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. A FT37-61( 4c65) with 3 turns can also be used. 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 gives a higher Q with much stronger signals.

The coupling by a FT37-43 with 7 turns

The small loop in action on 80m. by switching a 1500pF capacitor over the tuning capacitor

Disclaimer:I'm not responsable for any damage due to improper reproduction of my projects.