Capacitance Hat's Don't add Audio  6Likes
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05-22-2011, 12:40 PM
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Originally Posted by 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. 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
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05-22-2011, 12:41 PM
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Quote:
Originally Posted by 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 ? | Yes they are common because they are using shortened verticals
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05-22-2011, 12:48 PM
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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 ? 
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05-22-2011, 01:13 PM
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Originally Posted by MrSuburban 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's YouTube Channel We're just lucky that Mother Nature doesn't require our antenna systems to be perfect in order to work our radio.
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05-22-2011, 01:20 PM
| | Supporting Member | | Join Date: Oct 2005 Location: Houston & Corpus Christi
Posts: 3,282
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Quote:
Originally Posted by 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 ? | 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.
__________________ Marconi's YouTube Channel We're just lucky that Mother Nature doesn't require our antenna systems to be perfect in order to work our radio.
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05-22-2011, 02:33 PM
|  | Professional Amateur | | Join Date: Apr 2005 Location: Nova Scotia,Canada
Posts: 8,660
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Quote:
Originally Posted by 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 ? | 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.
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05-22-2011, 11:06 PM
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Quote:
Originally Posted by Marconi 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.
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03-11-2012, 03:04 PM
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Quote:
Originally Posted by BDOG-T7 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. 
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Last edited by AudioShockwav; 03-11-2012 at 04:33 PM.
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