Generally,

Because there is a good agreement between
theoretical [analysis/design] computations
and measured [explanation/prediction] data.

Sincerely,

pez
SV7BAX
TheDAG

"SpamLover" wrote in message om...
| Purdon my deep egnorance, but, why do we tend to use thin conductors
| for antennas? I know of only few counter-examples, all at VHF and
| above:
| - a discone can be made of sheet metal, rather than thin radials
| - a log-periodic broadband dipole can be made as an etched spiral
| pattern on PCB (and I guess it can't be made with constant section
| conductors at all...)
|
| I know that things get more complicated at higher frequencies, what
| with slot antennas & suchlike.
|
|
| A connected curiosity is regarding short active receiving antennas on
| HF. My concern is putting together an efficient, mobile mounted,
| all-band HF receiving antenna. If we use short whips, they show an
| extremely high impedance and require a carefully designed matching
| amplifier. At such high impedance levels, a broad 3-30MHz bandpass
| filter may not be easy to design - so I have been told.
|
| But I wonder - why not use 1-2 sqft of conductive surface instead, e.g
| PCB or big bore copper rainpipe, worked against the car body?
|
| I just ran an unscientific experiment. I grounded a pocket HF
| receiver to a steel-topped table, and balanced a steel pot lid on the
| top of its collapsed whip antenna. Signals were booming. A 10" PCB
| disk, placed 5" above the steel roof of a car shouldn't be much
| different.
|
| Comments?