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ok guys lets get them gears turning!i dont know if this type of thread has been covered but here we go.first of all i recently made this top hat out of some old antenna parts, i went by the the super penetrator 500 specs of 19 inches,correct me if i am wrong or 9.5 mounted.now i have some more old antenna parts including smaller radiator elements that would fit right in the top of that maco to bring it up to the 22-23 feet .64 wave. i am not expecting to make a p/500 but maybe close and better than what i got.can i do this and readjust the tap point and loop for swr.

oops.

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I don't think it's going to make a big difference, but a good cap-hat won't have any sharp/pointy ends/edges. That shape deals with corona and end-effect voltages. Round shapes are better than pointy ones.
Unless you just want to duplicate a particular antenna's design, there is not 'set' length for a cap-hat, it's one of those use whatever is necessary kind of things. Don't want, or can't make an antenna longer? Then make the cap-hat bigger, amounts to the same thing.
Best place to put a cap-hat, if possible, is at the top of the antenna. Sometimes that just isn't too practical, so you get it as close as you can. With loaded antennas, you want that cap-hat above the coil as far as practical, the further above the better. Otherwise it interacts with that coil and just doesn't work as well.
And paint it orange! People don't seem to like pink much.
- 'Doc

thanks for the reply doc!i was thinking off going with purple.oh and the correct me if i am wrong part was the length on the p500 top hat, i think i read somewhere 19 inches that was just a ball park idea.i owned a avanti 101 years ago but cant remember the size of the top hat.on top of making the radiator longer i was also thinking of linking the ground planes with a piece of wire and maybe adding 4 more pieces in between the ground planes whats your thoughts on this?

ok so i went through 76 pages of antennas here and saw i was not the only one wanting to make a .64 wave maco however i did notice that every time it turned quite controversial into a debate and was never clearly answered.has anyone tried this and am i on the right track at about 22.3 feet radiator length and will i need to bake a bigger loop or will i have to just try for myself.

i have no idea whether this is correct or not, but i remember reading somewhere that the reason the maco 5/8 radiator is only 20 feet long is because the additional length is in the tuning ring.

does that make any sense to anyone that knows about these antennas?

never owned one before so ive not done too much learnin on them.
LC

__________________
"Man shall never reach the moon, for such a quantity of gunpowder would be needed as to gravely injure the crew."
~ Children's Encyclopedia, 1926

Couple of things.
If you want to add additional radials, or a wire connecting the ends of those radials, there's nothing that says it won't be a benefit. It will require that the antenna be re-tuned.
making that tuning 'ring' larger isn't going to do much good. There's no 'length' being made up for with that ring, it's used as an impedance matching device just exactly like a gamma match. Changing the length will change the impedance that 'ring' has to match to 50 ohms, so, if there's not enough 'adjustment' available to do that, yes, the ring may need to be slightly larger. But there's no direct relation between the size of the ring and the antenna's length. I've got a feeling I didn't explain that very well at all, but I can't think of another way of saying it. Oh well, it's late, I'm sick of fire-works, would swear a few of them 'crackers' were made with things with a brass shell casing, ain't had no coffee. If that don't cover the excuses, the hell with it.
- 'Doc

doc, you explained it just fine.

thanks for setting me straight on that one.
sure dont want to add to the confusion on this issue. LOL

LC

__________________
"Man shall never reach the moon, for such a quantity of gunpowder would be needed as to gravely injure the crew."
~ Children's Encyclopedia, 1926

thanks doc i guess i will go with 23 feet and go from there!to many things unclear but i am trying.basic .64 23 feet.imax radiating 22.6.penetrator 22.6 + or - 9.5 inches..64 free space 23.suggestion from another forum 22.13.my own thoughts 27.185 5/8 wave length 22.6*.015+22.6=22.95<leaning towards that number.wolf .64 22.6.is the top hat figured in?probably not!cdx has stated penetrator with 23 and change on length<good idea can always reduce length

other thing i think i figured out a99 1/2 wave,starduster 1/2 wave.now i dont know if i am learning from all this reading or getting more confused my maco is stated a 5/8 wave using the cb as a operating frequency that tells me its only 5/8 wave at around 30 mhz fully extended(ithink).imax 2000 not a .64 wave at 27.185 but the actual stated 5/8 maybe .64 at another frequency of operation.hmm getting dizzy here!