Sizing : The Loop Antenna -versus- the Long-Wire Antenna forShortwave Radio Listeners (SWLs)
 

Sizing : The Loop Antenna -versus- the Long-Wire Antenna
for Shortwave Radio Listeners (SWLs)
-
- On Mar 2, 1:39 pm, wrote:
- Was : 1000 Foot Longwire Antenna's
- http://groups.google.com/group/rec.r...720818dc91ccc8
- - On Mar 2, 11:18 am, wrote:
- - Was : 1000 Foot Longwire Antenna's
- - http://groups.google.com/group/rec.r...2b3bf9dd74739a
-

SIZING : The Loop Antenna -versus- the Long-Wire Antenna
OK - My Ground Rules : No Scientific Claims or Justification plus
very little everyday Math : Cause I Ain't a Scientific Type of People

LOOP ANTENNA :
With Single Turn Loop Antennas it is Aperture {Area Size}
as an Order-of-Magnitude that matters.
http://en.wikipedia.org/wiki/Order_of_magnitude
10 Inch Square Loop = 100 Square Inches [1X=BaseLine]
18 Inch Square Loop = 333 Square Inches [3X]
32 Inch Square Loop = 1000 Square Inches [10X]
6 Foot {58- Inch} Square Loop = 3333 Square Inches [33X]
8 Feet 4 Inches Square Loop = 10,000 Square Inches [100X]
15 Foot 3 Inches Square Loop = 33,333 Square Inches [333X]
26 Feet 4 Inches Square Loop = 100,000 Square Inches [1000X]

Loop Antenna Observations and Comments :
a. The 10~12 Inch, to 18~22 Inch, to 32 Inch~One Metre Square
numbers show why many home made Box Loop Antennas
are made in these Size Increments to Capture a significant
amount of more Signal over the next smaller Size.
aa. Most of the small commercial AM/MW Loop Antennas
are in the 10~12 Inch Size range. {Portability & Ease-of-Use}
b. Also the 10 Inch to 18 Inch to 32 Inch {One Metre} Square
Loop Antenna Elements can still be used Indoors.
c. Taking the next step-up in the Sizing Order-of-Magnitude
requires going to Six and Eight Foot Loop Antenna Elements;
and then the Size would require that they be located Outside
the Building/House.
d. A 15 Foot Square Wire Loop Antenna Element is still
Do-Able -but- the 26 Foot Size best lends itself to the
Triangle Shaped Loop Antenna Element with a single Tall
support for the Apex of the Loop and the base parallel to
the surface of the ground.

VIEWING - The Loop Antenna's Wire Antenna Element
in the Local Space :
The Loop Antenna has a Center that remains the same as the
Size of the Loop Antenna's Wire Element gets bigger and gets
smaller. The Loop is a Balance Antenna with respect to the
Local Noise RFI/EMF Environment : Often Noise Artifacts at
one point* in a Loop Antenna are cancelled-out by the same
Noise Artifact at an equal-and-opposite point* in a Loop Antenna.
* The Location and Proximity of the Noise Source relative
to all parts of the Loop Antenna Element is another Factor
to consider here.

A General Statement can be made that a Loop Antenna can
be "Scaled-Up" an Order-of-Magnitude or Two {10X~100X}
to increase it's RF Signal Levels -with-out- The same relative
increase in the Order-of-Magnitude of the Noise that it also
picks-up.
-AS- The Loop Antenna gets bigger the number of
points-of-balance increase to continually Balance-Out
the Loop Antenna Element
-BUT- With the bigger Loop the 'differential' between parts of
the Loop and specific local, nearby and very-nearby Noise
Sources increases : Thus increasing the potential Noise
Pick-Up of a bigger Loop.
Revised/Adjusted View : The bigger Loop Antenna can in-fact
provide greater Signal Levels with only smaller increases in
the relatively Signal-to-Noise Ratio : Based-on the Increase in
it's Physical Size; coupled with the increase in the Physical
Differential between all parts of the Loop Antenna Element
and each of their physical proximity to nearby sources of
Noise.

LONG-WIRE ANTENNA :
With Single {Linear} Long Wire Antennas it is Total Length
as an Order-of-Magnitude that matters.
3 Foot {36 Inch} Whip Antenna = 3 Linear Feet [1X=BaseLine]
10 Foot Wire Antenna = 10 Linear Feet [3X]
30 Foot Wire Antenna = 30 Linear Feet [10X]
100 Foot Wire Antenna = 100 Linear Feet [33X]
300 Foot Wire Antenna = 300 Linear Feet [100X]
1000 Foot Wire Antenna = 1000 Linear Feet [333X]
3000 Foot Wire Antenna = 300 Linear Feet [1000X]

Long-Wire Antenna Observations and Comments :
a. Starting with the common built-in Whip Antenna which
is roughly about 3 Foot long as the Baseline Reference.
b. At just 10 Feet of Wire we see a small noticeable relative
increase in the Signal Level can be achieved within the
Room {Indoors}.
c. In the range of 30 Feet a full Order-of-Magnitude can be
realized in a relatively small Outside Space. {Backyard}
d. However the next Step-Up to around 100 Feet does
actually require a large Outside Space for the Long-Wire
Antenna Element. {Large Backyard}
e. To achieve significant results beyond 100 Feet sizing
up to the next Orders-of-Magnitude requires 300 Feet
and 1000 Feet of Open Space for the Long-Wire Antenna
Element which eliminates these "Next-Steps" for most
Shortwave Radio Listeners (SWLs). {Being Much Bigger
Than the Average Size Backyard}
f. 300, 1000, and 3000 Foot Wire Antennas will show
directional characteristics; particularly at Frequencies
where their Lengths are in the order of 1.5 to 3 Wave
Lengths or more.

VIEWING - The Long-Wire Antenna's Wire Antenna Element
in the Local Space :
The Long-Wire Antenna has a Center that moves as the
Size of the Long-Wire Antenna's Wire Element gets longer
and gets shorter. The Long-Wire is an Un-balance Antenna
with respect to the Local Noise RFI/EMF Environment : Local
Noise Artifacts at one point* in a Long-Wire Antenna are NOT
cancelled-out by the same Noise Artifact at an equal-and-opposite
point* in a Long-Wire Antenna -because- That Point Does Not
Exist.
* The Location and Proximity of the Noise Sources relative to
all parts of the Long-Wire Antenna Element is a Key Factor
to consider here.

A General Statement can be made that a Long-Wire Antenna
can be "Scaled-Up" an Order-of-Magnitude or Two {10X~100X}
to increase it's RF Signal Levels =WITH= The same relative
increase in the Order-of-Magnitude of the Noise that it also
picks-up. Along it entire Length Long-Wire Antenna the can
Equally "Pick-Up" both RF Signal and RFI/EMF Noise.
-BUT- As the Size of the Long-Wire Antenna gets longer; the
Center {Average Distance} of the Long-Wire Antenna's Wire
Antenna Element also moves.
-IF- The shorter Long-Wire Antenna's Center {Average Distance}
is closer to the Building/House and therefore closer to the
RFI/EMF Noise Environment : Then the Wire Antenna Element
is Fully Enveloped {Saturated} in the Noise.
-NOW IF- The longer Long-Wire Antenna's Center {Average
Distance} is farther-away from the Building/House and therefore
farther-away from the RFI/EMF Noise Environment : Then the
Wire Antenna Element is No-Longer Fully Enveloped {Less
Saturated} in the Noise.
Revised/Adjusted View : The longer Long-Wire Antenna can
in-fact provide greater Signal Levels and a relatively improved
Signal-to-Noise Ratio : Based-on the Increase in it's physical
Size and the Shifting {Moving} of it's Center away from
Sources of Noise.

COMMON-SENSE-SAYS :
Clearly a 1000X Order-of-Magnitude Loop Antenna would be :
Easier-to-Build and Use-Up-Less Land than a 1000X
Order-of-Magnitude Long-Wire Antenna.

Note # 1 - At Resonance and the Resonance Node Points :
1/4 WL, 1/2 WL, 1 WL, 1.5 WL, 3 WL . . . the Size of the
Antennas Measured in Feet does not matter as much as
the 'relative' Size of the Antennas in these Wave-Lengths.
http://en.wikipedia.org/wiki/Resonance
http://en.wikipedia.org/wiki/Wavelength

Note # 2 - The Relative Changes in Size with respect to
the Earth; the Solar System; and the Universe are not a
significant factor for this discussion.
http://en.wikipedia.org/wiki/Planetary-size_comparison

Note # 3 - Noise Artifact : RF Signal present when RFI/EMF
impacts a Wire Antenna Element anywhere along it Length.

Loop Antenna Conclusion : For most AM/MW Radio Band
Listeners (BCLs) DXers the One Metre Loop Antenna is
adequate to meet their needs.

Long-Wire Antenna Conclusing : For most Shortwave Radio
Listeners (SWLs) an Antenna Length between 30 and 100
Feet that fits in their Space available will be adequate to
meet their needs.