Here's a quick demo of my newly constructed 3.5" FSL. Reception is of the clear channel 50K watt station CFZM in Toronto under poor conditions.
FSL Antenna Demo with Tecsun PL-660

This FSL uses 140mm x 8mm rods from a different source since sufficient quantity weren't available from the eBay seller.

https://www.rf-microwave.com/en/ferrite-rods/171/

My experimentation showed that the recommended 27 full turns of the 1162/46 Litz wire were optimum for this unit.
My only other modifications were a plastic base to help secure the variable capacitor to the frame and use of a cut up plastic water bottle to form a stable shell for the loop windings.

The next test is to get out of the electrically noisy Washington DC area and try the FSL at a local mountain called Mt Weather. My immediate goal is to log US clear channel stations as far west as possible, such as KOA in Denver and perhaps even KFI in Los Angeles.

Again, a big thank you to Gary for the well documented plans.

Best,
Chuck Gafvert
Herndon, VA

<<<   Here's a quick demo of my newly constructed 3.5" FSL. Reception is of the clear channel 50K watt station CFZM in Toronto under poor conditions.
FSL Antenna Demo with Tecsun PL-660This FSL uses 140mm x 8mm rods from a different source since sufficient quantity weren't available from the eBay seller.

https://www.rf-microwave.com/en/ferrite-rods/171/   >>>

Awesome job, Chuck. You obviously aced the 3.5" FSL construction project, and I'm honored to have provided the plans!

By the way, that size of FSL antenna is ideal as a travelling DX companion, either on the road, or as a TSA-friendly overseas DXing antenna (once the Pandemic is over). Craig Barnes from Colorado has used a similar model to track down tons of TP-DX on ocean beaches here in Washington state, along with his PL-380.

There have been a couple of minor improvements made in that model since the construction plans were published, which I'll share with anyone interested (related to stopping unwanted ferrite sleeve rotation, and stopping the ferrite rods from sliding horizontally back and forth during travel).

Congratulations again on your success, and good luck tracking down lots of DX!

73, Gary DeBock (in Puyallup, WA, USA)

Paul,

The solution is a "rubber locking tab," which is precut on one side to fit around the curved PVC fitting, and cut flat on the other side to fit up against the rubber plumbing coupler. The rubber locking tab is then superglued to both of these surfaces, with the glue around the plumbing coupler allowed to contact the ends of a couple of ferrite rods. This glued-on rubber locking tab solves both problems.

I have attached a photo of a "rubber locking tab" on a new 6 inch FSL antenna, which is an all-new design incorporating all of the recent high-Q improvements with additional ferrite gain. These powerful new models provide sensitivity very close to the original 15" Monster FSL's-- without the $1K price.

Gary DeBock (in Puyallup, WA, USA)