Yesterday I had the chance to visit fellow Puyallup resident and DXing pal Gary DeBock and experience his Ferrite Sleeve Loop antennas on medium wave and longwave. As you may know, a Ferrite Sleeve Loop is a relatively new approach that combines a large number of ferrite rods purchased for an equally large amount of US dollars. (Gary's pet acronym for the antenna is "Financial Sinkhole Loop").
The ferrite rods are arranged in a cylinder configuration along with a Litz wire coil and tuning capacitor. This strange looking antenna is guaranteed to raise more than eyebrows at an airport security checkpoint. The FSL antennas are downright sinister looking!
Gary has shown that the FSL antennas are as good or better than 4-foot air core loops. The advantages include lower noise than the air core loops and *much* smaller size. The much higher cost and effort to build a FSL is a big drawback though.
The results of the test were very impressive. On a whim I decided to pull out my mobile phone and take a video of the antenna's performance on distant 610 kHz KONA from Pasco, Washington, about 150 miles away. With the small Tecsun PL-380 some distance from the FSL, only background noise was heard. As the receiver approached the antenna, KONA came up from the noise and became clearly audible. In fact, an unidentified co-channel station was also heard in the background on 610.
A smaller FSL antenna that Gary built for longwave was even more impressive. NDB beacons totally inaudible on the PL-380 blasted in at very strong levels when the receiver approached the FSL antenna.
Gary is now en-route to the Oregon beaches with his FSL loops ostensibly for a family vacation...but I know better. It's actually a medium & long wave DXpedition trip in disguise. I'll be vacationing on the Oregon coast myself in a couple of weeks, and will have to convince my own family that the strange "FSL" contraption in the trunk helps the car get better gas mileage, or blocks highway patrol radar guns, or something like that...