Typically a commercially made PCB log with coax will have the coax shield soldered the full length of the PCB ground side feedline. You can also install an SMA connector on some and have the coax run parallel with the ground side of the PCB feedline. Lower frequency logs will have the coax running parallel with the grounded boom and insulated from it except at the connector.
I think its best to not solder it to the PCB and run it parallel to the ground side of the PCB feedline and also attach a number of ferrite beads on the coax at the feed point to help decouple the coax from the antenna. A log periodic is a balanced antenna and the right number and mix of ferrite beads will help decouple the coax from the antenna and force some balance.
Thank you for trying to solve my problem.
I have seen two methods on the internet to eliminate the excess currents that require using a balun.
1- The method you suggested: Feed the antenna from the end, i.e. the smaller dipoles, and do not solder the shield to the feeding path, and use ferrite beads or balun available on the market to create the balun, is that correct?
2- Using coaxial as a balun, which has been implemented in two ways in the articles.
And I wanted to know which method is correct:
1- Soldering the shield along the entire feed stripline path on one side of the board.
2 Passing the coax through the silicone insulation and soldering only the parts of the coax shield to the feed stripline that do not have silicone insulation.
And finally, in both cases, the coax inner is passed through the via and soldered to the other side of the board from the side of the higher frequency dipoles (smaller length).
Right?
