Dipole-2 different wire sizes?
"Ian Jackson" napisal w wiadomosci
...
In message , Rob
writes
Szczepan Bialek wrote:
napisał w wiadomości
...
Szczepan Bialek wrote:
"Ian Jackson" napisal w
wiadomosci
...
In the past, many amateurs did connect coax directly to a dipole.
And what they do if they have the monopole?
Connect it with coaxial transmission line, idiot.
If the monopole has only one radial it is exactly as the your dipole.
Right?
No. A monopole needs many radials, not one. if it has only one radial
the voltage at the end of the radial is the same as on the monopole,
and the whole thing becomes a dipole.
I think we need to avoid Szczepan's black and white (and usually
completely wrong) way of thinking about things. We need to consider "When
does a monopole become a dipole" (or vice versa).
With no actually ground connection, you could have a nominal monopole with
(say) only one radial (eg an extremely badly radiating quarterwave radial
running horizontally at ground level, and a quarterwave radiating element
going vertically (or semi-vertically) upwards. If you then raise the
radial so that it starts to radiate better - or if you raise the whole
antenna system away from the ground - it will then increasingly become a
dipole.
Real dipole has symmetric voltages not in phase (180).
Of course, while a monopole with a single ground-level radial (and no
ground connection) would work quite well, it would not be as good as if
you added more (preferably spread out) radials. And the more radials you
add - especially if any overall radiation from the radials is negligible -
makes the antenna system more definitely a monopole than a dipole.
I have found that in Polish description the dipole used by radio-amateurs
consists of the radiator and the counterpoise.
It is explained that it is geometrically symmetric.
Does anybody use the real dipole?
S*
|