenna interface that matches the antenna, and connect it to the analyzer after assembly.

        Step 2: After turning on the analyzer, you must first specify the starting and ending ranges. For example, I choose to measure an 868Mhz antenna, then I can set the range from 860MHz to 870Mhz. Setting this range is convenient for observation.

        Step 3: Check the effect and compare the antenna differences.

Analyze Data

        Look directly at the frequency waveform here. The following is a comparison of the good 868Mhz frequency waveform and the bad 868MHz frequency.

        1) Good 868 frequency waveform, standing wave ratio diagram and Smith chart. It can be seen from the standing wave ratio diagram that it is basically in the range of 868, and the Smith chart is also relatively close to the center, indicating that it is a better antenna.

        2) Bad 868 frequency waveform, VSWR chart and Smith chart. It can be seen from the standing wave ratio diagram that it is basically not in the range of 868, and the Smith chart is also far from the center, indicating that it is a relatively bad antenna.

        Choosing the high-quality Lora Helium hotspot miner 868mhz antenna from Guangdong Amplitec Tech Development Co.,Ltd can greatly improve the efficiency of mining HNT.