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Hi, all concerned:
The W8JK antenna can keep its same general broadside pattern when the lengths and spacing vary widely. So, you can build one to fit the space available, and you need to pay attention only to keeping the 4 lengths of element-wire close to the same length, and to crossing the phasing line over between element feedpoints**. It will work well over a 3-to-1 frequency range. Element maximum-currents and voltages can be quite high, so use the largest practicable wire size, and good insulators. Exact lengths or "resonance" do not seem to affect patterns. It is probably easier to use open-wire feedline. To make the antenna easier to tune, you can vary the feedline length between the transmitter and the antenna. Make your feedline "tune the antenna". Modeling it with EZNEC shows that, at lower frequencies, it can have more radiation at lower angles than some other simple antennas at the same height above ground, and that shifting the feedpoint away from the center of the phasing line produces a uni-directional pattern. I hope this helps. 73, Dave, N3HE ** uncrossed will make it a double-lazy-H ;o) "wildboy" wrote in message oups.com... I want build a 8jk antenna, but i don't find a good project on internet. Can anyone help me? |