On Thu, 14 Aug 2003 20:32:24 GMT, the captain
wrote:

the captain sails new and unexplored waters, most people already use
wire. it's time for new adventures.

The "captain" has no idea what he's doing. This ain't no beverage
you're making. I'm not saying you won't hear some interesting things
with it, but it won't have the properties a real Beverage with plain
wire would have.

73,


Jake Brodsky, AB3A
"Beware of the massive impossible!"

"the captain" wrote in message
...
hey bud, "ain't" is not proper english. there could be children learning
english from this thread

the big C




Ain't's almost OK with the good folk at dictionary.com:

"Even educated and upper-class speakers see no substitute in folksy
expressions such as Say it ain't so and You ain't seen nothin' yet."

http://dictionary.reference.com/search?q=ain%27t

Too bad the online version of the OED is a subscription service. I'm sure
they'd have even more to say about this fine colloquialism.

Frank Dresser

In article bU6"the captain"
@bgtnsc0 4-news.ops.worldnet.att.net,
"the captain" wrote:

would a slinky make a good travel antenna ? take it to the park or
camping and stretch it out? seems like it would be quick to put away and

Well, what I use is a dipole made with a pair of 3 meter lengths of wire
connected to a plug. The wires have alligator clips at the ends, mostly
just as a handy way to string them up, but I also sometimes clip them to
available metal objects. It's not hard to coil up.

The Slinky is fun, but calculations of its performance relative to a
straight wire are discouraging. Below resonance it's just a hunk of wire,
only slightly better than a straight wire of similar length. It's a
relatively efficient antenna at resonance (which for a "standard" slinky
is around 7 MHz), but above resonance it is less efficient than a straight
wire of the same length. For HF reception, efficiency generally matters
most at the higher frequencies where the Slinky's efficiency is in
decline.

--
| John Doty "You can't confuse me, that's my job."
| Home:
| Work:

JD,

"It's a relatively efficient antenna at resonance (which for a
"standard" slinky is around 7 MHz)"

So what would you think the relative 'resonant frequency' of the small
diameter and shorter Slinky Jr. be ? ? ?


~ RHF
..
..
= = = "John Doty"
= = = wrote in message ...
In article bU6"the captain"
@bgtnsc0 4-news.ops.worldnet.att.net,
"the captain" wrote:

would a slinky make a good travel antenna ? take it to the park or
camping and stretch it out? seems like it would be quick to put away and

Well, what I use is a dipole made with a pair of 3 meter lengths of wire
connected to a plug. The wires have alligator clips at the ends, mostly
just as a handy way to string them up, but I also sometimes clip them to
available metal objects. It's not hard to coil up.

The Slinky is fun, but calculations of its performance relative to a
straight wire are discouraging. Below resonance it's just a hunk of wire,
only slightly better than a straight wire of similar length. It's a
relatively efficient antenna at resonance (which for a "standard" slinky
is around 7 MHz), but above resonance it is less efficient than a straight
wire of the same length. For HF reception, efficiency generally matters
most at the higher frequencies where the Slinky's efficiency is in
decline.

In article , starman
wrote:

John Doty wrote:

In article ,
wrote:

So what would you think the relative 'resonant frequency' of the small
diameter and shorter Slinky Jr. be ? ? ?

One of the peculiar things about a small diameter helix is that over a
rather wide range of pitch angles and diameters it resonates at
approximately twice twice the frequency that it would if it were
stretched out straight.

Is there a formula that applies to a Slinky?

Not hard to calculate this with a helix of at least three turns will
result in an impedance of ~ 140 ohms:

Wavelength = WL

Diameter of a turn .35 WL
Circumference of a turn 1.1 WL
Pitch ~ 13.5 deg
Spacing between turns WL tan 13.5 deg (about 1.35 WL)

Seen from the side the helix should look like a sine wave proportional
to the size of an EM wave it is made for in air. From this you can
probably guess how it works.

A typical slinky would work in the microwave range.

I consider the helix to be a basic antenna in that it emulates the way a
wave travels in space. A reference dipole is like space terminated to a
passing wave.

--
Telamon
Ventura, California