The 10m-4m-2m-70cm Antenna
Hi all,
my goal was an antenna, which works on 10m, 4m, and perhaps 2m and 70cm, and which works more or less in all directions.
To obtain a non-directional characteristic, I used a non-symmetric dipole. One side of the dipole has length 1.70m, the other has 3.30m length. The ends are attached, the coax cable hangs down, connected via a balun or a choke balun with coiled up coax cable, such that the dipole has a slight V-shape. To obtain a sufficiently wide-band balun I used about 10-20 windings of coax cable with about 30cm diameter.
It turns out that it works without a antenna tuner on 10m, 2m, and even 70cm, and with an antenna tuner on 4m. On 2m and 70cm I actually got quite nice results. I could reach relays as far as 100km away and even further, even though the relays have vertical polarization!
The simulation file for Xnec2c is for the antenna 4 m above a cylindrical building with 5m radius. It has hence 2 grounds, one for the building and one for further away. This is simulated with the 2 ground cards GN and GD in the xnec2c file. The pictures show the gain pattern when viewed onto the z axis and the y axis (where these axes appear as a point). It can be seen that the antenna radiates in every direction, and that it also has lobes which radiate very flat, important for DX'ing!
Vy 73, Gerald, DL5BBN
