3 Dec 19 changed from HF Dipole to homemade quadrifilar helix antenna. Wood, 12 gauge copper wire with insulation on and hot glue. Many tries, even having a NanoVNA; tuned for 146 Mhz; symmetrical lengths; 0.41 w/h ratio; quarter wave RHCP insert. Antenna, RTL-SDR, Pi4. Improved with obs 1315448 after adding 3 loops in ferrite core choke and turning left 90 deg; slightly lowered freq. Now better at times than my other ground plane. On table next to house under large cottonwood (no leaves).