RadioBanter - Grounding

One thing you have to remember about the arguments between various antenna
types; dipoles, longwires, yagi's. etc. These are all "tuned" antennas
(even a random longwire) and their maximum gain is only evident in a single
band. While a large horizontal loop of "one wave" in length (example: 80
meters circumference = one wavelength at 3.5MHz) will perform equally to a
"half wave" dipole (i.e. 40 meters long) AT THE SAME HEIGHT.

Where the large horizontal loop shines is at all frequencies about its "one
wave" length. The large horizontal loop of a theoretical length of 80
meters in circumference will exhibit the characteristics of a dipole at ANY
frequency above 3.5MHz. Whereas a halfwave dipole will only exhibit equal
performance at 3.5MHz and its multiples (i.e. 7MHz, 14MHz, 21MHz).
Everywhere else the dipole will exhibit a loss compared to a large
horizontal loop.

The characteristics of our theoretical 80 meter large horizontal loop are
"relatively" flat all through the spectrum with much less peaks or valleys
compared to a dipole all the way up to at least 30MHz.

It is the ideal antenna for general SWL and HF utility monitoring because
its performance is equal all across the shortwave spectrum. Consider its
performance similar to a UHF/VHF discone antenna. It exhibits a flat
response, no gain or loss (relative to a half-wave vertical), from
50-900MHz! That is about 1000MHz! - that is very "broadbanded."

"RHF" wrote in message
ups.com...
MK - By Definition "In-the-Attic"

In-the-Attic = Limited Space and Antenna Size

In-the-Attic = Usually means that the Wire Antenna Element
is 12 Feet to 18 Feet High above AGL for a single story house.
Maybe twice that for a two story house or split-level condo.

NOTE - For a Shortwave Listener's (SWL) "Receive Only" Antenna
that is designed to "Fill" the Available Space : Whether these
Antennas are : a Random Wire; a Dipole, or a Loop they are
not "Cut' for any specific Wave Length and Frequency; they
are simply Random Wire Antennas

IN-THE-ATTIC AND ATTIC SIZE :

In a 30 Foot by 40 Foot size Attic a basic straight Random
Wire Antenna can be 30 Feet along the short side; 40 Feet
along a the long side; or 50 Feet across a the diagonal.

In a 30 Foot by 40 Foot size Attic a simple straight Wire
Dipole Antenna can be 30 Feet along the short side; 40 Feet
along a the long side; or 50 Feet across a the diagonal.

In a 30 Foot by 40 Foot size Attic a common Wire Loop
Antenna would be : 30 Feet along one short side; 40 Feet
along one the long side; 30 Feet along the other short side;
40 Feet along the other long side; for a total of 140 Feet
around the Attic [.]

MK - It should be self-evident that " there is simply more
Wire in the Air. " and that is all I said and meant to say.

RELATIVE ANTENNA NOISE :
" Equally as low Noise due to the natural properties of a Loop. "

The usual ascertion is that a Dipole Antenna has a Lower Noise
Factor (Property) then the same Length Random Wire at the
same Height; all other things being equal : Balun / No Balun;
Coax Cable / Twin Lead / Ladder Line; ETC.

The Horizontal [Flat] Loop Antenna has the same Lower Noise
Factor (Property) then the Dipole Antenna has in the same
relative Available "In-the-Attic" Space : All other things being equal
:
Balun / No Balun; Coax Cable / Twin Lead / Ladder Line; ETC.

There is Nothing to be gained or lost by using the Dipole or Loop
Antenna in the Attic Noise Wise : But with the Loop Antenna more
Wire is in the Air which can result in more Signal from the Antenna.

ANTENNA APERTURE :
RHF Said - " Greater Antenna Aperture {Signal Capture Area}
due to the natural shape and size of a Loop in any given space;
with less apparent signal fading. "

MK - You model two 80 Meter Band Antennas; a Half-Wave Dipole
Antenna and a Full-Wave Horizontal Loop Antenna and say that they
are the same with little measurable difference between the two. "OK"

Again here my beginning point is "In-the-Attic" were both the Dipole
Antenna and the Horizontal [Flat] Loop Antenna are using the same
Available Space and are in fact simply two 'random wire' antennas
that happen to be laid-out in the confines of the Attic. Here the 50
Foot long Dipole Antenna with lets say 50 Square Foot of Signal
Capture Area has less potential as an Antenna : Then the 140 Foot
long Horizontal [Flat] Loop Antenna with lets say 120 Square Foot
of Signal Capture Area that has more potential as an Antenna.
To my simple way of thinking relative size and area does matter.
? Now is this Theoretically or Machine Measurable - Most Likely.
? Now is this Discernable by the Shortwave Listener (SWL) - Maybe.

THE CRAP SHOOT :
MK you say : "Basically, it's a crap shoot." "I run the dipoles."
RHF says : For an In-the-Attic Antenna "Crap Shoot" I prefer
the Horizontal [Flat] Loop Antenna - It's a matter of choice.

MY INTUITIVE STATEMENT ABOUT VERTICAL LOOP ANTENNAS :
RHF Said - " Intuitively I would think that for a Vertical Loop Antenna

to perform up to its potential the maximum Length-to-Height (Aspect)
Ratio would be about 4:1 or 5:1 ."

Again here my beginning point is "In-the-Attic" most every Attics
that I have been in is Longer and Wider then they are High {Tall}.
So 'if' we are trying to Maximizing the Size of the Vertical Loop
Antenna then a simple Circle or Square would not produce as much
Wire Length and Combined Area as a Rectangle or Triangle using
up the Available Space inside the Attic. The added comment about
the Length-to-Height (Aspect) Ratio being about 4:1 or 5:1 was to
not have the Vertical Loop become to flat compressed and effectively
become a fat Folded Dipole Antenna of sorts.

RESTATING MY CONCLUSIONS {NON-TECHNICAL OPINIONS} :
For a "Receiver Only" Antenna being used by a Shortwave Listener (SWL)
The Horizontal [Flat] Loop Antenna used In-the-Attic may/could/should
perform better then the simple Dipole Antenna with potentially Higher
Signal Levels; the same relative Noise Level; and less apparent Fading.

STAYING ON MESSAGE - THIS CONVERSATION :
MK - You appear to be a "Technical Person" and that is well and good.
However, I am for the most part a non-technical person who simply tries

to Keep It Simple And Practical [KISAP]. For me these Conversations
can be an interesting exercise in restating my simple minded opinions :

But for you these Conversations may turn out to be an exercise in
futility
- a Fools Errant so to speak.

MK - Part of my 'iane' signature { I Ain't No Elmer }
Means : I Don't Get Techincal - Because - I simply am not smart
enough to try and WOW anyone with the all that math or science.

MK - I Am Glad We Had This Talk :o)

kisap - keeping it simple and practical ~ iane ~ RHF
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All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL ANTENNAS GROUP = http://tinyurl.com/an6tw
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Some Say: On A Clear Day You Can See Forever.
I Believe : On A Clear Night You Can Hear Forever
. . . and Beyond , , , The BEYOND ! ! !
With a Shortwave Listening Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL ANTENNAS GROUP = http://tinyurl.com/an6tw
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