Quick and dirty 868MHz antenna in 5 minutes

This is simple antenna for 868MHz built in 5…10 minutes. Take about 10cm of RG214, a plate of PCB with the copper at one (or both) sides. Remove the coax shield and inner dielectric on one side in length of about 85mm. You will cut this to proper length during SWR measurements.

Simple antenna made with piece of coax and piece of old PCB.

Drill the 9mm hole in the PCB and put the coax through. Solder the coax shield to the copper:

Coax shiled soldered to copper PCB and RG214 behind (I had double shielded RG214 from Amphenol)

On the lower side, solder the feeding coax:

Feeding coax soldered directly to the antenna dipole

Now connect the SWR or VNA or any other antenna tester and check the central frequency. It should be around 820-840MHz. Cut about mm at a time and check the antenna with your instrument. I ended with 79mm of the dipole length for central frequency 868MHz:

Dipole starting length is about 85mm

Finally, add some hot glue to fix the position of the cables and the dipole:

Use some hot glue to fix the dipole

Here is the final measurement result:

Final measurement: SWR = 1:1.125 – not bad for 5 minutes antenna

 

Live test with LoRa gateway and my end device

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