The LoRa Developer Forum is now in read-only mode and new content will not be added.
Semtech, in its commitment to enhance user experience and streamline content, has successfully integrated the LoRa Developer Portal content into Semtech.com. As a result of this consolidation effort, the LoRa® Developer Portal Forum will be discontinued on May 1st. After this date, you will be automatically redirected to Semtech.com.
For any technical support related to LoRa, please feel free to reach out to our experts here. If you have sales inquiries, please contact us here.

FORUM

Why VSWR value changing?

LoRaWAN® implementation Radio & Antennas
#1

Hi everyone, last night i was testing my 145MHz Yagi antenna for VSWR value. I realized something stupid. When I was keeping the antenna close to ground, VSWR value was changing. Also, I stanted in front of the antenna same thing was happen. I search about that on internet but i am not be satisfied. If any one know the factors about this, please tell me. I will be really appriciated. Thanks a lot.

#2

That nearby objects affect antenna tuning (and hence VSWR) is to be expected.

How much the tuning is affected depends on the objects and the distances involved.

1 Like
#3

When the antenna touch or be near to the ground, there will be a parasitic capacitance in between. Thus the impedance of the antenna changed, so will be the VSWR reading.