Re: Building a 3" Baby FSL

Gary DeBock

Hello Jim,

<<<   I am interested in building a 3" Baby FSL antenna and have a few questions.    >>>

Glad to help! The 3 Inch Baby FSL project is essentially a rework of the 3.5 Inch "Frequent Flyer" FSL antenna, for which a 22-page "Heathkit-like" full construction article is posted at

<<<   I just ordered 24 ferrite rods, but they are 8mm x 140mm, slightly longer than the ones Gary used. What impact, if any, will that have on the final product? Can I use a hack saw to shorten them? Is that even necessary?    >>>

No, it is not necessary! Using the 140mm x 8mm rods will give you a slightly longer and slightly more sensitive FSL than using the 120mm x 8mm rods (which are no longer available), but cutting the rods would give you nothing except a slightly shorter FSL.

<<<   What kind of material separates the rods from the PVC pipe and how thick is it? What kind of material separates the Litz wire from the rods? How is the Litz wire connected to the variable capacitor? (Any extra resistors or capacitors involved? Where on the variable capacitor do the wires connect?)   >>>

You can get a lot of information about the type of materials used by reviewing the full construction article linked above, but the 3" Baby FSL uses a slightly smaller rubber plumbing coupler (Fernco 1056-125 instead of Fernco 1056-150), some rubber locking tabs to prevent ferrite rod movement, and a much higher performance variable capacitor (384P model from Oren Elliott Products, or Mike's Electronic Parts).

Depending on the interest in (and demand for) the 3 Inch Baby FSL antenna another full construction article may be written for it alone, or possibly an addendum will be added to the article linked above. Although the larger and heavier 3.5 Inch "Frequent Flyer" FSL is slightly more sensitive than the 3 Inch Baby FSL, the smaller antenna puts up an extremely close fight because of its superior variable cap, which turns it into a compact DXing firecracker.

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


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