High-Q LW loop for the PL-380


slowfly55
 

Though fascinated by the ferrite stick transplants of Gary I have still scruples to alter the outer appearance of my URLs and prefer the passive loop approach.
On Henry's homepage http://homepage.ntlworld.com/henry01 I fell on an small and simple loop antenna that is more than a gadget.
Following his plan and calculations I constructed such a loop of
12" x 9" for LW. For a better Q I built it with foamboard 5mm instead of corrugated cardboard and invested a roll of 60x005 litz wire for 55 turns instead of copper wire.Now having sacrificed so much litz an
air variable tuning cap was mandatory.The result is a relatively small and easy transportable LW antenna. If you are interested I can put a self declaring photo in the photo section.
The performance boost of this "gadget" was far beyond my expectations.
The tuning of the loop is extremly sensitive (small bandwith), so that the reduction drive of the cap is helpful. Average s/n gain is 15-20 db on the PL 380.Here are some day measurements:

Barefoot with loop
162 kHz France Inter 15 01 barely audible 29 25
177 Deutschlandrad. 15 02 not aud. 20 18
207 Deutschlandfunk 15 13 38 25
234 RTL 15 00 barely aud. 28 25
270 Czechsk.Prag 15 00 not aud. 15 18

This PL-380 loop combination is now equal in performance to my
best LW receiver: no, it is not the Sony ICF-2010 it is the sowiet
Selena B212.

Peter K. in Schaffhausen/Switzerland

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