from FB group Building Transistor Radios 2018-11-19
I shared my loop antenna – see photo, and it is somewhat 2 dimensional. The arms are 762mm across but the depth of the windings is only about 35 mm. Compare that to the ferrite loopstick at the other extreme, it’s 10 mm diameter but 100 mm long. I’ve noticed that the loopsticks are quite directional, I can null out a strong station effectively.
I was thinking that if I wound another loop antenna using a square cardboard box, I could cut the box down so the windings have little depth, only 50 mm or 2 inches. This gives a wide ‘figure eight’ pattern with minimal directionality. But should I wind the coil over a deeper box, about the same depth as the width or length? This would give a narrower figure eight pattern with more directionality.
This would take more wire, because spreading the windings over a wider area gives less inductance so more turns will be needed to get the same inductance. Would it be worth doing this to get a narrower pattern? The loop antenna would be bulkier, taking up more room.
