| Z-dipole for 160 meter If your space is not big enough for a full size half wave 160m
dipole this Z-dipole might be a good choice for you. Z-dipole is almost
as good as a full size dipole, the gain is only abt 3dB less (half
S-unit). You can install it at a height from 10m to 20m
or even lower. It is not the best DX antenna but it is very useful for local 160m QSOs. The construction
is not critical, you can adapt the shape according to your space.
Z-dipole top view. The nominal total wire length is abt 84.6m with a pure copper wire. The green ones are ropes. The length is a bit shorter with an insulated wire and the length is also depending on the height and the ground properties. Allow some fine tuning by starting with a 1-2 meter longer wire and fine tune it to the best SWR by folding back the wire ends. 
3D radiation pattern is good for NVIS QSOs The feeding point impedance is somewhat lower than 50 ohms depending on the height of the antenna. Thus the SWR is reasonable without an antenna tuner. And don't forget a common mode balun in the feeding point! See more here |