[TowerTalk] FW: 40 meter delta

[Marinus Loewensteijn]

> Marinus, > > As often is the case on this reflector it sounds as if you received more > private responses than public. If you would be so kind as to summarize them > and post to the reflector then that data would be available for others to > use in the future. > > Good luck with your project. > > 73/Patrick > W7TMT Patrick and others who responded privately: A number of the replies were supporting the Delta loop. It was noted that if it is a Delta and fed at the apex then the polarisation would be horizontal whereas for DX work vertical is much better. Also the vertical polarisation seems to be less influenced by being close to the ground. A coaxial dipole was also suggested and a pdf document was forwarded dealing with reduced sized delta's. Coils can be used to reduce the size of a delta but only up to a certain limit. Afterwards the losses in the coil get too big. Capacitance loading in the bottom wire (apex at top, antenna corner fed at the bottom wire) or using two stubs in this lower wire all work. If a jumper is placed in the center of the antenna then it can be opened and the antenna can be used as a folded dipole on 80. I still like my own initial idea of a half wave L, fed at the top in the corner (basically a dipole where the legs are at a 90 degree angle with each other) and have the "vertical leg" slope around 30 degrees and then add the missing link between the ends of the legs making it into a loop. I am thinking of making it a 3/4 wave loop - this should work with a decent atu. May use 300 tv wire to get close to the house and then use a 1:4 Guanella balun and then coax to get inside. Late Cebik (SK) spoke highly of the top corner fed half wave L. This will give me both local (horizontal) and DX (vertical) capability at not too high a penalty. Making it into a loop should reduce the noise level and give harmonic operation. Still pondering about all the replies, many thanks for all the contributions. 73, Marinus, ZL2ML
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