Water Tuned Sliding Capacitor Loop


On this loop I decide to associate some successful techniques:

1)The printed circuit sliding capacitor
2)The water remote tuning system
3)The alligator clip ad on capacitor
The loop is made on 2.50 CMS coaxial cable and it can cover from 14 to 30 MHz

There are two ceramic capacitors on the back of the sliding capacitor calculated to cover 40 and 80 meters.


One of each capacitor legs is soldered on one extreme of the loop and the other capacitor leg to a short piece of coaxial braid and then to an alligator clip.

To calculate the capacitor value I went to REG Edwards’s formulas page that can be find on the “Magnetic Loop Links”.

It is possible to calculate other capacitors to cover 30 Meters and 60 Meters.

The hand adjusting injection serynger have a calibrated scale that informs the operating band helping fast frequency visual information.

This antenna is very light and the weight is about 800 grams and it is easy to carry and adjust on a walk and talk pedestrian QRP operation.

This antenna was designed for low power use due the low proximity between the capacitor plates


The coaxial cable and the plastic tube are carefully glued with Super Bond.

On the upper left photo shows the coaxial cable and connector reinforced by thermal shrinking spaghetti, a technique that must be used on all RF cable and connector joints that will give additional protection on the pedestrian operation cable stress.

PY1 AHD ALEX (Alexandre Grimberg).