But the loopstick is only one of a class of electrically-small antennas (small compared to the wavelength in free space). Electrically-small antenna theory has been fairly stable since the 1960's, though there has been some minor refinements.
“But the loopstick is only one of a class of electrically-small antennas (small compared to the wavelength in free space). Electrically-small antenna theory has been fairly stable since the 1960’s, though there has been some minor refinements. “
Electrically small antennas have poor gain figures. For the purposes of many ferrite loop/stick antenna applications this is “good enough” - plus you can get a little directivity to null out interference to make up for sub-optimal gain.
The trick here, if I’m reading between the lines correctly, is that you’re getting an electrically resonant antenna in a small dimensional footprint but avoiding the penalty of very low gain.
Looking forward to more on this topic.
>> Ferrite-core loopsticks are good for only low-frequency signals <<
If you’re referring to the loopsticks’ current sizes, I get it.
But what if they could be scaled down in proportion to wavelength?
For example, let’s say a current loopstick optimized for 300 meters (middle of the MW broadcast band) is three inches long. So what about a loopstick for the three cm band — which (if my calculations are correct) would be 3/10000th of an inch long?
(And I guess the “wires” wrapped around the ferrite core would be smaller by maybe a factor of ten to the minus three.)
Clearly, the manufacturing process for something that tiny is hard to imagine.
On the other hand, maybe it will eventuate some day, because nano-technology has already accomplished so many other tricks that defy the imagination.