Slim Jim 450 Ohm J-Pole Antenna For 440Mhz

During covid-2020 I decided to go back and redo some antennas. Needing a new antenna for my apartment dwelling situation I decided to make a new slimjim Jpole. After sucess of the 144 Mhz version I tried a 440 Mhz version. Below is the design I used.

A = 49 cm
B = 0.7 cm gap at the 16 cm mark
C = 4 cm from bottom connect coax, adjust up or down to get best swr.

Both the very top and very bottom have both sides soldered together

The bandwidth will not cover the whole 440 Mhz band and it is smaller bandwidth than the 144 Mhz slim jim. But I got 1.5 : 1 swr on most of the upper part of the band.

If you use long piece of coax to your radio its best to use a choke balun just below the jpole to stop RF from coming back on your coax to your radio.