Capacitance Hat's Don't add Audio

[HomerBB]

MrCoily, . . .

you have the ONLY capacitance hat in the known universe that increases performance!!!

. . .

"Properly placed, they (capacitance hats) can effectively increase the electrical length, by moving the current maxima toward the center of the antenna.

Tech Talk: . . . the following assumes the cap hat is mounted at the very top of the antenna, and thus the noted increase in input impedance is a positive one, not a negative one.

Because the effective electrical length is increased, the radiation resistance also increases, albeit slightly. Physically increasing the whip length will do the same, but there is a practical limit to how long an HF mobile antenna can be (height above ground). By adding a cap hat, the overall length can remain the same (or less if the cap hat is large enough), while radiation resistance increases. " http://www.k0bg.com/caphats.html

?

 

[Moleculo]

"Properly placed, they (capacitance hats) can effectively increase the electrical length, by moving the current maxima toward the center of the antenna.

Tech Talk: . . . the following assumes the cap hat is mounted at the very top of the antenna, and thus the noted increase in input impedance is a positive one, not a negative one.

Because the effective electrical length is increased, the radiation resistance also increases, albeit slightly. Physically increasing the whip length will do the same, but there is a practical limit to how long an HF mobile antenna can be (height above ground). By adding a cap hat, the overall length can remain the same (or less if the cap hat is large enough), while radiation resistance increases. " Antenna Cap Hats

The capacitance hat increases performance on a physically short antenna as compared to one that is the same length without. It does not increase performance as compared to a full sized 1/4 wave mobile.

 

[mrcoily]

one other thing my shorter antenna beats the 102" whip so why is that...hmmmm ill be waiting for a lengthy post on 1/4 wave 102 inch actaully 108 inch performance that cant be beat by a coil due to losses in the loading sections..thus the caphat..well you guys can getter done..till next time.

 

[Moleculo]

I know exaclty whats going on thats the whole point.

We keep asking and you keep evading the question. Please tell us exactly what is going on.

...keep digging lol.

If you would give us some facts and information that is actually useful, we would not be digging. You're still evading...

 

[Shockwave]

Mr. Coily, you admit to using a very poor location for tuning your antennas 5 years ago and today you still think your loaded antenna can produce more field strength then an unloaded 1/4 wave. I'd say little has changed in that time.

 

[HomerBB]

Mr. Coily, you admit to using a very poor location for tuning your antennas 5 years ago and today you still think your loaded antenna can produce more field strength then an unloaded 1/4 wave. I'd say little has changed in that time.

"A uniform current flowing along the length of the (1/4٨)
whip is an idealized situation, however, since the current
is greatest at the base of the antenna and goes to a minimum
at the top. In practice, the field strength will be less
than that given by the above equation, because it is a function
of the current distribution on the whip. . .
the current is not uniform on a whip
antenna . . . The net result
is that most of the antenna current returns to ground near
the base of the antenna, and very little near the top.

Two things can be done to improve this distribution
and make the current more uniform. One would be to
increase the capacitance of the top of the antenna to
ground through the use of top loading or a capacitance
hat, . . . The other method is to place the loading coil
farther up the whip, as shown in Fig 7, rather than at the
base. If the coil is resonant (or nearly so) with the
capacitance to ground of the section above the coil, the
current distribution is improved as also shown in Fig 7.
The result with both top loading and center loading is
that the radiation resistance is increased, offsetting the
effect of losses and making matching easier."

ARRL Antenna Handbook ch.16

 

[loosecannon]

MrCoily, you would be wise to continue to avoid answering my posts.

by addressing my implications you will be forced to take a side, have an opinion, or god-forbid actually attempt to explain your understanding of something.

we are all smart enough here to realize exactly why you answer posts in the way you do.

its all about "copy and paste". you know full well that once you post something in an attempt to defend your claims, that your argument will be torn to pieces, and the entire conversation will be "copied and pasted" all over the place.

this would eventually hurt your sales because there are only so many CB forums, and once your BS is out there on all of them, coming from your own keyboard, you will be done.

how many amps do you think AMPOWER sells these days?
i can tell you for sure that its nowhere near the number he used to sell before this, and other forums got ahold of him.

the part you dont seem to realize is that its not us you have to worry about.
its all the guests and members "sandbagging" here and just reading.

we have given you the rope, and you are doing with it exactly what the others have done.

remember how everyone used to believe that cutting your coax would match your antenna?
well internet forums like this one have all but cleared that one up.
wild mobile antenna claims are next.
LC

 

[Shockwave]

"A uniform current flowing along the length of the (1/4٨)
whip is an idealized situation, however, since the current
is greatest at the base of the antenna and goes to a minimum
at the top. In practice, the field strength will be less
than that given by the above equation, because it is a function
of the current distribution on the whip. . .
the current is not uniform on a whip
antenna . . . The net result
is that most of the antenna current returns to ground near
the base of the antenna, and very little near the top.

Two things can be done to improve this distribution
and make the current more uniform. One would be to
increase the capacitance of the top of the antenna to
ground through the use of top loading or a capacitance
hat, . . . The other method is to place the loading coil
farther up the whip, as shown in Fig 7, rather than at the
base. If the coil is resonant (or nearly so) with the
capacitance to ground of the section above the coil, the
current distribution is improved as also shown in Fig 7.
The result with both top loading and center loading is
that the radiation resistance is increased, offsetting the
effect of losses and making matching easier."

ARRL Antenna Handbook ch.16

This article is comparing loaded antennas to other loaded antennas. It does not compare the loaded antenna to the unloaded. The first paragraph seems to refer to a base loaded 1/4 wave since the second paragraph suggests it's performance can be improved by moving the coil higher or adding a capacitance hat. Neither one of these actions can increase the performance of the unloaded 1/4 wave or make the loaded antenna equal to or greater then the unloaded antenna.

 

[HomerBB]

This article is comparing loaded antennas to other loaded antennas. It does not compare the loaded antenna to the unloaded. The first paragraph seems to refer to a base loaded 1/4 wave since the second paragraph suggests it's performance can be improved by moving the coil higher or adding a capacitance hat. Neither one of these actions can increase the performance of the unloaded 1/4 wave or make the loaded antenna equal to or greater then the unloaded antenna.

Thanks, Shockwave for this answer. I appreciate it. Not too many in this thread so far.
I am asking sincere questions. In this part of the ARRL Antenna Handbook it speaks of a full 90° mobile antenna.
Is this not a 1/4ƛ whip?
Unless a case can be made for it not being a 1/4ƛ whip, there is a lot of credibility at stake here for the argument that a properly made center-coiled antenna can not result in improvement in performance over a 1/4ƛ whip.

I am one of those doing more reading than writing here, and I see a lot of arguing that leaves more questions unanswered from both sides of the debate than are answered. I really would like more than stuff like "everybody knows . . "., and " . . .widely accepted" kind if assumptive statements. Or will I, as in other places when someone asks for answers be arrogantly told to "get my learn on"?
If I am to derive any truth from this debate I'll need to have something more than taunting and put-downs to read.

If you're going to take the Draino from the baby, give him a safe toy in its place. . . and that is common sense practice among informed parents. . .

Thanks, everyone,
Homer

ARRL Antenna Handbook - ch 16
"The current varies with the cosine of
the height in electrical degrees at any point in the base
section. Therefore, the current flowing into the bottom
of the loading coil is less than the current flowing at the
base of the antenna.
But what about the current in the top section of the
antenna? The loading coil acts as the lumped constant
that it is, and disregarding losses and coil radiation, maintains
the same current flow throughout. As a result, the
current at the top of a high-Q coil is essentially the same
as that at the bottom of the coil. This is easily verified by
installing RF ammeters immediately above and below the
loading coil in a test antenna. Thus, the coil “forces” much
more current into the top section than would flow in the
equivalent section of a full 90º long antenna. This occurs
as a result of the extremely high voltage that appears at
the top of the loading coil. This higher current flow
results in more radiation than would occur from the
equivalent section of a quarter-wave antenna. (This is true
for conventional coils. However, radiation from long thin
coils allows coil current to decrease, as in helically wound
antennas.)



The cross-hatched area in Fig 10 shows the current
that would flow in the equivalent part of a 90º high
antenna, and reveals that the degree-ampere area of the
whip section of the short antenna is greatly increased as
a result of the modified current distribution. The current
flow in the top section decreases almost linearly to zero
at the top. This can be seen in Fig 10.
The degree-ampere area of Fig 10 is the sum of the
triangular area represented by the current distribution in
the top section, and the nearly trapezoidal current distribution
in the base section. Radiation from the coil is not
included in the degree-ampere area because it is small
and difficult to define. Any radiation from the coil can be
considered a bonus."

 

[wahlrite]

Basically the idea of a capacitance hat is to make up the length needed for resonance while limiting the vertical height. It can be a disc or wires, mesh etc anything that will add capacitance to the antenna.

To reduce Q in an antenna system, we can either improve the ground properties or add a capacitance hat above the coil. It will act like a big capacitor in lowering the resonant frequency of the antenna


Starting simple - a vertical antenna is in reality a simple series R-L-C resonant circuit. The vertical wire, rod, or tube is the inductor, L. The same vertical mast, in combination with the radials, forms the capacitor, C. Completing the circuit is the antenna radiation resistance Ra. Antenna radiation resistance varies with the length of the antenna. It shrinks as antenna length shrinks.



*******************************************
Big Bully Comp antenna

Mr. Coily Sales Pitch Version from his website

The "Original" Audio Ball top hat!!


"""Dictionary Version"""
Capacitance hat - This is a device sometimes found at the end of an element. It can be a cross, a disk, a ball, a loop, or just about anything conductive. It makes the element behave as if it is longer, maybe 10%-30% longer than it really is. It can save space with Gains in performance! It must Be Correctly designed,spaced,and it is extremely important that the top hat wires be symmetrical around or across the connection point.

*********************************************************************


Here is the web site Mr coily gleaned his information from and he conviently added his spin on it, and he is calling it a dictionary definition? It is a HD TV web Page that he added


Glossary A to F

"Capacitance hat - This is a device sometimes found at the end of an element. It can be a cross, a disk, a ball, a loop, or just about anything conductive. It makes the element behave as if it is longer, maybe 10%-30% longer than it really is. It can save space with almost no drop in performance. Capacitive hats are uncommon in TV antennas. (The Channel Master 3671B has six capacitive hats.)


*************************************************************

Contrary to belief a Top Hat/Cap Hat does nothing for the Audio. The term Audio Ball came from guys who run alot of power which can create a Plasma at the end of the antenna from the sharp edge. You would be able to hear a persons voice. Putting a round ball on the end will eliminate a plasma from forming.


"When buying a antenna don't beleive this hype"

hey mr suburban,
Do people on this forum really believe that an antenna alone can really add or take away audio from a signal ?

I have heard of antennas having gain in power and improperly tuned antennas having a reduction in gain, but never a antenna adding or subtracting audio alone.

Funny what some people will believe.

 

[mrcoily]

if that was an issue..i would not play with you guys on here really....if they have questions they email me or call i have plenty work load all the time i dont have to fall into your guys games...they know where go i have 5 dealers..so if you have any other questions let me know..5039306007...mrcoily@aol.com...busy day for me.

 

[Shockwave]

Thanks, Shockwave for this answer. I appreciate it. Not too many in this thread so far.
I am asking sincere questions. In this part of the ARRL Antenna Handbook it speaks of a full 90° mobile antenna.
Is this not a 1/4ƛ whip?
Unless a case can be made for it not being a 1/4ƛ whip, there is a lot of credibility at stake here for the argument that a properly made center-coiled antenna can not result in improvement in performance over a 1/4ƛ whip.

I am one of those doing more reading than writing here, and I see a lot of arguing that leaves more questions unanswered from both sides of the debate than are answered. I really would like more than stuff like "everybody knows . . "., and " . . .widely accepted" kind if assumptive statements. Or will I, as in other places when someone asks for answers be arrogantly told to "get my learn on"?
If I am to derive any truth from this debate I'll need to have something more than taunting and put-downs to read.

If you're going to take the Draino from the baby, give him a safe toy in its place. . . and that is common sense practice among informed parents. . .

Thanks, everyone,
Homer

ARRL Antenna Handbook - ch 16
"The current varies with the cosine of
the height in electrical degrees at any point in the base
section. Therefore, the current flowing into the bottom
of the loading coil is less than the current flowing at the
base of the antenna.
But what about the current in the top section of the
antenna? The loading coil acts as the lumped constant
that it is, and disregarding losses and coil radiation, maintains
the same current flow throughout. As a result, the
current at the top of a high-Q coil is essentially the same
as that at the bottom of the coil. This is easily verified by
installing RF ammeters immediately above and below the
loading coil in a test antenna. Thus, the coil “forces” much
more current into the top section than would flow in the
equivalent section of a full 90º long antenna. This occurs
as a result of the extremely high voltage that appears at
the top of the loading coil. This higher current flow
results in more radiation than would occur from the
equivalent section of a quarter-wave antenna. (This is true
for conventional coils. However, radiation from long thin
coils allows coil current to decrease, as in helically wound
antennas.)



The cross-hatched area in Fig 10 shows the current
that would flow in the equivalent part of a 90º high
antenna, and reveals that the degree-ampere area of the
whip section of the short antenna is greatly increased as
a result of the modified current distribution. The current
flow in the top section decreases almost linearly to zero
at the top. This can be seen in Fig 10.
The degree-ampere area of Fig 10 is the sum of the
triangular area represented by the current distribution in
the top section, and the nearly trapezoidal current distribution
in the base section. Radiation from the coil is not
included in the degree-ampere area because it is small
and difficult to define. Any radiation from the coil can be
considered a bonus."

This article makes sense. However, it's an inaccurate leap to assume it to mean that the loaded antenna offers more gain then the straight 1/4 wave whip. It says "the coil “forces” much more current into the top section than would flow in the equivalent section of a full 90º long antenna." I was not able to find any reference that this increases gain or field strength over the unloaded 1/4 wave.

Think about this, if it could improve performance over the unloaded antenna, wouldn't we be seeing more loading take place in antennas that are designed with gain in mind? For example, why not take this theory and apply it to all Yagi beams? Surly if this change in current distribution provided an advantage in gain someone should hurry up and apply it to 11 meter 8 element beams.

I'll give you this, if your antenna is mounted in a poor location on your vehicle that blocks much of the base of the antenna, you might see an improvement with the center loaded antenna. Therefore it's the location that gives the antenna it's advantage over the unloaded one and not that the loaded antenna has any more gain. Roof mount the full length antenna for parking and talking and no loaded antenna is going to beat it.

I also see flaws in the picture used to illustrate the current distribution on the full length 1/4 wave. Look at the shaded area representing the current in the top section of the unloaded antenna. Assuming the current distribution is highest at the base and continues a similar rate of reduction as we reach the tip, that shaded area does not line up with the base current of 1 amp as shown with the loaded antenna. In fact if you follow the same angle down to the base it shows little more then half the current of that being applied to the loaded antenna. Not sure what to make of that.

 

[HomerBB]

This article makes sense. However, it's an inaccurate leap to assume it to mean that the loaded antenna offers more gain then the straight 1/4 wave whip. It says "the coil “forces” much more current into the top section than would flow in the equivalent section of a full 90º long antenna." I was not able to find any reference that this increases gain or field strength over the unloaded 1/4 wave.
. . .

I'll give you this, if your antenna is mounted in a poor location on your vehicle that blocks much of the base of the antenna, you might see an improvement with the center loaded antenna. Therefore it's the location that gives the antenna it's advantage over the unloaded one and not that the loaded antenna has any more gain. Roof mount the full length antenna for parking and talking and no loaded antenna is going to beat it.

Okay, but could we not then make an additional case for when the loaded antenna might outperform a whip in the same location?
For instance on a tall SUV the whip likely would out perform a well designed loaded antenna, but on a low riding sedan the loaded antenna would put more radiation at the upper 15° of the antenna, an area where the longer whip is less effective, giving the loaded antenna the advantage. In the graphic the shaded area clearly shows advantage in radiation strength for the loaded antenna well along its upper length.
I know most are saying the whip in any case outperforms the loaded antenna, but unless the radiation strength of an antenna means something other than what affects output/field strength I have much more to learn than what I was thinking.

The ARRL Handbook said - "the coil “forces” much
more current into the top section than would flow in the
equivalent section of a full 90º long antenna. This occurs
as a result of the extremely high voltage that appears at
the top of the loading coil. This higher current flow
results in more radiation than would occur from the
equivalent section of a quarter-wave antenna."

You said

Think about this, if it could improve performance over the unloaded antenna, wouldn't we be seeing more loading take place in antennas that are designed with gain in mind? For example, why not take this theory and apply it to all Yagi beams? Surly if this change in current distribution provided an advantage in gain someone should hurry up and apply it to 11 meter 8 element beams.

Yes. I get this. On the other hand, Yagis are arrays of dipoles, which we are told already have the least current at the center point of the elements with the maximum at the ends. Perhaps this is a determinative factor? This is explained for why the grounding of the feedline of a gamma-matched Yagi should be made at the center point.
I would think it is the nature of the beast in every case.

I feel I am the least knowledgeable of folks to ask these things, but it is where this thread is leading me, and I need answers. Even homebrewers ought to care what they are doing is worth the doing.

 

[HomerBB]

It says "the coil “forces” much more current into the top section than would flow in the equivalent section of a full 90º long antenna." I was not able to find any reference that this increases gain or field strength over the unloaded 1/4 wave.

Are you suggesting the full 90° whip is not a 1/4ƛ whip? I am asking, not debating.

 

[mrcoily]

like i said looks great on paper real nice graph and everything when you add all your numbers...but the coil still beats it been proven a million times.also if you move your h1 and h2 you will see better gains.steel whips make good stinger.you guys need to build a couple thousand antennas then you will see what works..the books are a good start computer programs help but that dont touch real world hands on.dont have tp try to school me i have what i need thanks..have great day..live well play hard and dont forget to get out and do it not preach it.all my antennas work as claimed.