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Hobbyists Create GPLed DIY Super TV Antenna
Freshly Exhumed writes "Retired and hobbyist antenna engineers working together in the Digital Home forums have taken an obscure 1950s UHF TV antenna called the Hoverman [PDF] and subjected the design to modern software-based computer modeling in hopes of optimizing its middling performance. The result: the new Gray-Hoverman antenna is more powerful than similar commercially manufactured consumer antennas in every category, sometimes by whopping amounts. Best thing yet: they've released the design, diagrams, and schematics under the GPLv3 so that we can roll our own! Quoth one of the testers, a former U.S. Government antenna engineer: 'Boy, this antenna is hot... This antenna is a vast, and I mean REALLY VAST improvement over anything I have used.' The home thread of the Gray-Hoverman development gives the background of their great work."
I've been out of the amateur radio hobby for nearly a decade, but I seem to remember issues of the ARRL Handbook dedicating plenty of space to antenna design. What is this guy's original achievement?
Just a few years ago I thought broadcast TV and "rabbit ears" were pretty much gone forever. Now, broadcast TV is often the best quality high-def signal available. What makes broadcast relevant again is having the Internet to compliment it. With cable TV you get something like 120 channels, which is both too many to flip through, yet not enough to get whatever you want whenever you want it. I think a great combination in the future will be Broadcast TV for shows with huge audiences (like football and network news) plus Internet for pre-recorded stuff people want on demand.
The main reason the original Hoverman died out was that the bandwidth was not enough to cover the UHF (Ch 14-83) spectrum. This new variant appears to mainly improve on it by shifting its limited bandwidth down. The difference nowadays is that with the 700 and 800 Mhz bands removed from the spectrum used for TV, the basic Hoverman design DOES have the bandwidth to cover it, at least starting next year for "in-core" channels in the US.
Maybe they should do some software-based computer modeling of their webserver...
What doesn't kill you only delays the inevitable
Fifty-seven channels and nothin' on.
"Chinese Amazons, power armor, laser swords.... things just meant to be." - Shampoo, A Very Scary Bet
I don't know what a "U.S. Government antenna engineer" is - but I want that job!
---- "Logoff! That cookie shit makes me nervous!" - A. Soprano
I may be totally off on this, but wasn't the FCC going parcel up and see the bandwidth that UHF uses? Or have they already? If so, what use is this? Forgive me for being potentially totally out of it, but it is Friday...
Slashdot: all your pointless conjecture are belong to us!
I will be living in a new duplex soon in Bloomington, IN where I can receive the nearby PBS station, WTIU quite easily, but apart from that the nearest stations are all serving Indianapolis. That's around 50 miles away, so I am wondering if an antenna like this would make it possible to receive several more stations. Keep in mind that I need reception to be very good or excellent...we a matter of months away from the analogue switch-off now.
I have seen various antennas capable of pulling stations from a good distance away, maybe 20 miles or more, but depending on weather and other factors they can come in pretty fuzzy. When NTSC's gone I want a solution that will work. Has anyone here played with antennas like these? I couldn't really find anything that gave the approximate range on the site.
Take off every sig. For great justice.
What's wrong with this article? It starts off boasting about the new antenna, then wastes your time telling you the history of the old antenna and its designer, like it wants to be some kind of man page.
You have to go to a second page--which isn't responding--to get to the real story.
Authors who write this way do a disservice to their readers, and generally the history they've written is no more than platitudes and puffery.
If your article is about a new device, get on with it, and leave the phony history rewrite to the mooks at wiki.
The server is Slashdotted, so I can't find out what legal protection this new antenna has. I hope it has some protection against cheap knockoffs. Most people aren't going to want to build this themselves, and will want to buy a factory-made version.
The Hoverman-Gray is described as "GPLed". If that's the only legal protection it has, then I predict a lot of cheap knockoffs that don't work very well. Some trademark protection (with free licenses for anybody who agrees to follow the spec) would be nice.
Wow, this new concept of wireless TV might just take off!
...but this is obviously impossible. Nobody creates something new, then gives it away for free, that's why we need copyrights.
Or could that tired old argument just possibly be wrong?
No tyrant thrives when every subject says no.
Seriously, geeks will be geeks and find something to homebrew... But what's next? An open source buggy whip? A Franklin stove built using a Beowulf cluster of Commodore 64's to optimize the burning and thermodynamic characteristics?
In an age of cable and satellite everything, it's often assumed that antennas are a thing of the past, or are limited to cheap Chinese rabbit ears.
Think again. While living in Appalachian Kentucky we found that the Radio Shack FM antenna on the roof did an amazing job of pulling in radio stations. Some times the old tech is the best tech.
Three Squirrels
I have trouble seeing why this is so important. Of course, since the site is slashdotted, I can't find out any gain numbers. This business of experimenting with antennas is very old hat, as is NEC.
Paul Anderson
"I drank WHAT?!" -- Socrates
Performance and Designs, Schematics, and Diagrams to follow as they become available.
Gray-Hoverman Antenna | Performance | Designs, Schematics, And Diagrams | Join the Digital Forum Discussion
The Gray-Hoverman Antenna For UHF Television Reception
March 13, 2008
This project is dedicated to Doyt R. Hoverman (b.1913), the man who created and did the early work on the Hoverman antenna at a time when antenna modeling programs did not exist. His work would have been entirely created and improved by field testing, trial and error, and with a great amount of calculation without the benefit of electronic devices. Without his efforts, our work would not have been. Doyt Hoverman passed away in December, 1989 at Van Wert, Ohio, USA.
First, A Bit About The Original Hoverman Antenna
Doyt R. Hoverman's original design for a television antenna was granted US patents #2918672 on 22 Dec 1959 and #3148371 on 8 Sept 1964, which expired in 1979 and 1984 respectively. To view them, click on this link and then simply enter the patent number mentioned above to retrieve each.
In his patent applications, Hoverman describes two designs with 4 rod reflectors, full wavelength and co-linear half-wavelength reflectors, with the second design using the following specifications:
* Driven array = 56" dual segments with 8 subsections of 7" (same as the first design)
* Reflector spacing = 3.5"
* Full Wavelength Reflectors:
o Top and bottom = 29"
o The two middle = 24"
* Half Wavelength Co-Linear Reflectors
o Top and bottom = 14"
o The two middle = 10"
The above dimensions are for reception of UHF channels ranging from 14 to 35, as claimed in the patent. He gives design equations for shifting the range, and suggests 35-58 and 58-83, although the range 58-83 is not applicable now as UHF TV channels in North America only go to 69, and after 2009 will only go to 51.
The original Hoverman antenna design did not have a reflector and used a driven array of 56" segments with eight zig-zag 7" sub-elements. The original patent # 2918672 claimed UHF and VHF reception. The modeling results did not find any positive net gain for VHF Low channels 2-6 nor for VHF High channels 7-13.
There is very little information available anywhere on the Hoverman antenna. The only reference to any commercially manufactured Hoverman antennas seems to be in the article (PDF) The Hoverman, VUD Sept 1982, which mentioned a 4 bay Hoverman made by AntennaCraft named the model G-1483 and which was also made for Radio Shack as the model 15-1627, seen in this photo courtesy of tvlurker:
Radio Shack Hoverman
Some of these commercially manufactured Hoverman variants used 7 pairs of collinear rod reflectors. Judging from the AntennaCraft and Radio Shack websites and many Internet searches those Hoverman models do not seem to be currently in manufacture, although it seems that old stock of the AntennaCraft Super-G 1483 is or was available from SummitSource.com.
Recent Research On The Hoverman
Canadian antenna buff Autofils, speculating in an online discussion of Build It Yourself Antennas on the Digital Home web site in early 2008 on the possibility of experimenting with the old Hoverman Antenna design, sought out old sparks, another Canadian antenna enthusiast, who used 4NEC2 computer antenna modelling software to model the original Hoverman design. His research showed that the Hoverman had p
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Yes, no one uses antennas for anything anymore~
You fail in the imagination dept.
The Kruger Dunning explains most post on
Haven't used a UHF antenna in 25 years, so the fact that anyone made one is a miracle in itself. U can make antennas more directional + high gain or less directional + lower gain, but anyone who can actually make antennas better deserves a BluRay player.
Even if someone does begin marketing these commercially, I don't see "cheap knock-offs" being a problem. It doesn't cost anything more to manufacture one of these with the correct dimensions (which is pretty much what determines its performance) than to make one with the wrong dimensions. The only thing that would likely make an antenna "cheap" in this sense is purely mechanical - inability to hold up in high winds, or to the sun's UV (I've seen some TV antennas with plastic components that were literally crumbling due to long-term UV exposure).
Check out this antenna: http://uhfhdtvantenna.blogspot.com/
It has gotten some interesting write ups and looks similar in many ways to the new hoverman.
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Please tell me how to reply to the article instead of a comment so that I bring my comments up a tier.
Thanks.
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So, what about VHF? I realize the majority of DTV broadcasts are UHF, but a few are in the VHF range. How is this antenna's performance down there?
Can you hear me now?
Sorry I couldn't resist...
Sheldon
http://www.networkmirror.com/C3MlvQvZX12kVGAy/www.digitalhome.ca/ota/superantenna/index.htm
I deny that I have not avoided attaining the opposite of that which I do not want.
So, what about VHF? I realize the majority of DTV broadcasts are UHF, but a few are in the VHF range.
Ugh, it's research time. As I understood it, all VHF is going away. There is some VHF DTV now so studios can get DTV stuff tested and ready for the transition. When the switch is flipped, the analog UHF stations will go away and the VHF DTV stations will move to UHF. Does anybody know for sure? Investing in VHF antenna stuff may be a waste of resources.
Does anyone know the plan? Will there be any VHF DTV after the analog switch-off?
The truth shall set you free!
This is a great antenna especially with the new digital TV and upper channels will be auctioned off. If you look at the gain of the antenna the upper channels don't have as good of gain as the lower channels.
Very nice work. These antenna designers have the enormous advantage of having antenna simulation software that runs on PCs. It's a problem where intuition isn't good enough, hand calculation involves oversimplification, and repeatable experimental work requires either an RF anechoic chamber or a big flat field in an RF-quiet area where you can transmit on the band in question. Antenna test ranges thus tend to be located in Outer Nowhere, and hams who do antenna development usually go to some isolated place to test. Otherwise, you can't tell if a small change made things better or worse.
How the hell do you rotate it? Those pictures looked like all the antennas were mounted on the side of a house. Also, what is its wind load if you put it up on a mast? Would it disintegrate with 60mph winds? As far as the rotation issue goes, rural people need it to orient the antenna's gain towards the station they want, and city people need to rotate it as well to get rid of ghosts caused by large buildings.
There are a number of stations broadcasting in VHF DTV presently, and there will be quite a few more post-Feb09 transition. Several VHF stations will retake their VHF frequency for DTV. The biggest reason to go to VHF is that it needs substantially less power to cover a certain number of square miles.
Very few stations, though, will be in the low-VHF ranges (channels 2-6). Ignition noise, lightning, etc, are big problems in low-VHF. Those frequencies covered a lot of ground for the watt, even with more interference in that band. But, the errors are generally too much for digital reception, so there aren't but a dozen or so low-VHF digital transmitters now. I expect that 30 MHz will eventually be repurposed.
But, high-VHF (RF channels 7-13) is probably with us for quite a while.
Modern model-based antenna design is a lot different and a lot more challenging. For example, building a 5-band antenna for a cell phone defies straight forward dipole etc design. People are increasingly doing very different stuff. For example, the guys over at http://www.physics.otago.ac.nz/ are using genetic algorithms linked with an electromagnetic modelling package to design antennas. Some of the shapes look pretty wierd.
Engineering is the art of compromise.
Hmmm... one side effect, then, may be that a lot of marginal reception areas will be SOL entirely. (I've lived in places that could get low-channel VHF -- from 100 miles away -- but nothing else.)
~REZ~ #43301. Who'd fake being me anyway?
up high in the clear with a good low-loss feedline. When I was a kid, we lived in the sticks. The nearest UHF channel was about 35 miles away. We got good reception from that as well as two stations that were about 50 miles away by having a 4 element bowtie antenna that was on a 30 foot guyed mast on top of a two story house. I figure 60 feet up. That was back in the days when the TVs used tubes!
Try not to use the cheap old flat 300 ohm twinlead. It's pretty lossy at UHF frequencies. If you can get foam filled twinlead, that's better. I see that Radio Shack 15-1175 is foam filled and is under $20 for 100 feet.
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain
Tm
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Maybe you've noticed that over the air TV broadcasts are essentially coming to an end in a few years?
Or maybe you're too stupid to realize that performing extreme optimizations on one specific antenna design means jack point shit for other antennas?
My current antenna stinks, and since there's fears of a recession, I sure as heck won't plunk down for a dish right now :->
Stating on Slashdot that I like cheese since 1997.
Comment removed based on user account deletion
Actually, I've noticed exactly the opposite.
* Many more homes will be able to receive an OTA signal, that previously could not.
* Digital broadcasts will offer perfect reception, eliminating much of the need for cable/sat.
* OTA HDTV will offer the highest quality picture anyone can get.
* OTA ATSC offers the potential for more TV channels than an expensive subscription service (50*6 = 300), in addition to other informational services.
* Rising prices and horrendous support will push people away from cable/satellite.
* Proprietary STBs and feet-dragging on CableCard will push even more people away from cable/sat.
* DVR technology will eliminate the need for syndication, and there the business model for 90% of cable/satellite networks will fail.
* The quality of original programming on cable/satellite networks has dropped SEVERELY, anyhow.
* Pop-up ads on cable/sat networks (largely not found on broadcast) will push even more people away.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
You are mistaken.
Check my journal entry for everything you might want to know. Specifically, you can follow the FCC link at the end for proof that VHF-high (7-13) is most certainly NOT going away. http://hardware.slashdot.org/~evilviper/journal/184757
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
once you get the set. I'm using an old school antenna for my HD. Comes in perfectly. SD for $45 per month via satellite takes care of the "cable channels". To do the same by Cablevision....$85 per month, or by satellite, also $85 per month plus taxes. So, in one year, I would have $400, which is a lot more than my $90 of Radio shack antenna and some coax cable. (btw, as a Ham, I say avoid rat shack coax at all opportunities-Belden, Winegard, etc are much much better). You can spend a lot more for the same thing. Dishnet looks OK for the more popular channels, where compression is less, but for kid TV, you can see every artifact. You don't need to be anal-retentive about the design and the wires. Since you are not transmitting, close enough is good enough, and if it does not work, you won't break anything. Chances are, if you are even close, it will work, and well.
No, it is nothing like a DB4. It is superior to 4-Bay Bowtie Reflector Antennas as you can see by the comparisions with the Channel Master 4221, which is considered the cream of that crop. Go ahead and build which ever antenna you like, but the Gray-Hoverman is more powerful so why waste your time on other designs?
I deny that I have not avoided attaining the opposite of that which I do not want.
The * is that indoor antennas have a lot of variables driving reception quality.
Verizon: Latin for "poor rural service".
Wow, you're quite the dumbass.
Analog broadcast TV is being ended.
This Antenna specifically addresses Digital TV reception, which is what analog is ending in favor of.
Why was parent modded down? It is the most informative post I've seen yet in this discussion.
Why did you mention 30MHz? Channel 2 in the US starts at 54 MHz, right? 30MHz is just above the amateur radio 10m band (ends at 29.7 MHz). Between 30MHz and 50MHz is a no-mans-land of 'stuff' including ancient cordless phones and baby monitors, fixed, mobile, land mobile, an ISM band, and even a little radio astronomy. 50MHz is the beginning of the amateur radio 6m band that extends right up against channel 2 at 54 MHz. If channel 2 goes away, I'll be tickled - no more RFI to channel 2 from 6m operations.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
I was suggesting the 30 MHz range from 54-88 MHz (minus the 72-76 that is not a TV allocation) will probably be assigned to something other than TV at some point. It was a very good place for NTSC signals, but is not turning out to be a good band for ATSC.
I know of a few amateur radio guys that wouldn't mind having it for a big ATM-style data channel. (Me, me!!!)
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.