Shortened 2 elems foxhunting antenna
Introduction to the "Shorty for Two" 2 elements Yagi utilizing beta-coils
and extremely shortened elements (about 65% of the full size dipole dimensions).
Blueprint of the antenna. The coils used need to be adjusted to get the required
SWR and F/B ratio.
As a guidline the following procedure can be followed:
1) assemble the driver first (including the balun if needed) according to the specs and mount on the boom; 2) connect a 50 Ohms RF source tuned to the target frequency (mid 2m band) to the balun; 3) adjust the driver to SWR 1:1 by first squeezing the coil or shorting windings on the outer edges of the coil; 4) the coil can be replaced by a new coil adjust for shorted windings etc.; 5) do not initially clip the elements, keep them according to the specs; 6) after SWR 1:1 is obtained, install the reflector element to the boom; 7) use a small RF source at some distance 10m and tune the variable coil to get the maximum dip on the back of the antenna. 8) is should not be necessary to re-adjust the reflector coil during the foxhunt.
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Last update: 08-04-2006