ANTENTOP- 01- 2014 # 018

Simple Window Loop Antenna

Aleksandr Sterlikov, RA9SUS

The antenna was installed across wooden window frame. Perimeter of the loop in my case was 4.7- meter. Antenna could be tuned from 14 to 30- MHz. I fed the antenna 50- Ohm coaxial cable. However, also I used to 75- Ohm coaxial cable with success. Figure 1 shows the antenna. At antenna feeding terminal a simple home- brew symmetrical device (several turns coaxial cable coiled on to big ferrite ring) was installed.

Loop was made from wire in 0.3- mm (28- AWG) diameter. Wire was attached to the window frame by scotch. Variable capacitor should be with big gap between plates. However it is depends on power. I used usual capacitor 12- 495- pF from old tube receiver when I run 30- Wtts at 14- MHz and 10- Wtts at 21 and 28- MHz. My antenna was installed at 4th- floor at 5- store concrete building. Window was at North- East side. While a short time at 20- meter band there were made QSOs with 36- countries. There were ex-USSR, USA, Canada, Japan, Europe, Asia. I worked by CW (50%), SSB (40%), and then RTTY and SSTV.

RA9SUS

The window loop antenna may be installed practically at any window frame. Frequency range the loop antenna depends on perimeter of the loop. Small loop would be tuned to high bands loop with long perimeter would be work at lower bands.

Figure 1 Simple Window Loop Antenna

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