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December 6th 04, 12:33 AM

In article ,
(RHF) wrote:

= = = Telamon wrote in message
= = =

...
In article ,
Monroe wrote:

In an effort to construct a loop with very fine wire, I glued down
25-conductor flat computer cable about a wooden hoop then laid the
wire down in the spacing between each of the comp cable wires. Nice
and neat; evenly spaced. But is there a problem with having this
layer of discrete wires positioned about the coils of the loop?

This will mess up the loop. Why don't you just use the wires in the
computer ribbon cable itself by connecting the end of the previous turn
with beginning of the next.

Another solution is to not use the computer ribbon cable just the wire.
The wire can be neatly positioned on the wood frame by cutting equal
spaced groves in it front to back that the wire can fit into.

TELAMON,

* The easier solution to "Equal Spacing" of the 'individual' Turns of
a Loop Antenna using small wire and narrow spacing is to use #30 AWG
Magnet Wire and 10-15 Lb Mono-Filament Fish Line. The very 'narrow'
Equal Spacing is accomplished by the Thickness of the Fish Line.
Take the Magnet Wire and the Fish Line together side-by-side and Wrap
them on you Loop Form; tightly and closely maintaining a uniform wrap.

* The simpler solution to "Equal Spacing" of the 'individual' Turns
of a Loop Antenna is to use Insulated #24 AWG Solid Hook-Up Wire.
The 'small' Equal Spacing is accomplished by the "Double" Thickness
of the side-by-side Insulation that covers the Wires. Take the
Hook-Up
Wire and Wrap it on you Loop Form; tightly and closely maintaining a
uniform wrap.

* Another solution to "Equal Spacing" of the 'individual' Turns of
a Loop Antenna using small wire and narrow spacing is to use Insulated
#20-#22 AWG Hook-Up Wire and Nylon "Mason" Line. This gives about a
1/8"-1/10" Equal Spacing between the Wires. Take the Hook-Up Wire and
the Mason Line together side-by-side and Wrap them on you Loop Form;
tightly and closely maintaining a uniform wrap.

* A 'trick' to "Equal Spacing" of the 'individual' Turns of a Loop
Antenna using most wire smaller than #16 AWG Wire is to use the Black
"Groved" Step TREADING sold in Hardware Stores. The Treading has
"Evenly Spaced" 'groves' that are about 1/8" apart. Use the Groves
to 'create' the "Uniform Spacing" of the Loop Antenna Wires:
- Wrap the Wire in 'every' Grove for Narrow Spacing ~ 1/8"
- Wrap the Wire in 'every-other' Grove for Average Spacing ~ 1/4"
- Wrap the Wire in 'every-third' Grove for Wide Spacing ~ 3/8"
- Wrap the Wire in 'every-fourth' Grove for Very Wide Spacing ~ 1/2"
How-To-Place-the-Treading:
- Mark the Primary Edge of the Treading - The First Grove with a
Pen or Pencil for Reference as Starting Point for the Wire Wrapping.
- Cut (across) the Treading into One-Inch-Wide Strips and Trim the
Treading to the Width of the Loop.
- Box Loop - Glue the Treading to the very 'edge' of one-side of a
Corner of a "Box" Loop Frame; and do the same uniformly at the other
three Corners.
- Round Loop - Glue the Treading at Four (90*), Six (60*) or Eight
(45*) "Spots" around a Circular Loop Frame.
- PVC Pipe Loop - Glue the Treading to the out-side-surface of each
of the Spreaders of the PVC Loop Frame; and do the same uniformly at
the other Spreaders.

The basic idea of using a uniform insulator along with the conducting
wire to maintain spacing is a good idea but it does have one drawback
and that is the inter winding capacitance will increase.

Air has a dielectric constant of ~ 1 and anything else excepting vacuum
will be higher. The advantage of cutting groves in the spacing arms is
that the material, say wood, is between the windings at only four spots
for a box loop and 99.999% of the turn length has air between the
windings.

If you have trouble reaching the high end of the tuning range you might
want to consider this.

--
Telamon
Ventura, California