Topband: Shuntfeeding

[Maurizio Panicara]

>
> Also, regarding radials:  I've been told dozens of things about radials
over
> the years.  I won't quote them all here, but these are a few that concern
> me:
>
> The more the better?

Yes, but beyond a certain limit the obtained improvement is totally
neglectable.

> All must 1/4 wavelength long?

Not necessarily.
The radials should be long enough to reach areas where the current is
highest or still considerable.
If a radiator is quite short then it's important the to have more radials
below the antenna than few very long ones.
If a radiator electrical lenght is beyond a quarterwave the point od maximal
current density is away of the antenna base and the radials should be
longer, possibly increasing their number (splitting) away of the antenna
base.

> Doesn't matter how long they are, some may be very long or very short?

Just explained.

> To be effective they must be #8 wire or larger?

They should be thicker where the current is higher, practically speaking
anything that's reasonable for the actual currents works.

> Each must be terminated with a ground rod?

Why ?

> Each must be as straight as possible?

The shape is not important if they reach the proper distance.

> They don't need to be straight, they can curve or go around houses, etc?

While it's not a must to have a ground plane made of straight wires, it's
not the best if some object lay under the antenna and *collect* the current
instead of the ground plane.

> Radials must be evenly distributed around the vertical antenna?

Something symmetrical would play better.
By the way, with elevated radials (it's a counterpoise, not a GP) a total
symmetry is a stringent requirement if one wants to prevent they radiate.

73,
Mauri I4JMY