A question was asked about what use was 'Q'
To me Q showed its value with the introduction of the National Radio
HRO
a receiver with 2 RF stages and 3 IF stages. This receiver as
excellent receiver because it recognised that the mixture of
frequencies produced not only a desired frequency but also many other
undesired frequencies and while we used to use spark gap tranmissions
that were extremely wide the introduction of higher density spectrum
use produced a zillion frequency mixtures which are of no use.
The HRO by decreasing the spectrum received to exclude errant
frequencies increased the Quality (Q) of signal reception by
expanding the difference in signal level received compared to the
level of errant frequecies received ( noise). This difference can be
analogous to the gain of an antenna
where noise introduced into a receiver must be overcome by the
required signal gain or there is no communication. The HRO did this by
its then unheard of
3 I.F. stages which provided a low noise floor. So Q does have a use
as it is inextricably bound to the Quality of communications and
everything that goes with it, it cannot be ignored.

More to come, let the attack begin.

Art

There is QRS Quality of Received signal. Then there is Q, which is used in
Filter design, and also there is Loaded Q, also used in filter, or
selectivity design. Q is related to the losses of a tuned section, the L and
C, R, the more R the less Q, less selectivity, more stages needed. There is
a formula to calculate Q in terms of L,C and R. Remember the old TRF stages
in early AM radio? More the better, and there is a formula for calculating
the series of selectivity stages of equal stages. The more stages of
selectivity, or more narrow the selectivity, more broadband noise rejection,
the more sensitive the radio is, and sounds better.



"Art Unwin KB9MZ" wrote in message
...
A question was asked about what use was 'Q'
To me Q showed its value with the introduction of the National Radio
HRO
a receiver with 2 RF stages and 3 IF stages. This receiver as
excellent receiver because it recognised that the mixture of
frequencies produced not only a desired frequency but also many other
undesired frequencies and while we used to use spark gap tranmissions
that were extremely wide the introduction of higher density spectrum
use produced a zillion frequency mixtures which are of no use.
The HRO by decreasing the spectrum received to exclude errant
frequencies increased the Quality (Q) of signal reception by
expanding the difference in signal level received compared to the
level of errant frequecies received ( noise). This difference can be
analogous to the gain of an antenna
where noise introduced into a receiver must be overcome by the
required signal gain or there is no communication. The HRO did this by
its then unheard of
3 I.F. stages which provided a low noise floor. So Q does have a use
as it is inextricably bound to the Quality of communications and
everything that goes with it, it cannot be ignored.

More to come, let the attack begin.

Art

"Art Unwin KB9MZ" wrote in message
...
A question was asked about what use was 'Q'
To me Q showed its value with the introduction of the National Radio
HRO
a receiver with 2 RF stages and 3 IF stages. This receiver as
excellent receiver because it recognised that the mixture of
frequencies produced not only a desired frequency but also many other
undesired frequencies and while we used to use spark gap tranmissions
that were extremely wide the introduction of higher density spectrum
use produced a zillion frequency mixtures which are of no use.
The HRO by decreasing the spectrum received to exclude errant
frequencies increased the Quality (Q) of signal reception by
expanding the difference in signal level received compared to the
level of errant frequecies received ( noise). This difference can be
analogous to the gain of an antenna
where noise introduced into a receiver must be overcome by the
required signal gain or there is no communication. The HRO did this by
its then unheard of
3 I.F. stages which provided a low noise floor. So Q does have a use
as it is inextricably bound to the Quality of communications and
everything that goes with it, it cannot be ignored.

More to come, let the attack begin.

Art
Q is a numerical representation of how well a "real world tuned circuit"
compares with a therorectically perfect tuned circuit. The theroretical
circuit having no losses due to resistance or radiation.

9
Tho coupling was used for IF circuitry in the late thirties to
achieve
high Q it was more than 40 years before coupling made an appearance on
a macro
scale on the transmission side. On warships it obviously essential
that transmission were clean but on large ships there were many
structures that would reradiate a signal using energy from a
transmitter. It was found that if a loop was placed near such
structures energy would pass between the structure
and the loop circuit via back EMF such that via coupling the now
parallel circuit would move the offending signal( See ARRL
antenna/handbook)
..Around this time the loop anteena made an appearance where a short
element was end fed an placed close to a loop containing a capacitor.
Again EMF was at work where two frequencies could be made one and
where a slight change in the loop curcuit allowed the combined
frequency to be moved.
At the same time Moxon introduced what was called the disappearing
inductance
(antennas for all locations) where he fed a normal dipole instead of a
short member as in a loop antenna and placed it in close proximity to
a loop circuit.
In this case tight coupling was required for a single frequency
emmision such that the loop
became a physical part of the dipole even tho two circuits remained.
Again the capacitor in the loop allowed resonant transmissions over
at least an octave Art took this further by close coupling more loop
dipole elements in yagi beam form. Art became more interested in the
single element form because the combination loop dipole could supplant
the traditional trapped dipole but with the realisation that more gain
could be attained because the radiation was of collinear form and thus
looked for different ways of feeding the dipole combination instead of
a delta feed.
It was at this point that Art
made the loop in ladder form since frequency span depended on the
loops periphary as well as changing the feed to one of a coupled
circuit form.

More to come but special thanks to the earlier posters who added more
insight
to the values of Q.
Let the attack commence
Art















































i













i

Art, KB9MZ wrote:
"---special thanks to the earlier posters who added more insight to the
values of Q."

Art`s posting is a misrepresentation of the way antennas work in my
opinion. Q of an antenna from an impedance standpoint is related to how
narrow its bandwidth is over a small frequency range. Its Q at resonance
is:

2 pi x total energy stored by antenna / energy dissipated per cycle.

Attempts to maximize gain while minimizing size of an antenna generally
reduce its bandwidth while also reducing its radiating efficiency. See
"Antennnas" by Kraus, 1950, pages 433-434.

Coupling is another word for mutual impedance. The mutual impedance
between two antennas is defined by:

Z12 = E2/I1.

This is the ratio of the voltage induced in antenna #2 by the current in
antenna #1. See Terman`s 1955 edition page 894 for details.

Antennas or elements of arrays can be coupled and must be if a parasitic
array is to be effective. Spacing and tuning of the elements is
essential to performance. Unless elements are near resonance, reactance
is too high for significant current flow. Also, which side of resonance
parasitic elements are tuned to determines which direction radiation
will be reinforced in and in which direction radiation from the direct
radiator and re-radiation from the parasite will tend to cancel.

Terman says on page 905 of his 1955 edition:
"The exact effect on the directional pattern that is produced depends
upon the magnitude and phase of the induced current, i.e., upon the
spacing of the antennas and upon the tuning of the parasitic antenna.
For example, if the driven and parasitic antennas are relatively close
together and parallel, then the current induced in the parasitic antenna
will be such as to reduce the strength of the radiation in the direction
of the parasitic antenna when the latter is resonant at a lower
frequency than that being transmitted. If resonant at a higher frequency
than is being transmitted, the parasitic antenna acts as a "director"
and tends to concentrate the radiated field in its direction."

The information above all came from books by famous authors. We can`t
and don`t live long enough to make all the mistakes for ourselves.

Best regards, Richard Harrison, KB5WZI

When Art used a combination loop dipole as a three element form of Yagi it
was really an error as he has lapsed back into wavelength style thinking
where as the loop/dipole were coupled elements that formed a collinear array
which obviosly could not be used succefully in this arrangement. Art then
changed the beam aproach by removing the capacitance from the element loops
and then coupled the loops in series form with the dipoles attached
which did not require a specified spacing between the elements which then
formed a nice beam via close coupling. The beam was fed via a delta feed but
Art wanted a broader frequency range. He did this by feeding the coupled
array with a separate dipole with a delta feed and placed this close to and
parallel to the leading dipole /loop which formed a capacitive coupling to
the antenna array. What happened here is that energy was fed to the delta
feed dipole and then the energy travelled along the dipole and then
transfered to the antenna array at the point of best match. This broadened
the frequency span of the array in a similar way to varying the connection
point of a delta fed antenna such that the operating frequency even when
changed was at the array resonant point. So upto now Art had made a
loop/yagi dipole with a ladder type loop that could be used in excess of one
octave as well as making a coupled array with a moveable resonance but with
the declining sunspot cycle comming decided to work on a 160 meter dipole.
He made the element as long as possible and then added the loop with a
variable capacitor, he also fed the dipole/loop antenna with a capacitive
coupled delta fed dipole that also contained a variable capacitor and then
realised that if he added a variable inductance to the loop dipole he would
in reality be duplicating the 'T' circuit that was used as a inbuilt tuner
in a solid state tranciever where he could disconnect the 'T' circuit in the
radio and use the controls to control both vaiable capacitors such that the
input impedance would always be resistive regardless of the spacing of the
former capacitive coupling which was now an inductive coupling. Immediately
it was seen that if the capacitances were made as small as possible (2 pF or
less)and left fixed, together with an ideal spacing between the feed and the
combo dipole the band pass of the antenna was around 5 to 7 Khz and could be
moved anywhere on the band by just varying the inductance. Varying the
inductance was done quite easily by the addition of a variometer to the main
inductance. The antenna worked extremely well at around 50 watts in the
horizontal position together with a few db down on the sides. Since Arts
tower was a fold over he was also able to operate the antenna in the
vertical position with a low operating angle because the antenna being
collinear in form was less dependent on ground conditions or the need for
ground radials.
Attacks can now begin ,.......the next report will detail what the computor
says about its characteristics on 160M and what an overlay on a beverage
pattern shows which will surprise many plus details how the antenna can be
reformed to provide a cluster of radiators and confirm again that one could
have a antenna array
that is not controlled by wavelength, with a high Q bandpass that not only
was moveable but always operated at a resonant point and where the delta
feed was devoid of radiation i.e. lossless feed and match.
Still going......
Art Unin KB9MZ.........XG























i













i

Before I finish up with a comparison between a rotating combo dipole and
the weel known beverage antenna for 160M there are a few loose ends to tie
up and ofcourse I will not be describing
the clustered array types.
Moxons book came at the right time for me as I wanted an antenna to reflect
somewhat a transceiver where the antenna design reflected a moveable
bandwidth of a consistant Q and not one where a radio "scans" frequency
response as in a spectrum analyser. The Moxon book gave the answer that I
wanted to read to give me further encouragement, It refered to where ZUKOV
stated that radiation theoretically could emanate from a point and thus one
could read in to that statement that length (wavelength) should not be the
focal point for antenna design after all it would be very difficult to find
anything in a book that focussed around
length. If a point radiation can be realised then length was not a primary
factor instead it was the passive loads that was carried by 'Length". When
Moxon chose the twenty metre length for his
resonator or combo dipole this blurred the impact with respect to what
lengthand constituent passive loads meant,so he chose a random length of
random diameter for his arrangement, after all to factor in the many
resistances involved in radiation without a computor in reverse complex
circuitry aproach would have taken a hundred years. Fortunately he hit on a
suitable size radiator and he was able to procede even tho he made poor
choices later.
The initial arrange ment is shon in his book plus interesting longhand
formula with respect to coupling and corresponding
antenna performance data. Members of the attack group also found an old page
of mine which descibes my interpretations and they also have referred to a
couple of write ups that I did in patent form that clearly shows the
arrangement as did many drawing I made for this newsgroup. Nobody was able
to duplicate Moxons work hich led to the formation of a attack group, I
theorise that the reason that no one could do it was because of a
fascination for the EZNEC program which tho one time a leader in computor
analysis was quickly outpaced by present day modern designs.
The EZNEC program really revolves around providing characteristics around a
previously designed antenna only and not the best arrangement that can be
obtained. For best antenna available one needs the option of assigning
variable values for a design together with large point of moments
assignments so that not only close coupling could be performed with accuracy
but length could be of secondary importance to lumped and distributed
passive components both of which can now be variable. To accomplish what
Moxon did is impossible to duplicate if one ignores distributed loads in a
parallel configuration. Another thing that escaped the naysayers was that
talk of lumped loads in a radiating array placed them in a fixed mind
position where they still hung on to a wavelength design and put these
lumped loads at the feed point to represent an external matching system
which defeats the total intent of a parallel circuit
radiating antenna which provided high Q signal passage which does not
require an external matching system which is known to be lossy for large
size antennas.
The next post will be the last post for the moment because clusterred
antenna design is still ongoing. I have chosen the 160 mtre rotatable dipole
as a base as the initial designs of parallel circuitry revolved around bands
that have now declined. I have chosen to compare it with a simple beverage
antenna even tho this
\beverage is not used as a transmitting antenna but for its listenning
abilities. I might add at this point that when I rotated my
loop/dipole antenna from the horizontal position to the vertical position I
did not get the expected ground noise addition that I expected. This I
attributed to the coupling function of the antenna
which I believe has the ability to remove extranious noise.
Have at it 'experts" you should now be able to portray what Moxon achieved
by the correct use of computorised antenna
programs now knowing the truth of prior efforts that substantiated the
saying of "Garbage in equals garbage out" especially in the attack mode when
one is inclined to listen only to that he wants to hear or substitute for
what he thinks he should have heard.
Art Unwin KB9MZ....XG

On Wed, 17 Mar 2004 18:00:49 GMT, "aunwin"
wrote:

"Garbage in equals garbage out"

Hi Art,

As has been consistent throughout, you have yet to reveal ANY design
specification and you have entirely refused to offer ANY results from
this "superior" software you promise proves all these claims you've
pulled out of a hat. You have never demonstrated proficiency with any
software package, so your biased claims are suspect and the quoted
statement above is especially meaningful. Mark had to work long and
hard to get a faint model of your statements, which you now disavow.
As Jaro pointed out, you can achieve any results through carefully
omitting important details, or guessing at others.

73's
Richard Clark, KB7QHC

"aunwin" wrote in message news:ln06c.30814 to the

COMPUTOR COMPARISONS

ROTATABLE LOOP/DIPOLE VERT LOOP/DIPOLE BEVERAGE

10 DEG -13 -5 -9

20 DEG -8 -3 -7

30 DEG -5 -3.3 -6.5

40 DEG -2.4 -4 -8

50 DEG -1.8 -6 -13

60 DEG -0.8 -8 -30

70 DEG -0.6 -11

80 DEG -0.0 -15

90 DEG -0.0

NOTE OUTSIDE CURVE = ZERO
0dB = 2.15dBi Frequency 1.9 MHz

All above perfect ground
Rotatable dipole @ 65 feet
Vert Dipole 2 feet above ground
Beverage 10 feet above ground
Note that Beverage has beam pattern with good f/b
Dipoles basically circular pattern and good for transmit and receive

ART UNWIN KB9MZ

On 24 Mar 2004 17:51:31 -0800, (Art Unwin KB9MZ)
wrote:

"aunwin" wrote in message news:ln06c.30814 to the

COMPUTOR COMPARISONS

Note additional column at end for comparison:

ROTATABLE LOOP/DIPOLE VERT LOOP/DIPOLE BEVERAGE KB7QHC Vertical

10 DEG -13 -5 -9 +4.66 dBi

20 DEG -8 -3 -7 +4.21 dBi

30 DEG -5 -3.3 -6.5 +3.44 dBi

40 DEG -2.4 -4 -8 +2.29 dBi

50 DEG -1.8 -6 -13 +0.68 dBi

60 DEG -0.8 -8 -30

70 DEG -0.6 -11

80 DEG -0.0 -15

90 DEG -0.0

NOTE OUTSIDE CURVE = ZERO
0dB = 2.15dBi Frequency 1.9 MHz

All above perfect ground
Rotatable dipole @ 65 feet
Vert Dipole 2 feet above ground
Beverage 10 feet above ground
Note that Beverage has beam pattern with good f/b
Dipoles basically circular pattern and good for transmit and receive

ART UNWIN KB9MZ

Hi Art,

I don't see to much to crow about. What point were you trying to
illustrate? You don't really describe the antennas very well, but it
doesn't seem to matter much given the numbers above. It does
illustrate how extremely poor dipoles do at 160M. A simple vertical
seems to be considerably more effective than the three antennas you
offer. By my comparisons up to 50 degrees, the KB7QHC Vertical has at
LEAST 2.4 dB more gain than ANY of the three; at a more interesting
angle of 10 degrees, the vertical shows an easy gain of +9 to +17 dB.

As for being on topic, what has this got to do with Q?

73's
Richard Clark, KB7QHC