Capacitance Hat's Don't add Audio

[Marconi]

76Q, here are some variations for radiator and top hat lengths for a 1/4 wave radiator. I used slanted down radials and one model that is full length and slanted down radials, and one model that is full 1/4 wavelength using 4 x 108" horizontal ss radials.

I also have a model of a simulated mobile, but I don't think the pattern is near what you might expect, so I didn't include it. I'm not even sure it is a good model. It shows to be workable however. I used the 4 horizontal radials and made 2 x 6" x 4' and 2 x 6" x 8'. I will work with it a bit and if it looks promising, I post it later. This may prove to be futile however, because mobiles have a very unpredictable ground plan with variations and curves that are irregular and may be difficult for me to model.

The numbers at the end of the captions are the length in inches for the radiator and the top hat including a little space for the feed point hub.

View attachment Top Hats various sizes.pdf

 

[BOOTY MONSTER]

anybody ever seen a top-hat on a commercial television or radio broadcasting antenna ?
i haven't , but i'm guessing the station and their advertisers want to reach every potential customer . if a top-hat will increased their broadcasting range or decrease the wind load and keep the same performance why wouldn't they use them ?

 

[mackmobile43]

anybody ever seen a top-hat on a commercial television or radio broadcasting antenna ?
i haven't , but i'm guessing the station and their advertisers want to reach every potential customer . if a top-hat will increased their broadcasting range or decrease the wind load and keep the same performance why wouldn't they use them ?

No I haven't, because cap hats serve on in the receive stage of antennas performance right? so why would they need one?

It may help the antenna to think it's longer than it is and really serves no purpose in the antennas tx performance or they would have them on a 102'' whip.

Is someone gonna make an issue of the coronal ball being a form of cap hat?

 

[Captain Kilowatt]

anybody ever seen a top-hat on a commercial television or radio broadcasting antenna ?
i haven't , but i'm guessing the station and their advertisers want to reach every potential customer . if a top-hat will increased their broadcasting range or decrease the wind load and keep the same performance why wouldn't they use them ?

I used to run a station on 1450 KHz that had an eight foot diameter top hat.The station originally went on the air in 1945 just after the war and the antenna was a 96 foot high 4 inch diameter steam pipe with four parallel lengths of #6 copper wire running the length to aid in continuity.The top hat was referred to as the bicycle wheel at the top. The top hat was to add extra loading to the short antenna and make it easier to tune and a bit more broadbanded. In 1986 we moved he TX site and put up a proper 1/4 wave single tower for an antenna. While the 96 foot mast was not all that ideal for 1450 KHz in an area rapidly growing up with houses it did work like a charm on 80m and 160m before we took it it down after having activated the new site. It now continues to work rather well as a couple clothesline poles and an axle or two as well as a pole or two for a couple homemade trailers.

Many AM sites on the low end of the band used top hats and most longwave antennas or VLF antennas are actually vertical wire antennas with a single long horizontal wire that functions as a cap hat and does very little radiating.

 

[MrSuburban]

76Q, here are some variations for radiator and top hat lengths for a 1/4 wave radiator. I used slanted down radials and one model that is full length and slanted down radials, and one model that is full 1/4 wavelength using 4 x 108" horizontal ss radials.

I also have a model of a simulated mobile, but I don't think the pattern is near what you might expect, so I didn't include it. I'm not even sure it is a good model. It shows to be workable however. I used the 4 horizontal radials and made 2 x 6" x 4' and 2 x 6" x 8'. I will work with it a bit and if it looks promising, I post it later. This may prove to be futile however, because mobiles have a very unpredictable ground plan with variations and curves that are irregular and may be difficult for me to model.

The numbers at the end of the captions are the length in inches for the radiator and the top hat including a little space for the feed point hub.

View attachment 4731

Eddie you have more segments in the cap hat than you do in the verical radiator. Try adding a bunch more segments in the vertical radiator

 

[MrSuburban]

anybody ever seen a top-hat on a commercial television or radio broadcasting antenna ?
i haven't , but i'm guessing the station and their advertisers want to reach every potential customer . if a top-hat will increased their broadcasting range or decrease the wind load and keep the same performance why wouldn't they use them ?

Yes they are common because they are using shortened verticals

 

[BOOTY MONSTER]

first time i ever read/herd that cap hats only effect the rx and not the tx .

so cap'in kilo , in your use it was jut to shorten the antenna ? not for any supposed gain in tx ? from what i understand VLF , LF , HF and VHF react differently RF wise . so maybe maybe my question about commerical antennas was moot for HF/27 MHz. .
there's still a lot i don't know about antennas obviously . but as long as folks keep giving answers i'll keep having questions .

hehehe sooooo ...... is coilys audio ball a top hat or a corona ball ?

 

[Marconi]

Eddie you have more segments in the cap hat than you do in the verical radiator. Try adding a bunch more segments in the vertical radiator

MrS, I have 7 segments in both. This was just a quick and dirty type of project. I started with a near 50/50 radiator to top hat model using 7 segments each and as I change the lengths, I just left the segments alone. It will make a little difference if I fixed the segments to the minimum per wire, but I didn't see enough difference to matter.

On a casual check MrS, it just doesn't seem to matter in this case. I'll check them all out though, and if I find one that does make the pattern, angle, gain, match, SWR, or reactance show a noticeable difference, I'll fix it.

Thanks for the tip.

 

[Marconi]

first time i ever read/herd that cap hats only effect the rx and not the tx .

so cap'in kilo , in your use it was jut to shorten the antenna ? not for any supposed gain in tx ? from what i understand VLF , LF , HF and VHF react differently RF wise . so maybe maybe my question about commerical antennas was moot for HF/27 MHz. .
there's still a lot i don't know about antennas obviously . but as long as folks keep giving answers i'll keep having questions .

hehehe sooooo ...... is coilys audio ball a top hat or a corona ball ?

Being as they're rather small BM, I'd consider them mostly functional as a corona ball, a static or lightning supressor, but the main thing they do is keep folks from poking their eye.

 

[Captain Kilowatt]

first time i ever read/herd that cap hats only effect the rx and not the tx .

so cap'in kilo , in your use it was jut to shorten the antenna ? not for any supposed gain in tx ? from what i understand VLF , LF , HF and VHF react differently RF wise . so maybe maybe my question about commerical antennas was moot for HF/27 MHz. .
there's still a lot i don't know about antennas obviously . but as long as folks keep giving answers i'll keep having questions .

hehehe sooooo ...... is coilys audio ball a top hat or a corona ball ?

In my case it was not to shorten the antenna but rather because the antenna was short. A full size 1/4 wave on 1450 KHz is about 165 feet +/- so a 96 foot antenna is not much over 1/8 wavelength. At that frequency bandwidth is already hard to come by and even more so with a short antenna. Adding a cap hat allows a smaller coil at the base for matching which means lower losses and greater efficiency overall. The antenna gain persay does not increase but the efficiency does. I can't figure out what you mean when you said " from what I understand VLF , LF , HF and VHF react differently RF wise". AFAIK they all react the same regardless of frequency when it comes to antenna. The effect the ground beneath those antennas does change from VLF to VHF however,the former being extremely dependent on good ground conductivity while the latter pretty much cares less.

 

[MrSuburban]

MrS, I have 7 segments in both. This was just a quick and dirty type of project. I started with a near 50/50 radiator to top hat model using 7 segments each and as I change the lengths, I just left the segments alone. It will make a little difference if I fixed the segments to the minimum per wire, but I didn't see enough difference to matter.

On a casual check MrS, it just doesn't seem to matter in this case. I'll check them all out though, and if I find one that does make the pattern, angle, gain, match, SWR, or reactance show a noticeable difference, I'll fix it.

Thanks for the tip.

I wouldnt add the minimum I would add more you will get a more accurate model i would beleive.

 

[Captain Kilowatt]

I am developing a cap hat and may have it done by the end of the day. This will have an added feature of adjustability on the level of audio. Promise to make a world premiere here! The proof will be in the pudding. You will have no doubt in your mind that this can actually be done for sure.

Someone else needs to study a bit more on antenna and RF theory. A cap hat will not, in no way, ain't-going-to-happen-bullshit-if-it-is-claimed otherwise, going to effect the audio level of a transmitted or received signal. All the commercial broadcasters know that. All the RF engineers know that yet for some reason CB antenna manufacturers seem to know otherwise. Must be something real special about that Bubba's School of CB Tuning and Antenna making.

 

[AudioShockwav]

Good debate going on, just keep it on track and the comments tactful

tactful - having or showing a sense of what is fitting and considerate in dealing with others

tactful - showing skill and sensitivity in dealing with people

Thread Cleaned and re-opened
please stick to Hamers posted suggestion
( quoted above)


73
Jeff

 

[nfsus]

I built an astroplane antenna without a tophat. Legenthed the element to get away from the hat. Its noisier than my factory ap. The only change was what i said. So does the hat quieten the recieve? I have 2 s units more static.

 

[AudioShockwav]

I built an astroplane antenna without a tophat. Legenthed the element to get away from the hat. Its noisier than my factory ap. The only change was what i said. So does the hat quieten the recieve? I have 2 s units more static.

Can you post some pictures and measurements of your home brew AP?
Thanks.

73
Jeff