Capacitance Hat's Don't add Audio

[HomerBB]

no one is picking on the name as usual you get your panties in a bunch without knowing the whole story.

I ain't got no panties on . . ."

Now, back to the discussion.
As we've established before, this isn't personal. I just won't let anyone blindside me with unsupported claims or accusations. There is no cause to be upset with me. I am only asking for what you offered - the truth.

There was absolutely nothing in the starter post you made that supported your accusation. And, although there was nothing in the post to support what you said, there were responses to the post ridiculing Coily on the basis of that post. I may be the only one initially who asked a real question about it, though.

You said your motives were to objectively establish the truth of things. I am just asking for evidence within the post for the accusation of error. I have been by Coily's site a time of two, but I didn't memorize it, nor do I own one. You know I like to homebrew.

Now I have another question.

If the modulation/audio utilizes the carrier/signal to get to and from points A and B, then why would this statement not be true?

all I have done is created a capacitance up top! Forcing more signal/audio up top also adding exceptional receive,shortening overall height,also eliminating any chance of high wattage arcing!!

Respectfully,
Homer

 

[W5LZ]

I don't see a problem with that thingy being both a corona-ball and a capacitive-hat. Of course, the size of the thing will determine how -much- capacitance it adds. The size also determines how much voltage the thing can handle before emitting a coronal discharge. The -shape- of that thingy has more to do with the coronal discharge than it does with being a capacitive-hat. Corona-balls tend to have no points, are more of a smooth ball or rounded shape.
That 'audio ball' thing is just more oxymoron stuff...
- 'Doc

 

[Shockwave]

I didn't. I asked a question. but if you're wondering what prompted the question it was this post by SW:

I was wanting to know whether or not the ball would increase performance, or if these things are matters relating to what is performance parameters of antennas.

Homer, It depends on what your definition of increased performance is. If it applies to wider bandwidth then the answer is yes. If you mean can it equal or add to the gain of a full length radiator without the cap hat, the answer is no.

It is likely that a shorter antenna will have better performance if less electronic length was added in a center loaded inductor and more electronic length were added in the form of a top hat. That said, nothing can equal the performance of a straight radiator of equivalent wavelength.

Another funny thing I've seen one CB antenna maker throw together was the top coil loaded 1/4 wave fully equipped with a top capacitance hat. You NEVER combine these two devices with one directly over the other. To make a long story short, it's like stepping on the gas and the brake at the same time. They both cancel each other out and accomplish nothing.

 

[jazzsinger]

Another funny thing I've seen one CB antenna maker throw together was the top coil loaded 1/4 wave fully equipped with a top capacitance hat. You NEVER combine these two devices with one directly over the other. To make a long story short, it's like stepping on the gas and the brake at the same time. They both cancel each other out and accomplish nothing.

this wouldn't be the mythical merlin 55 would it?

another classic piece of cb bullshit.

 

[MrSuburban]

Homer, It depends on what your definition of increased performance is. If it applies to wider bandwidth then the answer is yes. If you mean can it equal or add to the gain of a full length radiator without the cap hat, the answer is no. It is likely that a shorter antenna will have better performance if less electronic length was added in a center loaded inductor and more electronic length were added in the form of a top hat. That said, nothing can equal the performance of a straight radiator of equivalent wavelength.

Another funny thing I've seen one CB antenna maker throw together was the top coil loaded 1/4 wave fully equipped with a top capacitance hat. You NEVER combine these two devices with one directly over the other. To make a long story short, it's like stepping on the gas and the brake at the same time. They both cancel each other out and accomplish nothing.

Agreed

 

[HomerBB]

Homer, It depends on what your definition of increased performance is. If it applies to wider bandwidth then the answer is yes. If you mean can it equal or add to the gain of a full length radiator without the cap hat, the answer is no.

It is likely that a shorter antenna will have better performance if less electronic length was added in a center loaded inductor and more electronic length were added in the form of a top hat. That said, nothing can equal the performance of a straight radiator of equivalent wavelength.

Another funny thing I've seen one CB antenna maker throw together was the top coil loaded 1/4 wave fully equipped with a top capacitance hat. You NEVER combine these two devices with one directly over the other. To make a long story short, it's like stepping on the gas and the brake at the same time. They both cancel each other out and accomplish nothing.

Thanks for the answer. I am soaking it up.

 

[BOOTY MONSTER]

this wouldn't be the mythical merlin 55 would it?

another classic piece of cb bullshit.

http://www.firecommunications.com/gr45.pdf

 

[Shockwave]

Jazz, you picked the Merlin base antenna I was thinking about in my post. Booty, you came up with the mobile version I had completely forgotten about. I haven't seen a Goldenrod 45 since it had a much smaller top loading coil many years ago. I guess the power increases over the years mandated that beefier coil. In either case, you never combine inductive reactance and capacitive reactance at virtually the same point on the radiator.

 

[BOOTY MONSTER]

but the merlin has up to 15 S-UNITS of tx gain over a big coily base antenna and jays i10k too !!! hehehehe

http://www.mauldroppers.com/showthread.php?2860-Yota-s-merlin-test-results


Timber and other Videos on StupidVideos.com

"you never combine inductive reactance and capacitive reactance at virtually the same point on the radiator."

just for the record , can you tell us why that shouldn't be done ?
thanks

 

[Shockwave]

"you never combine inductive reactance and capacitive reactance at virtually the same point on the radiator."

just for the record , can you tell us why that shouldn't be done ?
thanks

Of course Booty. Both of these devices add reactance into the system. One adds capacitive reactance while the other adds inductive reactance. Reactance is AC or RF resistance and becomes more complex when you account for how phase shifts occur when alternating currents pass through an inductor or capacitor. This gives capacitive reactance opposing properties from inductive reactance even though they are both forms of alternating current resistance.

Now if you take two devices with opposing properties and stack them back to back, what do you have? Essentially you have a cancellation of the effects both devices provide. Both can be used simultaneously on the same antenna, however the loading coil should never be placed higher then half way up the radiator if a cap hat is used. As I recall, the more separation between the two, the better they work.

 

[Shockwave]

The next logical question might be why do these two types of reactance (alternating current resistance) have opposing properties? This is due to the phase shift between current and voltage as it passes through either a inductor or a capacitor. When AC or RF passes through an inductor, the current lags the voltage by 90 degrees. This means the voltage reaches it's highest point 1/4 of the sine wave before the current hits it's peak in the cycle. In the case of the capacitor, voltage lags the current by 90 degrees and creates the opposite effect. This makes everything from certain types of induction motors to tuned circuits possible.

 

[HomerBB]

Tech Talk: Whatever capacitance any given cap hat adds, is the same no matter where it is placed. However, whether or not a cap hat increases the effective length and/or increases the radiation resistance and/or increases overall losses, depends on where (how high above the coil) the cap hat is placed. For example, when placed too close to the loading coil, the capacitance can have a detrimental affect on the coil's Q, and will indeed produce an increase in the measured input impedance. For example, the left photo* depicts a cap hat incorrectly installed. The input impedance and bandwidth will indeed increase in this example, however the changes are due to increased coil losses, and not by an increase in radiation resistance (Rr) . . .

Cap hats typically increase bandwidth. The amount of the increase is based on a myriad of factors, most of which you cannot measure directly. Here too, you have to be careful about applying a change in input impedance (SWR over any given bandwidth), as a positive indication. In fact, the bandwidth of an antenna with incorrectly mounted cap hat (directly atop the coil), will be greater than a correctly mounted one, and with far less efficiency as well.

Cap Hats

*

What da ya know, every once in a while you antenna gunslingers get it right

 

[Marconi]

i was thinking that too, [FONT=Arial,Helvetica,sans-serif]"It must Be Correctly designed,spaced,and it is extremely important that the top hat wires be symmetrical around or across the connection point."[/FONT]

taken from his own advertising yet he chooses to ignore it.

George, I don't think you'll ever realize much difference with a fix to the particular issue being discussed here. However, I do think symmetry can be important to performance, and efficiency. I've even commented myself, that the I-10K and Wolf .64 GP both have similar issues with the way they mount both the top hats and their radials for peat's-sake...no extremely important symmetry in those designs.

Could I observe the difference, NO!

I think ya'll are talking about a mobile antenna design, but when comparing Dan's 5/8 wave Enforcer GP, don't you see very good symmetry in his radial hub and matching designs, that are at best arguable in both the I-10K and Wolf .64, with the big trombone tuner and the gamma? Such issues are argued all the time about the gamma skewing the pattern when used on yagi beams, but again...IMO you'll likely never be able to measure or observe that affect.

For ya'll to argue, for example, that a 7" fork is better than a 6" fork seems petty to me.

 

[Marconi]

Tech Talk: Whatever capacitance any given cap hat adds, is the same no matter where it is placed. However, whether or not a cap hat increases the effective length and/or increases the radiation resistance and/or increases overall losses, depends on where (how high above the coil) the cap hat is placed. For example, when placed too close to the loading coil, the capacitance can have a detrimental affect on the coil's Q, and will indeed produce an increase in the measured input impedance. For example, the left photo* depicts a cap hat incorrectly installed. The input impedance and bandwidth will indeed increase in this example, however the changes are due to increased coil losses, and not by an increase in radiation resistance (Rr) . . .

Cap hats typically increase bandwidth. The amount of the increase is based on a myriad of factors, most of which you cannot measure directly. Here too, you have to be careful about applying a change in input impedance (SWR over any given bandwidth), as a positive indication. In fact, the bandwidth of an antenna with incorrectly mounted cap hat (directly atop the coil), will be greater than a correctly mounted one, and with far less efficiency as well.

Cap Hats

*

What da ya know, every once in a while you antenna gunslingers get it right

Homer, have you tried this idea yet? If so, how did it work out?

My Daddy has both the GR45 & GR50 and we find these two antennas work remarkably well as designed. It has been a while since I compared them, but I think I recall the longer and newer one seemed notably better than the original model.

 

[HomerBB]

No, I haven't tried this. They appear to be a bad design. It would be a matter ofa few minutes work to set a wire cap over a coil to do it on one of my antennas.