Monoband 3 el. yagi for 17 Mt
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After many years of home-self construction and many pounds of aluminium passing under my hands, my skill has been making progress either concerning type and weight of the material used. Also tuning up was sensibly improved. The antenna we are now talking about , mewly born, is nothing but a classical 3-element yagi for 18 Mhz.. Dimensions have already been explained it the dedicated page. I will now talk only about its mechanical features. Material and dimensions: All the elements have a central part with a diiam. of 30 mm. decreasing down to 16 mm to the necessary length.
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Boom is a square pipe 40X40 mm., two or more pieces in order to attain the nessary dimensions, the single parts will be connected with a diam. 35x35 mm. tube, inserted inside. The whole thing will be fixed by using bolts by 6 mm. diam The base of the single elements will consist of a plate 1oox10x25 mm. drilled in order to accepts clamps, type TV, 6 mm. diam in order to fix the boom base. These clamps shall be made with a 6 mm. rod and bent to accept our central element. As far as the dipole is concerned , it must be centrally insulated, so manage to have a PVC tube of aceptable diam. on which the central element of the radiator will be inserted.
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The support between boom and mast will be a plate with a diam. of 100x10x350 and should be drilled in order to accept the 60 mm. clapms (already seen before) plus 2 extra clamps with a diam. by 60 mm. (similar to the ones used to fix the exhausting pipe of your car) and will fix the whole attachment to the mast so making it also stronger. The single elements will be be assembled with the usual clapms just after having made a cross cut on the top of each element. Mount the whole thing, put the baloon at the centre, tune for the desired band between SSB and CW (it works also just 1,5 Mt. from the ground) and 18 Mhz will be yours. Always at full disposal for any further information.
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(at i6DHY house installed by IK4DCS - 07/2003)
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