EFHW antenna case and winder for Ham radio

thingiverse

Winder and case for endfed half wave antenna for portable radio operation like SOTA or POTA. QRP version (about max. 50 W SSB, 25 W CW) with FT-114-43 torroid and enough space for thin 20 m wire (40/20/15/10 m band version). Wire needs to be tuned with antenna analyser. Start at about 20.5 m and foldback / cut to lenght until lowest VSWR at 7.1 MHz reached. Installation of antenna as inverted-V or sloper. Other (non-3d printed) parts needed: 1 x FT-114-43 torrorid 1 x BNC jack 1 x 0.6 mm enamel / magnetic wire 1 x 100 pF high voltage capacitory (I used: HCZ101KBCDF0) 20 m of antenna wire (I used 0.22mm² - that's about AWG #24) 4 x Small screws to close lid (1.5 mm diameter) Printing: Print one body and one lid (choose one of the designs). 0.2 or 0.15mm layer height should work fine. 25 % infill is fine. PETG/ABS recommended (temperature resistance) Assembly: See pictures Winding the torroid: 2 bi-filar (twisted) primary windings and 8 + 8 secondary (1:64 transformer) For more on the winding and theory of end fed half wave antennas see here: https://www.nonstopsystems.com/radio/frank_radio_antenna_multiband_end-fed.htm