High Efficiency Single Knob Tuned Half Wave TX/RX Loop Antenna. Developed in the Netherlands.
Last update TX version 13.4.23
This Site is Now Operationnel by >>> www.holland-shortwave.com <<<
RX Loop PCB with parts
Professional double sided RX Loop PCB can be ordered as described on
PCB Price is 12,50 Euro including Power Board and White core.... Price is Exclusive Shipping costs. Payment by Bank or PayPal+ 3,00 Euro Commission.
Below the latest (second) TX Double sided PCB 100 x 150 mm. All Green tracks Top and Bottom the same and metalized by holes as well, to make this PCB universal as possible.
Below an example of a PVC box with a tuning capacitor and PCB concept for the Half Wave Loop.
We calculate all sizes in the the Metric system only. I have deeply respect for people on the other side of the Ocean, who can calculate every day by Inches and Fractions.
We started two years ago with a Push Pull RX Loop Design.
Together with PA0FRI and myself, PD0EEA.
For this I designed a PCB that has been sold worldwide more than 100 times, from Canada until New Zealand, and works to full satisfaction from 0.1 to 30+ MHz.
This RX board has been revised three times for optimal results in the last two years.
Our totally new TX Loop design.
As the demand for a universal TX loop (120 cm) became more apparent, I came up with a new previously unpublished design.
"Closed Half Wave Variable Tuned Loop"..
Without boring calculations that almost always deviate from reality.
A closed loop design, all in one box with mono knob tuning, with a minimum bandwidth of 120 KHz. and a overall SWR of up to 1:1.2 maximum from 3.5 to 15 MHz. (80, 60, 40, 30 and 20 meters).
TX / RX HF Loop for in and outdoor use.
Completely different from the "Google" copies with awkward tuning C in the top, and with a 50 Ohm inside coupling loop. A system that is also very narrow-band and difficult to realize on a roof or at a distance in a garden.
A clumsy system that has to be constantly re-tuned due to the narrow bandwidth.
The double-sided PCB and is 100 x 150 mm in size. This PCB is offered complete with 3 transformers and a common mode choke. there are also four relays for the 80 meter band and correct SWR on other bands. The necessary tuning capacitor of 100/150 PF and the box are not included. The power is around 100/150 watts continuous. By this Mono knob tuning concept, it is possible to operate this PCB remotely with a single motor and a 5-core cable for the relay control. All this can be filled in as desired.
This PCB is designed as universally as possible and equipped with wide tracks and large metalized pads with 3 mm bores for possible modifications and adjustments.
To give you an idea of how it works, I'm publishing screenshots of the spectrum analyzer regarding the SWR on all bands ad the end of this page.
Due to a specially wound transformer, the Loop is adjusted from 80 to 20 Meters, with an optimal SWR
Resulting in an efficiency of 85 - 95% on all bands with excellent bandwidth. from 130 up to 230 KHz.
The reception results on all bands are optimal with a Tuned half wave system. Even without RX PreAmp. On all tuned frequencies you will have the same Gain.
The basic principle of this Tuned Half Wave and the bandwidth
The phase shift between voltage and current in an inductor.
A sinusoidal voltage has a maximum rate of change at the zero crossing and a zero rate of change at the peaks. You know from Faraday's law that the amount of voltage induced across an inductor is directly proportional to the rate at which the current is changing. Therefore, the coil voltage is maximum at the zero crossings of the current where the rate of change of the current is greatest. Also the amount of voltage at the amplitude of the current is zero. This phase relationship is illustrated in Figure 9-29. The figure clearly shows that in a coil the voltage is 90° ahead of the current.
Measurements of the Half Wave Closed loop, from 3.5 to 15 MHz.
Analyser Calibrated at 50 Ohm By the latest BLUE VNA PRO 2 (Perfect Precisely Device !!)
80 Meter SWR + Bandwidth +/- 110 KHz... With a totally perfect symmetrical passage
40 Meter, Bandwidth +/- 150 KHz.
20 Meter, Bandwidth +/- 320 KHz.