Tiny Portable EFHW Antenna

The  proposed  solution  is  antenna winder  which  integrates  UNUN  in  the  center  and 
contains two compartments, in first one thin coax cable such as RG174/U of 
length 2.5m and ended with BNC connector is wound, while in the second one 
the thin wire of length 20.2m (some adjustment may be needed) is wound. 

Works fine for 40m, 20m and reasonably for 15m band. With wire link at 15.12m works also on 30m band.

You will need to print 3 parts, assembly UNUN (unbalanced-unbalanced transformer) and add 20.2m thin insulated wire. Detailed instructions in Tiny_Portable_EFHW_antenna.pdf or visit http://om2ju.com

OpenScad source file is provided too, feel free to experiment with modifications. If you decide to publish the results please leave the original header in the source file.