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Equipment / Re: Vertical antenna build questions
« on: June 05, 2020, 1242 UTC »
Transmitting and receiving are reciprocal. What benefits one, benefits the other.
Its been my experience that in a practical sense one will SEE the benefits of more radials in the reduced bandwidth of the antenna in use as a transmitting antenna (as losses decrease) more than you'll hear the difference. You'll also SEE that adding more beyond a certain practical point (8-10) becomes less and less impactful to the efficiency . (It's kind of like asymptotically approaching a limit- there's a big diff when you start, but that really tapers off quickly). You can see this with the narrowing of low SWR bandwidth. Its pretty impressive ! :-) Short, long or in between length radials, it's hard to tell much practical difference given all the other variable involved in setting up an antenna in all but a uniform, idealized antenna range.
I'd not overdesign on paper chasing that limit, but put up the 1/4 wave with 6-8 radials under it, then play with the spacing, position and length of the director/reflector. I think you'll notice FAR more of an effect messing with that , than the radials (beyond a few). I'd get the geometry correct, then add radials, as the directivity and S/N will come from geometry of the array , while the radials will "just" affect the overall, broad band loss.
Its been my experience that in a practical sense one will SEE the benefits of more radials in the reduced bandwidth of the antenna in use as a transmitting antenna (as losses decrease) more than you'll hear the difference. You'll also SEE that adding more beyond a certain practical point (8-10) becomes less and less impactful to the efficiency . (It's kind of like asymptotically approaching a limit- there's a big diff when you start, but that really tapers off quickly). You can see this with the narrowing of low SWR bandwidth. Its pretty impressive ! :-) Short, long or in between length radials, it's hard to tell much practical difference given all the other variable involved in setting up an antenna in all but a uniform, idealized antenna range.
I'd not overdesign on paper chasing that limit, but put up the 1/4 wave with 6-8 radials under it, then play with the spacing, position and length of the director/reflector. I think you'll notice FAR more of an effect messing with that , than the radials (beyond a few). I'd get the geometry correct, then add radials, as the directivity and S/N will come from geometry of the array , while the radials will "just" affect the overall, broad band loss.