N6RK wrote ..."About 10 years ago, I built a 1/4 wave 20 meter vertical
with 32 1/4 wave radials and compared it to a 1/2 wave 20 meter vertical
with 4 4 foot radials. No difference at all. So the 1/2 wave
vertical not only didn't require more radials, it basically didn't need
any radials at all. ".....
The fact that your results found them to be equal is interesting but not
something that can be used as data. Evaluating the difference between
verticals is not easy when the expected answer is probably less than 3
dB. It requires a very controlled test. On-the-air evaluation is very
difficult when QSB can be 50 times greater than what you are trying to
measure (that's 20 db vs 3 dB). Regardless of the results, it also
requires data to determine how the answer is affected by the radials and
the ground, or if it is affected by something else.
..."The comment was specific to 160 meters and was in reference to
adding horizontally polarized radiation to a vertical."....
Well if you had said it was in reference to a 10 meter antenna, I might
have agreed with you. High angle radiation on that band never returns
to earth. On 160 it does. The horizontal wire alters the radiated
pattern producing increased signal strength at close distances. That is
not everyone's goal for 160 but for those who desire it, that radiation
cannot be considered "useless or ineffective".
Broad generalizations about antennas is difficult because there are so
many variables that can be juggled to alter the performance, and of
course that performance is always a measure of what you want the antenna
to do. You can't even make a statement that a T antenna has more low
angle gain than an inverted L without citing a specific example and
explaining the details of the patterns of both. It's a little like
comparing apples and oranges. It requires a few words. In the L's best
direction the performance will be probably be close and because of that,
the radiation resistance and radial system along with ground
characteristics and the exact antenna dimensions will probably determine
the winner. (although likely not by much). And I'm not going to add
the rest of the words to describe the other things that happen.
Jerry, K4SAV
Rick Karlquist wrote:
> K4SAV wrote:
>
>> I often see the quote that making a vertical (or inverted L) longer than
>> a quarter wave reduces ground loss because the radiation resistance goes
>> up. I would like to believe that, because that is what I am using for
>> an antenna, but I don't want to kid myself. I'll admit that the
>>
>
> About 10 years ago, I built a 1/4 wave 20 meter vertical with
> 32 1/4 wave radials and compared it to a 1/2 wave 20 meter vertical
> with 4 4 foot radials. No difference at all. So the 1/2 wave
> vertical not only didn't require more radials, it basically didn't
> need any radials at all. (Yes I know WWVH says they needed
> radials on their halfwave vertical. Not my experience.)
>
>
>> I was going to let the "useless horizontal waves" comment pass, but
>> while I'm at it I may as well take a swipe at that too. Most people
>> that use dipoles, inverted vees, and Yagi's don't think they are useless.
>>
>> Jerry, K4SAV
>>
>
> The comment was specific to 160 meters and was in reference to
> adding horizontally polarized radiation to a vertical. Maybe that
> wasn't clear. If the only antenna you have on 160 is a dipole,
> it is better than nothing. Compared to a vertical, it is generally
> ineffective. As with everything, there are "corner cases". I
> use only Yagi's above 4 MHz. Propagation is different up there.
>
> Rick N6RK
>
>
>
>
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