This is a repost of old antenna making video. The main advantage of this antenna is the null provided in direction perpendicular to the plane of the loop. You can use this to somewhat null out a local noise source or otherwise locally strong signal. Nothing is perfect.
The shield is the antenna; the potential produced at the gap. Maintain symmetry.
When building this antenna, it is critical that symmetry is maintained about a plane formed through the center of the shield gap and the feedpoint, with the feedpoint exactly opposite the shield gap. However, it is NOT critical the shield be shaped in a perfect circle; but as closely possible. Nor is it critical the flexible wire be centered inside the shield. Just make sure there are no kinks or curls in the wire when pulled through. And don’t let wires cross (the connector to spin) when tightening the SMA connector. Run the coax down and away in the plane of the loop to a preamp in a weatherproof box. Wrap all joints in weather proof.
This antenna will work fine from wavelengths 10 meters down to 160 meters, but the antenna size compared to the HF wavelengths is small so the signals (voltages) produced on the antenna will be small. It is necessary to use a low noise preamplifier to increase the signal before input to a receiver. Preferably this preamp is mounted at the antenna in a weatherproof box. The preamp can be powered from DC on the coax using bias tee’s. I am using a low noise preamp from SV1AFN, an ebay bias tee’s, and an LM317 voltage regulator board to adjust 20 Vdc down to 12 Vdc to power the preamp.
This antenna is made on the basis of PA0FRI/PA3GZK Wide Band Active Loop Receiving Antenna.
RBN
http://www.reversebeacon.net/main.php
Antenna Plans: http://pa0fri.home.xs4all.nl/Ant/Acti...
See also: https://pa0fri.home.xs4all.nl/Ant/Act...
Preamp: http://www.sv1afn.com/en/productcate...
HF Bias Tee’s get from ebay.
LM317 Voltage Regulator Boards get from ebay
Importance of the loop shield balance: https://www.w8ji.com/magnetic_receivi...
How the shielded loop works: https://owenduffy.net/antenna/shielde...
Small receiving loop antenna, magnetic loop antenna, magloop antenna, ham radio antenna, small loop antenna.
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