K7ITM wrote:
On Feb 14, 3:21 pm, ml wrote:
I.....verse with it; it would work to fill a

volume around the antenna. But to get the full effect, it should be a
pretty large volume, containing the electric field in the neighborhood
of the antenna. Not very practical. In coax, the electric field is
between the wires; in the dipole, it's also between the wires, but the
volume is very much larger. On the other hand, people have been
shortening resonant antennas for a long time by increasing the
inductance: thus, loading coils and "slinky" antennas.
Similarly,

people make "slow" coax by making the center conductor a helix, and
thus make delay lines.
Cheers,
Tom
ok what is a 'delay line'??

i would think that would just increase the surface area and therfore
sorta increase performance

Wikipedia gives a definition of delay line; a length of transmission
line is technically a delay line, but often for longer delays, a
special line is made in which the center conductor is a wire wound
around a core (often of the same material as the dielectric between
center and outer). The winding should be done with space between the
turns, not close-wound, to give more uniform delay versus frequency.
For a uniform TEM transmission line, the delay time is the square root
of the total capacitance between the conductors times the total net
inductance of the length of the conductors: Tau=sqrt(L*C). Many E&M
texts go into how to accurately calculate the inductance and
capacitance for coaxial line with straight conductors.

In an antenna, you can increase the inductance by adding a lumped
inductance, commonly called a loading coil, or you can replace the
straight wire with a wire formed into a helix. Google "slinky
antenna". You'll find lots of info. I'm not making any claims that a
slinky antenna is either a good antenna or a poor one; it's just one
way to make a shortened dipole or monopole antenna, or even a
shortened Yagi.

Cheers,
Tom

In the early days of computers they used to use a length of wire as
temporary memory. At the start of a store cycle a piece of data would be
input to the wire, after a period of time the data would come out and be
placed into the computation.
Admiral Grace Hopper used to give an example of time and delay in her
speeches. She would say that one day she called down to the computer
department and asked for a micro second. They sent her 1000 feet of
wire. She then called down and asked for a nanosecond, they sent her one
foot of wire. No point to this just a good story.

Dave N