The antenna will be designed to operate in the 10, 20, 40 and 80 m bands.The simulations are focused to obtain the impedance and the radiation patterns of the antenna in those bands.In this design the working bands are 10, 20, 40 and 80 meters.
Each arm of each dipole is connected with the arms of the other dipoles in the same side. The resonance condition for each band may be quite difficult to achieve, so it is recommended to use an antenna tuner. The most adequate transmission line is the 75 ohm twin lead, but you may use also 50 ohms or 75 ohms coaxial cable. The reality is, every single antenna I have ever built with insulated wire ends up having to be shorter than calculated and usually less than 95 too. There was a lot of talk about what the guy should use, including copperweld, FlexWeave (my favorite), and plain, old, 14-ga. This factoid has been part of ham radio lore for a long time. The second result was a posting by Reg, G4FGQ, titled Velocity factor of an insulated wire on radiobanter.com. Heres what he posted. It is much less than the pruning sometimes done for end effect which is usually unnecessary anyway. Mmana Gal Dipoles Full Effect ItFor the permittivity of the insulation to have full effect it would be necessary to completely fill the infinity of space with the insulating material. Unfortunately, neither the website URL or e-mail address on his QRZ.Com page are working. Mmana Gal Dipoles How To Get HoldIf you know how to get hold of him, please e-mail me with the details. Perhaps some note of that should be made on his QRZ.Com page. Also if you use insulated wire an inverted V lets the RF out better than a dipole. In getting parts, I am unable to find any plastic spacers to keep the coil evenly spaced. Is there such for sale Are there some tips on how to keep a coils spacing while winding Any help appreciated. Were into new territory here, but the kids are having a blast. By the way NASA, the US military and renowned antenna expert L. B. Cebik, W4RNL all whole heatedly disagrees with your flawed assertion that the effects of wire insulation on antenna wire is insignificant. The program (MoxGen) he was using to calculate the dimensions only calculates dimensions for bare wire. Since he was using insulated THNN wire I suggested he reduce all dimensions by 3 percent. The end results His Moxon tuned up a whopping 630Khz below the calculated frequency for bare wire. This mistake cost him his day off, He had to pull the antenna down off the mast, disassemble the entire antenna and re-trim all the dimensions. EZNEC predicted that the frequency using insulated wire would come out 630Khz low and thats exactly where it came out. When modeling with say Eznec you should use a dielectric constant of about 5 and an insulation thickness of about.8 MM for THNN wire. ![]() The dialectic effect of Insulation on wire being relegated to Folk lore and wives tails really since when has science and engineering been reduced to being called lore, This whole thread is a perfect example of the dumbing down of amateur radio. If youre supposed to take these things into consideration, how do you do so If its a matter of science and engineering, there should be some equations somewhere.
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