A simple coupler to 27 MHz
Since I had problems with the antenna tuning and therefore the stationary relationship was excessive, I have designed a coupler to 27 MHz that works like a charm. It is a very simple and readily available components assembly. Such is the degree of adjustment that have come to doubt the stationary meter as reflected wave in the needle of the instrument or move. Measured by a dummy load insertion, losses are negligible.
I hope you like it as much as me.
For the realization of this coupler I used two variable capacitors commonly used in radio recorders. These have the advantage of incorporating four sections (two AM and two FM) and its partners trimers allowing us a great number of combinations and a variety of settings. For mounting at hand I used the two sections of parallel FM (20-60 pF in total) and thus I managed to adjust a vertical antenna 5/8 with an initial ROE of 1: 2.5 to 1: 1.1. Despite having a dielectric of these capacitors they are holding polyester smoothly exceeding 120 W peak power SSB.
Depending on the type of antenna and equipment, using switches S1 and S2 can be enabled or not capacitors, as low or high band of 27 MHz is used.