> 70ft vert x4 22ft wires =22.8 loop Radres
> 70ft vert x4 45deg 28ft wires= 18.4 loop Radres
> 60ft vert x4 29ft wires=18.6 loop Radres
> 99ft vert x0 hat=18.3 loop Radres
>
> A 70 foot vertical with four 45deg hat wires is equal to a 99ft vertical
> for loop radiation resistance. A 60 foot vertical with four flat hat
> wires is equal to the same.
Hi Tom & all,
a 45 degrees inclination is acceptable with relatively tall antennas but not
so much with shorter ones.
With shorter radiators such an inclination (slope), and using hat wires long
enough for resonance, isn't any more a smart solution in my opinion.
Already with a 50ft vertical and with an hat made of 4 wires, at 45deg
inclination the Rr nearly halves in respect to an hat
made with straight horizontal wires and is also considerably smaller (worse)
than with an hat using a 22.5 deg inclination.
This happens, of course, when the wires are made long enough to resonate the
antenna at 1840 KHz..
A short radiator already has a smaller Rr thus halving it is not the
smartest to do.
A 50 ft. tall structure with 4 wires at 45 deg has infact an Rr that could
be well comparable with ground losses when using a fair radial system.
Here's the numbers I obtained using #12 wires and a vertical equal to 50ft:
50 ft vert x4 36ft (abt.) wires no inclination = Rr 13.5 Ohm
50 ft vert x4 36ft (abt.) wires 22.5 deg incl.= Rr 11.3 Ohm
50 ft vert x4 30ft (abt.) wires 45 deg inclin. = Rr 7.1 Ohm
Obviously, with a radiator that's shorter than 50 ft problems get even more
evident.
73,
Mauri I4JMY
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