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Hobbyists Create GPLed DIY Super TV Antenna
Posted by
ScuttleMonkey
on Fri Mar 14, 2008 04:33 PM
from the what-open-source-can-do dept.
from the what-open-source-can-do dept.
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."
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How is this different than what hams have done? (Score:2)
Re:How is this different than what hams have done? (Score:5, Insightful)
The second and more important achievement is that the designers tried to verify the design of this antenna analytically using relatively new methods. The computational power needed to do this didn't emerge until after this kind of small antenna was no longer in vogue. As you probably know, about half of what hams say about antennas and interference is "black magic." The kind of hands-on techie who turns into a ham tends to be more like MacGuyver and less like Bertrand Russell.
Why would the existence of antenna design as a discipline imply that no new designs are possible?
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Modelling is different tahn the old stuff. (Score:3, Interesting)
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/ [otago.ac.nz] are using genetic algorithms link
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Renewed niche for broadcast TV? (Score:5, Interesting)
Re:Renewed niche for broadcast TV? (Score:5, Funny)
The Internet loves to compliment things. Why yesterday, it was complimenting me on how well I was using its bandwidth.
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Re:Renewed niche for broadcast TV? (Score:5, Interesting)
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But, (obligatory), if you don't trust them, you can always:
1) Hit ctrl-alt-delete twice really fast and you'll unlock article-reply feature!
2) Alter windows to allow article replies by deleting C:/Windows/System32/*.dll
3) Your modem isn't fast enough. Open your computer, remove the modem, and lubricate it with vaseline to help reduce packet friction.
Bandwidth (Score:5, Informative)
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Re:Bandwidth (Score:4, Interesting)
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Modeling the conventional 4-bay bowtie reflector didn't yield the kind of huge jump in performance that the Hoverman did.
Re:Bandwidth (Score:5, Funny)
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Re:Bandwidth (Score:5, Informative)
http://www.digitalhome.ca.nyud.net:8090/ota/superantenna/ [nyud.net]
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Looks similar to this HDTV Coat hanger antenna (Score:3, Informative)
It has gotten some interesting write ups and looks similar in many ways to the new hoverman.
model a better server (Score:5, Funny)
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It sweeps all in its path like a Tsunami.
Then after a period of total anihilation,
things start recovering.
Sounds Familiar eh?
I want that job! (Score:2)
Re:I want that job! (Score:5, Funny)
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on that topic... (Score:3, Interesting)
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.
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Re:on that topic... (Score:5, Insightful)
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Well that is only partially true.
The GPs comment of:
IS an illegal method.
On the other hand, considering how fast new programming show up on iTunes and AmazonUnbox (not mentioning Hulu yet, since it isn't "Download" per se), there ARE often legal ways to down movies and television programming.
In the past when I've had my cab
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With that said, I'd suggest a good usenet service - avoid giganews - and a usenet tracker like newzbin.com. You can even SSL usenet nowadays. Safer, easier, and pretty darn easy. Of course, this is
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For non DIYers (Score:3, Insightful)
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.
Won't be a problem (Score:3, Informative)
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Suppose the hypothetical AntennaCorp(TM), who have tons of design and manufacturing experience, choose to implement this design in a commercial product. They build good gear, not the cheapest but the quality is second-to-none and they've got some patented manufacturing processes and parts like the design of their baluns and mounting hardware.
For obvious reasons, they want to protect their commercial
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As they aren't trying to sell the antenna, its plans or the knowledge, I don't know if trademarks would do any good. Even if trademarks are enforced, does it really matter? People see "TV antenna" on the box and that's all they need to know. Heck, I didn't know there were proper names for specific antenna shapes until I got interested in playing with WiFi antennas. The general public i
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GPL protects the plans. It doesn't stop me from selling old coathangers and calling them "Gray-Hoverman antennas." For that, you need trademark protection.
Wireless TV! (Score:4, Funny)
I'm sorry... (Score:3, Funny)
Or could that tired old argument just possibly be wrong?
Next up: The open source buggy whip! (Score:2)
Re:Next up: The open source buggy whip! (Score:4, Insightful)
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.
Parent
The article (Score:4, Informative)
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
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Re:The article (Score:4, Insightful)
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Re:The article (Score:4, Informative)
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Re:The article (Score:5, Interesting)
The models are obviously made with wire. You have some leeway on cross-section. Clothes-hangar wire might work :-) Solid copper somewhere between 12 and 18 gauge is easier to work and has the mechanical stiffness you will need.
Regarding your CB tweaking, there are a few things that can make a big change, but it is very easy to decieve yourself, too. Stereo tweakers are notorious for that.
Bruce
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Re:UHF going away? (Score:4, Informative)
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Re:UHF going away? (Score:5, Informative)
Actually it's 37 UHF channels, because channel 37 is reserved for radio astronomy. And 2-13 are still available, but 2-6 are not very good for ATSC. So that leaves 44-49 channels.
However, unlike NTSC, ATSC tolerates broadcasting on adjacent channels (other than the gaps at 4-5, 6-7, and 13-14), and is more tolerant of distant stations on the same channel, so it uses the spectrum more efficiently. In the past, you could have no more than 35 channels in any given market, and now you can have at least 40.
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Re:Antennas rule (Score:5, Insightful)
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Re:VHF? DTV on VHF (Score:3, Interesting)
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 D
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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 i