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The coupling by a FT37-43 with 7 turns 
The small loop in action on 80m. by switching a 1200pF capacitor over the tuning capacitor
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This is a updated collection of easy projects for radioamateurs and swl's. See all of my projects at OLDER POSTS down on this blog. Enjoy,73 John
Tuesday, February 04, 2014
Mini Travelloop for receivers
Portable shortwave receivers are normally equiped with short telescopic whip antennas producing a poor reception. This option has more selectivity and a better impedance (low Z) over the 6.8-31 MHz range.
The design uses a single 15-520 pF type tuning capacitor combined with a FT37-43 toroid having 7 turns on the coax side. The loop is made of 3mm brass wire 1m long. Use only plastic enclosures. Tuning range is 6.8 - 31 MHz with oustanding performance. This is also a verry good direction finding antenna. A RG-213 loop of 130 cm gives a higher Q with much stronger signals.
