TECHIES' CORNER:Tweaking and Tuning Amplifier Circuits; Building a Low-Pass Filter, etc.!
The following design for a three element yagi directional antenna is
frequency-specific to 98.5 MHz. Stay tuned for a more thorough treatment
of yagi antenna design.
We have found these antennas to be very effective if you can deploy them out in the open. They seem to interact unfavorably with trees, however, so may not be the best choice for stealth installations. Remember that this array will produce a pronounced directional pattern with a fat lobe of the front, a small lobe off the back and deep nulls off the sides. The ideal application for this array would be an operation from a hilltop overlooking your town where most of the population will be pretty much in one direction. We operate at 98.5 so the dimensions given will land you just below there for final trimming. If you operate low in the band the elements will want to be longer.
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