Eureka

I finally went by to take a picture of that antique antenna, but the tree foilage was so thick, I couldn't get a good shot. Here's a screengrab off of google earth, which was taken in winter time:

Not sure if it's the same antenna as the popular science tripole, but it's a biggun!

Piggie

The original 4228 for Low and High VHF.

This absolutely proves my point. They knew how to build antennas, and in some cases better in the past. It seems a year ago or so there was a push again by home builders to make a HighBand VHF bowtie. While the one in the picture above is a folded dipole in front of a screen, still the "new" version was crossed whiskers in front of a screen.

Or we can look at the AntennasDirect C5 Antennas Direct | C5 ClearStream VHF HDTV Antenna for Digital Television DTV All we have here is a quad loop in front of a screen.

Between the now personally claimed "original" above and the other two, the only difference is the driven element. And all those driven elements are decades old in design.

The only new antenna design I have seen in my life are fractal antennas and I am still trying to figure out how they work. The only ones that really understand them can't seem to simplify the finding enough for me to understand them, though I am slowly getting the idea what they are doing.

In a sense or maybe actually, the Gray-Hoverman is fractal with only one iteration?

Eureka

The antenna I posted in post 21 above has a screen but no bowties.

Eureka

From the AD web site:
"the ClearStream 5’s efficient, compact design offers excellent gain and impedance matching across the whole post 2009 VHF DTV spectrum"

The post 2009 VHF DTV spectrum is the same as it was pre-2009; channels 2 thru 13, not 7 thru 13. Somebody needs to stop these people from their blatant lies.

EscapeVelocity

Thanks for the Google Spy pic, although its a bit difficult to see. Maybe you could snap a pic during the winter when the leave clear, a little better than googles.

Piggie

The C5 is a VHF, so now they are lying about their VHF picking up UHF also. Double lie we caught them in between us, from their one sentence. Let them talk much and it pours like thick syrup.

C5 would make an easy basketball hoop if you turned the loop sideways.
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That is why I wasn't afraid to use their name in the other thread. They do more harm to the cause of OTA.

Good case in point just happened in the Gainesville, FL just in the last day. So it's not hype or our attitude, but really confuses people.

They go to the store, because C4's are mass produced in China for nothing sold here more than real well made American antennas.

The box HD Ready not UHF antenna. They get home, frustrated. Figure how few people in the public read or post here and how many probably bought their misguided marketing hype crap and just figured they could not get reception.

Here you go, perfect example. Just yesterday.

http://www.avsforum.com/avs-vb/showt...8#post17127528

Piggie

Eureka if you have never read this it's well worth 10 minutes to read this thread.

Ken Nist. whose name on that forum is his ham radio call kq6qv

He gets into with the owner of AntennaDirect.

HDTV Magazine - HDTV Forum - View topic - Antennas Direct's Clearstream2 Antenna Available for Pre-Order

Plus I guess you know if you google map their address it's a storage shed.

flcs3

The Hoverman is a variation on the Chireix, where the last segment of each doublet arm is turned outward horizontally rather than inward diagonally. It is also driven for horizontal polarization (the only Chireix designs that I have seen so far have been veritcally polarized). Each of the diagonal segments best radiates with a half-wavelength, and the 90 degree bends mitigate the interferrence caused by the current reversals that occur at higher harmonics on linear dipoles. Unfortunately, the basic Hoverman geometry shows poor VHF VSWR, even when the total length of each arm is properly tuned, but this can be improved with the use of open sleeve resonators (Cebik actually calls them parasitically driven elements) and tuned reflectors. The same remedies work to improve the bandwidth over that of the basic dipole, as does varying the length of the individual segments on the UHF band. Otherwise, you can make a gross estimate of gain by counting the effective half-wavelenth segments as dipole radiators (~2dBi), i.e. 4 at VHF (<+6dB) and 12 to 16 at UHF (<+10-12dB).

So, I think of the Chireix and Hoverman as something akin to a Franklin array, as a way to configure a dipole array with directly connected dipoles rather than using separate feed lines. Perhaps mistakingly, I think of (most) fractal antennas as dimensional compressions of existing designs, which hurt performance while helping it fit a particular application. However, I haven't been looking for their applications for multi-band harmonic operation, either.

BTW, in post 2 one of the pictures shows a trapper antenna, where folded dipoles are used in place of stubs connecting the Franklin array dipoles.

The Chireix is best known for shortwave use in the Chireix-Mesny curtain, which dates back to the 1920s (roughly contemporaneous with the development of the Yagi-Uda). Although Chireix was awarded many patents, mostly for RF amplifier designs, I haven't found one for this antenna. RCA Review had an early description in English, about 1928. Hoverman had US Patents issued in 1959 and 1964. The Trapper patent was awarded in 1955 and assigned to TACO.

Piggie

Great information. One of the things both GH and Fractals have in common is the antenna elements themselves become the feed line for the parts of the antenna farther away from the feed point. This is where I came up with the concept of the GH being just the first iteration which in any fractal doesn't even look like a fractal.

Just a though. Same idea, neither antenna need internal feedlines, as their elements also serve this purpose.

But then again, a folded dipole acts as an antenna and transmission line at the same time. How it ends up matching at 300 ohms (over simplified). So actually a folded dipole is in no way a fractal and uses itself as feedline between it's two elements.

Eureka

I've read the Ken Nist discussion and have seen the AD "storage building" in the past.

I like your posts on avs. Hope they don't get pulled.