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Hobbyists Create GPLed DIY Super TV Antenna

ScuttleMonkey posted more than 6 years ago | from the what-open-source-can-do dept.

Hardware Hacking 185

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? (1)

CRCulver (715279) | more than 6 years ago | (#22755102)

I've been out of the amateur radio hobby for nearly a decade, but I seem to remember issues of the ARRL Handbook [amazon.com] dedicating plenty of space to antenna design. What is this guy's original achievement?

Re:How is this different than what hams have done? (5, Insightful)

Anonymous Coward | more than 6 years ago | (#22755222)

This is a specific variation of the Hoverman antenna. The first original achievement is the specific design, which would be enough justification for an article on its own. I'm not an expert on the history of antenna design so I can't vouch for that.

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?

Re:How is this different than what hams have done? (-1, Offtopic)

notque (636838) | more than 6 years ago | (#22755402)

Off Topic, but..

Bertrand Russell is my favorite writer. Weird to see him quoted here in this context, but quite accurate of a statement in my mind.

Re:How is this different than what hams have done? (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#22755462)


North Vietnam should have NOT realeased to further U.S. democracy.

Kilgore Trout

Re:How is this different than what hams have done? (0)

Anonymous Coward | more than 6 years ago | (#22755596)

In Sweden, where i live, everyone has digi-tv antenna's *exactly* like the ones depicted in the pictures on the linked pages (the flat wiremesh ones), in Denmark, which is real close, noone has these antenna's !... weird isn't it...

Renewed niche for broadcast TV? (5, Interesting)

timeOday (582209) | more than 6 years ago | (#22755130)

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.

Re:Renewed niche for broadcast TV? (5, Funny)

noidentity (188756) | more than 6 years ago | (#22755546)

What makes broadcast relevant again is having the Internet to compliment it.

The Internet loves to compliment things. Why yesterday, it was complimenting me on how well I was using its bandwidth.

Re:Renewed niche for broadcast TV? (0)

Anonymous Coward | more than 6 years ago | (#22756078)

Nice post. Thank you!

-- The Tubes

Re:Renewed niche for broadcast TV? (4, Interesting)

darjen (879890) | more than 6 years ago | (#22755620)

Personally, I don't even bother paying for cable TV anymore. I have an early gen hdtv (at least 3 years old) that I use with a cheapo Radio Shack HD antenna. Gets me all the local HD channels. Before that I was paying an arm and a leg for HDTV from Time Warner. I also downgraded my internet to first tier, so now I pay only $15/month for that. Huge difference and great pictures. If I really want to watch something I can download it, but usually Netflix fills the gap for me. The time you speak of in the future is pretty much here for me.

Re:Renewed niche for broadcast TV? (0)

Anonymous Coward | more than 6 years ago | (#22755800)

I can only agree with you, and have been doing this for the last 2 years or so. What made me change is mostly moving back to Canada after a few years in the US. Many of my favorite shows where not available anymore. Other shows that used to be on a single channel (Survivor followed by CSI) are at the same time on different channels here. Since a reality show is boring on re-runs, I watch survivor and download CSI once the season is over.
I recently abandoned Cable, I keep it only for Internet connection (faster dans DSL in my area). Without cable TV I don't even get 24, Sci-Fi shows, and many others. When a season is over I hit the Web.

I hope the "Powers of the market" will realize this is a great niche. Internet connection is very hight here (I'm at 80$/mo for 7Mb-up/80Kps-down/Unlimited (hard to share FTP with friends). This is about double the price of "Basic cable" with all my regular shows, so no guilt here either, the same business gets the same $$ from me. or more.

How do I reply to the article itself? (1)

Lorien_the_first_one (1178397) | more than 6 years ago | (#22756006)

Hi,

I just want to say that I'm really starting to enjoy /. The best part is the good news, the news about people doing things that make the world a better place to live. To me that's a rare find.

Please tell me how to reply to the article instead of a comment so that I bring my comments up a tier.

Thanks.

Re:How do I reply to the article itself? (1, Offtopic)

bkaul01 (619795) | more than 6 years ago | (#22756092)

Scroll down to the bottom of the page and click "Reply" there, rather than at the bottom of a user's post.

Re:How do I reply to the article itself? (1, Offtopic)

h3llfish (663057) | more than 6 years ago | (#22756112)

Normally, this is where I'd call you a dumbass, because I'm a jerk. But, I puzzled about this at first too. So, since we're both dumbasses, I figure I should help you out.

What you wanna do is click the "reply" button at the top of the comments page (towards the right), above any of the comments, rather than the "reply to" link that you clicked to post this current comment. It's not actually the most intuitive UI ever designed.

Re:How do I reply to the article itself? (1, Offtopic)

baldass_newbie (136609) | more than 6 years ago | (#22756676)

Please tell me how to reply to the article instead of a comment so that I bring my comments up a tier.

You are so obviously new here (if not a troll) but I have to tell you...only the first guy in gets to post to the story. After that you're on your own.

Bandwidth (5, Informative)

russotto (537200) | more than 6 years ago | (#22755140)

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.

Re:Bandwidth (1)

Freshly Exhumed (105597) | more than 6 years ago | (#22755188)

That's what is on the new antenna's web site, but thanks for clarifying it further.

Re:Bandwidth (3, Interesting)

russotto (537200) | more than 6 years ago | (#22755272)

Gotta cater to the masses who aren't going to RTFA anyway :-). I remember some excitement about the design over on the lumenlab antenna thread; I don't know if these are the same guys. I do wonder, though, if a 4-bay bowtie might still be king if you just widened it a bit to move the peak down some. The Gray-Hoverman design is probably easier for the DIYer to fabricate, as it avoids the crossed phasing lines the 4-bay bowtie has.

Re:Bandwidth (2, Interesting)

Freshly Exhumed (105597) | more than 6 years ago | (#22755372)

The lumenlab antenna forum is unrelated, but they do offer DIY plans for other types (4-bay bowtie reflectors).

Modeling the conventional 4-bay bowtie reflector didn't yield the kind of huge jump in performance that the Hoverman did.

Re:Bandwidth (2, Interesting)

Babu 'God' Hoover (1213422) | more than 6 years ago | (#22756786)


That the modeled hoverman looks better than the modeled conventional bowtie does not necessarily translate to the physically built antennas. This is why we still have and use antenna ranges.

Don't really need the RF bandwidth but a wifi version would be fun to build and because of the bandwidth, the tolerances won't be too severe.

30"x 40" would scale down to 8"x10" and have 14dbi(modeled) gain.

Re:Bandwidth (5, Funny)

More_Cowbell (957742) | more than 6 years ago | (#22755232)

the basic Hoverman design DOES have the bandwidth to cover it
However, the server TFA is on does NOT have the bandwidth to cover slashdot.

Looks similar to this HDTV Coat hanger antenna (2, Informative)

jerryasher (151512) | more than 6 years ago | (#22755958)

Check out this antenna: http://uhfhdtvantenna.blogspot.com/ [blogspot.com]

It has gotten some interesting write ups and looks similar in many ways to the new hoverman.

model a better server (5, Funny)

SoupGuru (723634) | more than 6 years ago | (#22755142)

Maybe they should do some software-based computer modeling of their webserver...

Re:model a better server (1)

RotateLeftByte (797477) | more than 6 years ago | (#22755186)

Nah. Thats the normal /. Standing Wave coming into play.
It sweeps all in its path like a Tsunami.
Then after a period of total anihilation,
things start recovering.

Sounds Familiar eh?

Re:model a better server (1)

Anpheus (908711) | more than 6 years ago | (#22755440)

Between your odd sentence structure and capitalization, I would like to remind you that when you say things like "sounds familiar, eh?" you should probably keep the reference you're making vague, subtle, clever, witty, or ironic. Not blatantly obvious.

Because saying "sounds familiar" after using the word tsunami makes it a little obvious.

Also, I think standing wave doesn't mean what you think it means.

Re:model a better server (0)

Anonymous Coward | more than 6 years ago | (#22755724)

Until the whole web is p2p based, it's just going to hit one bottleneck after another.

http over bittorent is the future. Until we're there, well, put up a mirror and see how you like paying for that much centralized bandwidth.

~ethana2

but... (1)

Shadowruni (929010) | more than 6 years ago | (#22755158)

From the look on your face I see you're just about gone....

Fifty-seven channels and nothin' on.

/obscure?

// oh wait this isn't Fark.com [fark.com]

//slashies!!!

I want that job! (1)

bizitch (546406) | more than 6 years ago | (#22755162)

I don't know what a "U.S. Government antenna engineer" is - but I want that job!

Re:I want that job! (4, Funny)

jd (1658) | more than 6 years ago | (#22755300)

For years, the aliens that land in Area 51 have had to make do with cheap, low-grade bobble antennae sticking out of their heads, which is very disconcerting when they run for Congress. The job of a Government antenna engineer is to design antenna that better blend in with the Congressmen's hairstyles, pointed ears, etc. This is why you don't see them any more.

Re:I want that job! (2, Funny)

mustafap (452510) | more than 6 years ago | (#22755456)

You've been watching the teletubbies, haven't you :o)

Re:I want that job! (1)

Opportunist (166417) | more than 6 years ago | (#22756732)

I bet when congressmen had some TVs in their bellies, more people would watch their speeches.

Re:I want that job! (1)

Stranger4U (153613) | more than 6 years ago | (#22755472)

I was essentially a Gov't Antenna Engineer for ~2.5 years. It isn't everything it's cut out to be. You do learn all the interesting uses that antennas are put to and the wide variety out there.

UHF going away? (1)

jwink (895907) | more than 6 years ago | (#22755170)

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...

Re:UHF going away? (3, Informative)

GiMP (10923) | more than 6 years ago | (#22755262)

They are auctioning off the frequencies used by 18 UTF channels, leaving 38. Most HDTV programming is delivered by UTF.

Re:UHF going away? (4, Informative)

Megane (129182) | more than 6 years ago | (#22756164)

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.

Re:UHF going away? (2, Informative)

Megane (129182) | more than 6 years ago | (#22756292)

Oops, I forgot about the "UHF taboo" limitations of channels n+14 and n+15 (and sometimes n-7), due to the way UHF tuners usually do IF. Apparently those are still a problem with ATSC, but less so than with NTSC.

Re:UHF going away? (0)

Anonymous Coward | more than 6 years ago | (#22755356)

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.
Actually, it's almost the exact opposite. :-) Most broadcasters are choosing to move to UHF for their digital transmissions following the transition, since for various reasons UHF works better. Some stations will continue to use the VHF band, but they'll be a very small minority.

What the FCC is doing is selling off some channels from the top end of the UHF band. Because digital channels have less crosstalk, the same number of stations can fit into a smaller number of channels. Therefore, the extra channels will no longer be needed following the cut-off in February 2009.

on that topic... (2, Interesting)

eobanb (823187) | more than 6 years ago | (#22755176)

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.

Re:on that topic... (1)

CRCulver (715279) | more than 6 years ago | (#22755236)

Why not just download whatever you want to watch? Granted, I watch little television (usually just "Human Giant", "Lost" and "Prison Break"), but I can generally get a torrent for them from Mininova or The Pirate Bay. Maybe we should rejoice that with the Internet people are no longer slaves to the idiot box, and while we all want some mindless entertainment TV isn't worth going through too much effort for.

Re:on that topic... (4, Insightful)

Chris Pimlott (16212) | more than 6 years ago | (#22756508)

Why not just download whatever you want to watch? Granted, I watch little television (usually just "Human Giant", "Lost" and "Prison Break"), but I can generally get a torrent for them from Mininova or The Pirate Bay. Maybe we should rejoice that with the Internet people are no longer slaves to the idiot box, and while we all want some mindless entertainment TV isn't worth going through too much effort for.

Why not just download whatever you want to watch?
Well, one reason might be that it is technically illegal...

Re:on that topic... (3, Insightful)

witherstaff (713820) | more than 6 years ago | (#22756918)

Having been in the ISP field I have seen too many DMCA notices to not say - watch out for torrents. You can still get served simply because your IP is of the torrents in use.

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 /., so you should already know about the wonders of usenet...

Re:on that topic... (2, Insightful)

Hatta (162192) | more than 6 years ago | (#22755260)

The only good broadcast TV is on PBS anyway, don't worry about it.

Re:on that topic... (-1, Troll)

Anonymous Coward | more than 6 years ago | (#22755364)

Ahh yes, PBS... The home of six months each of Hispanic History month and Black History month programming squeezed around 16 hours a day of begg...errr...fund raising with the occasional National Gay Men's Chorus concerts thrown in the mix.

I stopped watching PBS when Big Bird put on his first gang bandanna and used the word 'homey.'

Re:on that topic... (1)

Anonymous Coward | more than 6 years ago | (#22755286)

The site gives two models, one gets a 50 mile range the other a 100 mile range.

Re:on that topic... (0)

cheater512 (783349) | more than 6 years ago | (#22755574)

Unfortunately, NTSC isnt going anywhere. Its just the analog transmissions which are going away.
Why you Americans dont use PAL, I'll never know. :)

Btw with digital you should get longer range and better quality.

Re:on that topic... (2, Insightful)

croddy (659025) | more than 6 years ago | (#22755708)

Now, watch what you say. Our 60 Hz CRTs may be annoying, but your 50 Hz CRTs are downright unwatchable.

Re:on that topic... (1)

richard.cs (1062366) | more than 6 years ago | (#22756068)

There is a 60 Hz variant of PAL, I believe it's used in Brazil. Oddly I find a c.r.t. monitor at 60 Hz annoying but a c.r.t. television at 50 Hz doesn't bother me. I think the TVs must use different phosphors with longer persistence. At least we don't get the 3:2 pulldown when watching movies that were shot at 24 frames per second (we just watch them 4% faster).

Re:on that topic... (1)

corsec67 (627446) | more than 6 years ago | (#22756374)

Some PAL TVs use double scan, so they flash the same frame twice, getting 100Hz, which is quite a bit better than 60Hz.
I wished I could find a double scan NTSC TV for a while, then I just got a LCD TV.

Re:on that topic... (2, Funny)

squiggleslash (241428) | more than 6 years ago | (#22756878)

So what you're saying is that 60fps is a little hard on the eyes, but 50 hurts? ;)

Re:on that topic... (2, Insightful)

tonyquan (758115) | more than 6 years ago | (#22755988)

wrong, NTSC is going away in the United States. It is being replaced by ATSC, the new digital standard.. NTSC is inherently an analog standard, there is no such thing as "digital NTSC" for broadcast.

http://en.wikipedia.org/wiki/Atsc [wikipedia.org]

"ATSC Standards document a digital television format which will replace (in the United States) the analog NTSC television system by February 17, 2009."

Re:on that topic... (0)

cheater512 (783349) | more than 6 years ago | (#22756844)

Oh thank god its going for good. ...

Hey wait a minute! That looks suspiciously like NTSC!
Its merely masquerading under a new name and supports higher resolutions!
Look it even has the ridiculously stupid 29.97 fps.

Re:on that topic... (0)

Anonymous Coward | more than 6 years ago | (#22755786)

The website (before it went down) listed these antennas as having either a 50 or 100 mile radius depending on model. You may want to go with the longer-distance model. All the Indianapolis antennas are on the North side of town: WTHR is at 96th and Ditch, and CBS and ABC at 71st street or something thereabouts. A quick measurement in Google Earth shows the distance from the red dot of Bloomington to about where the NBC antenna is to be about 55 miles.

Posted anonymously because it's not like I have karma to burn. I hope your move goes well, though.

Re:on that topic... (1)

MemoryAid (675811) | more than 6 years ago | (#22755876)

Is the independent station once broadcasting on channel 4 still in service? Their antenna tower was in Trafalgar, IN, which should be close enough to receive, given reasonable terrain.

Re:on that topic... (1)

Technician (215283) | more than 6 years ago | (#22756514)

but apart from that the nearest stations are all serving Indianapolis.

I have been using a UHF yagi for quite a while. They are broad enough to pick up the lower UHF just fine and have a narrow beamwidth. If the stations you want to pick up are all clustered on a far hilltop, I have had great luck line of sight at 85 miles. Finding a UHF only yagi is a little hard, or build your own. The ARRL Antenna handbook is a great place to start.

Here is a great article on fringe area UHF reception including some extreme stacked high gain antennas including manufacture information including model number. The antenna I am using is about 30 elements long and is from the 1970's.

http://www.geocities.com/toddemslie/UHF-TV-DX.html [geocities.com]

I think the suppliers are trying to dump their VHF/UHF/FM stock as most everything is old stock. If you are in a fringe area and most stations are distant in one direction (big city hilltop nearby) then a narrow beam high gain yagi may be what you need.

Re:on that topic... (1)

baomike (143457) | more than 6 years ago | (#22756598)

>

Chicken feed.
When we had to watch Portland (OR) channels (the only ones) we used stacked 12 element Yagis, for 100 - 120 miles.

And sometimes a fuzzy picture from KOMO in Seattle 250 miles. (the hill we were on helped a lot)

Leave it to wiki (0)

rholland356 (466635) | more than 6 years ago | (#22755178)

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.

In other news (-1, Troll)

Anonymous Coward | more than 6 years ago | (#22755214)

What's the best way to solve America's problems? A: Send every nigger swimming back to Africa with a beaner under each arm. Propz to GNAA

For non DIYers (2, Insightful)

fm6 (162816) | more than 6 years ago | (#22755244)

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.

Re:For non DIYers (1, Interesting)

Anonymous Coward | more than 6 years ago | (#22755294)

"The Gray-Hoverman antenna designs, schematics, and diagrams on this site are Copyright ©2008 and are free: you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at our option) any later version.

These designs, schematics, and diagrams are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

For your complete copy of the GNU General Public License to go along with the designs, schematics, and diagrams, see www.gnu.org/licenses/gpl.txt ."

Re:For non DIYers (1)

Nimey (114278) | more than 6 years ago | (#22755498)

RTFS, dude. It says what you want to know right in the middle.

Re:For non DIYers (2, Insightful)

fm6 (162816) | more than 6 years ago | (#22756572)

Read the post you're replying to, dude. I did notice that it was GPLed.

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.

Re:For non DIYers (-1, Troll)

Anonymous Coward | more than 6 years ago | (#22755624)

I think the whole point is that anyone can make a version, even a knockoff. Stupid american, too greedy by far.

Re:For non DIYers (1)

geekoid (135745) | more than 6 years ago | (#22755630)

If it doesn't work well, wouldn't that mean it wasn't built to the spec, and thus not be the same device?

Re:For non DIYers (1)

fm6 (162816) | more than 6 years ago | (#22756592)

Yes it does. But if the name of the device isn't protected, then there's nothing to prevent every ripoff artist from building a sub-spec device and selling it as the real thing. Since these are always cheaper, they have a way of driving the real device off the market and giving it an undeserved reputation for being a POS.

Won't be a problem (2, Informative)

pestie (141370) | more than 6 years ago | (#22755946)

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).

Re:For non DIYers (1)

Jeffrey Baker (6191) | more than 6 years ago | (#22755966)

You can't copyright a useful physical object. There is not, and has never been, copyright protection for antennas, circuits, or anything like that. The only protection available is patents.

This project has released their drawings and other artifacts under an open license. Unlike useful objects, drawings are automatically copyrighted by their creators, therefore a license is necessary to allow their full use by the community.

Re:For non DIYers (1)

shaitand (626655) | more than 6 years ago | (#22756332)

On the contrary, licenses are not required for copyrighted works. They are only required to distribute or copy them. The license is to allow us to modify, change, and redistribute the works.

They could also have rendered the works into the public domain.

Re:For non DIYers (1)

fm6 (162816) | more than 6 years ago | (#22756604)

Who said anything about a copyright?

Re:For non DIYers (1)

ortholattice (175065) | more than 6 years ago | (#22756634)

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.

I would think the whole purpose of a GPL'ed design is to encourage "cheap knockoffs" i.e. competitition, so it will be less expensive for any of us to purchase. Now, it is certainly possible for one "knockoff" to be a lower quality than another, and even fraudulently claim to be one of these antennas but actually be something else, but in the end product reviews and trusted brand names should sort it out. And the fact that the design is open should make identifying a fraudulent product claim a little easier.

Re:For non DIYers (1)

fm6 (162816) | more than 6 years ago | (#22756696)

but in the end product reviews and trusted brand names should sort it out
Right, because the big brand names never sell crap.

If anybody can sell a piece of wire and call it a "Gray-Hoverman antenna" then they'll do so. Competition is fine, but most of the big manufacturers compete on price, period. If you're not careful to restrict who can claim they're selling your invention, not only does the cheap crap own the marketplace, but it destroys the reputation for the real thing. That's why we have trademarks.

Re:For non DIYers (1)

ortholattice (175065) | more than 6 years ago | (#22756726)

One other thing I wonder about is the following. Suppose a manufacturer makes an improvement to the design. This could be anything from a way to lighten the frame with the same strength to a cheaper-to-build design for a joint. Normally such incremental improvements would either be internal trade secrets or would be patented. Would the GPLed nature of the design prevent either of these from happening, so that any such incremental improvement to the design would be have to be made public and available to all other competiting manufacturers as well?

Re:For non DIYers (2, Insightful)

Jeff DeMaagd (2015) | more than 6 years ago | (#22756896)

It seems like Creative Commons non-commercial license should have been used if protecting their design was their intent.

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 is quite likely much farther down the scale. The TV antenna boxes I've seen don't generally use the proper names of the antenna type.

Wireless TV! (4, Funny)

frieza79 (947618) | more than 6 years ago | (#22755254)

Wow, this new concept of wireless TV might just take off!

I'm sorry... (3, Funny)

cloakable (885764) | more than 6 years ago | (#22755314)

...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?

Next up: The open source buggy whip! (1)

DerekLyons (302214) | more than 6 years ago | (#22755318)

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?

Re:Next up: The open source buggy whip! (1)

driftingwalrus (203255) | more than 6 years ago | (#22755436)

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.

Re:Next up: The open source buggy whip! (1)

geekoid (135745) | more than 6 years ago | (#22755672)

Yes, no one uses antennas for anything anymore~

You fail in the imagination dept.

Retirees made this? (0)

Anonymous Coward | more than 6 years ago | (#22755388)

Hey, I guess they're right. Senior citizens, although slow and dangerous behind the wheel, can still serve a purpose.

Antennas rule (1)

rueger (210566) | more than 6 years ago | (#22755414)

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.

Re:Antennas rule (1)

dotfile (536191) | more than 6 years ago | (#22755470)

Hrmm, yes. Amazingly enough, antennas work exactly the same way today that they did before the advent of cable TV, satellite radio (which also needs an antenna, of course) and all the other modern "conveniences". Except, of course, they allow you to watch & listen to things for *free*. :)

Re:Antennas rule (1)

Bananatree3 (872975) | more than 6 years ago | (#22755830)

For FREE, now in HD :)

Re:Antennas rule (4, Insightful)

zippthorne (748122) | more than 6 years ago | (#22755832)

What's amusing, (and not in a funny-haha sense, but more in a funny-smell sense), is all the new antennas out there advertising that they're somehow "digital" antennas as if the mode affects antenna performance. I suppose they *could* be optimized for the smaller bandwidth somehow, but that's not how they're being advertised. It's not as if your 17 element beam on the roof is going to suddenly start working worse than an indoor loop-antenna.

Re:Antennas rule (2, Insightful)

Detritus (11846) | more than 6 years ago | (#22756622)

The bandwidth isn't any smaller, it's still 6 MHz. What has changed is the improved resistance to interference. That allows more stations to fit in the same band, with less spectrum wasted on protecting stations from interference.

The article (4, Informative)

davidwr (791652) | more than 6 years ago | (#22755494)

Since it's heavily slashdotted, here is The Gray-Hoverman Antenna For UHF Television Reception [digitalhome.ca] as plain text

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 poor SWR but certainly exhibited strong gain either as a bi-directional antenna or, if one were to put a reflector screen on it, as a unidirectional antenna.

With assistance, advice, and encouragement from fellow antenna enthusiasts, an ad hoc research and development team came together. Using NEC II, 4NEC2, and EZNEC computerized antenna modelling software, the original Hoverman design was reconfigured in many ways over the weeks to discover whether improvements upon it could be achieved. The R&D team included Canadians GerryB, myself as moderator (stampeder), kro, 99gecko and DjiPi, joined at the same time by Americans DogT, oneolddude as well as Keo, amongst others. Thanks to Ken Nist (kq6qv) for his antenna modeling and graphing tools and assistance.

Introducing the New Gray-Hoverman Antenna
With ongoing correspondence, design improvement, and real world testing, Autofils' resulting design has achieved an extraordinary leap in UHF Television Antenna reception performance that rivals and beats most or all of today's commercially available UHF Television antennas.

"Boy, this antenna is hot. I finally got it pointed right. After I did a search for channels, I got 23 digital channels, and this is from about 30-40 miles, over mountains. I now get all 4 digital network channels from DC, 48, 36, 39, 34 (ABC, NBC, FOX, and whatever the other one is, PBS, MHZ, and a 6 channel digi mostly religious station. I was not really interested in the analog channels, but they were the only ones I could measure with the analyzer. This antenna is a vast, and I mean REALLY VAST improvement over anything I have used." -- DogT

Today we are delighted to announce the public availability of the Gray-Hoverman UHF Television Antenna designs, schematics, and diagrams, Copyright ©2008 and licensed under the GPLv3.

The Gray-Hoverman antenna designs, schematics, and diagrams on this site are Copyright ©2008 and are free: you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at our option) any later version.

These designs, schematics, and diagrams are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

For your complete copy of the GNU General Public License to go along with the designs, schematics, and diagrams, see www.gnu.org/licenses/gpl.txt.

GPLv3
There are two Gray-Hoverman configurations:

        * Single Bay Gray-Hoverman (SBGH) for nearby to fringe reception range (approx. > 0 to 100 km or > 0 to 60 mi)
                    o Two Variants of the SBGH: with 6 Pair Collinear rod reflectors
                    o with 30 x 40 Split-Screen Reflector
        * Double Bay Gray-Hoverman (DBGH) for fringe to deepest fringe reception range (approx. 30 to > 160 km or 20 to > 100 mi)
                    o Two Variants of the DBGH: with 11 Pair Collinear rod reflectors
                    o with 30 x 75 Full-Screen Reflector

Next: Learn about the Performance of the Gray-Hoverman Antenna

Digital Home | Digital Forum | Over-the-Air (OTA) Digital Television Discussion Forum
Copyright ©2008

Re:The article (2, Informative)

davidwr (791652) | more than 6 years ago | (#22755588)

Designs, Schematics, And Diagrams
http://www.digitalhome.ca/ota/superantenna/design.htm [digitalhome.ca]

Text only, with Wikipedia Commons links to the designs but not real-world photos.

Gray-Hoverman Antenna | Performance | Designs, Schematics, And Diagrams | Join the Digital Forum Discussion

The Gray-Hoverman Antenna Designs, Schematics, And Diagrams
The Gray-Hoverman antenna designs, schematics, and diagrams on this site are Copyright ©2008 and are free: you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at our option) any later version.

These designs, schematics, and diagrams are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

For your complete copy of the GNU General Public License to go along with the designs, schematics, and diagrams, see www.gnu.org/licenses/gpl.txt.
GPLv3

            Single Bay Gray-Hoverman Diagram Original Manuscript, Copyright ©2008:
            SBGH Image:HovermanDimensions.jpg [wikimedia.org]

            Double Bay Gray-Hoverman Diagram Original Manuscript, Copyright ©2008:

            DBGH Image:HovermanDimensions-2.jpg [wikimedia.org]

Gray-Hoverman Construction Examples

            Photo of PVC-fabricated Double Bay Gray-Hoverman Designed and Built by DogT:

            DBGH Photo

            Photo of Light Weight, Flexible Single Bay Gray-Hoverman Designed and Built by Keo:

            DBGH Photo

Gray-Hoverman Antenna Introduction
Digital Home | Digital Forum | Over-the-Air (OTA) Digital Television Discussion Forum
Copyright ©2008

Re:The article (2, Interesting)

davidwr (791652) | more than 6 years ago | (#22755640)

Text of Gray-Hoverman Antenna Performance [digitalhome.ca] .

Sorry, no pictures this time. There are just too many. By tomorrow morning the site should no longer be slashdotted.

The pictures are graphs showing this gets decent performance from about channels 14-62, with very good performance at about 34-54.

Gray-Hoverman Antenna | Performance | Designs, Schematics, And Diagrams | Join the Digital Forum Discussion

Gray-Hoverman Antenna Performance
Seeing is believing, so let's examine some of the test result diagrams of Gray-Hoverman design variants, paired with similar class commercial-brand competitors for comparison. We've chosen as benchmarks the highly regarded Channel Master 4221 4-Bay Reflector UHF Antenna and its bigger sibling, the 4228 8-Bay Reflector UHF Antenna, which is generally considered to be the best commercially made consumer antenna available for reception in North America.

As has been mentioned above, the North American spectrum of UHF Television channels will span 14 through 51 in the coming years. Thus, performance on channels above 51 was not deemed to be an important focus of our research and design resources.

            Single Bay Gray-Hoverman (SBGH) vs. Channel Master 4221 4-Bay Reflector UHF Antenna:
            SBGH vs. CM4221
            SBGH vs. CM4221
            SBGH vs. CM4221
            SBGH vs. Several Commercial UHF Antennas:
            SBGH vs. CM4221
            DBGH vs. CM4228:
            DBGH vs. CM4228
            Comparative EZNEC v3 Performance Plots:
            Left to Right: Original Hoverman, SBGH, CM4221
            Comparative Performance Plots
            Comparative EZNEC v3 Polar Plots:
            Comparative Polar Plots
            Comparative Polar Plots
            Comparative Polar Plots
            Comparative Polar Plots

Next: Get the specifications for the Gray-Hoverman Antenna
Digital Home | Digital Forum | Over-the-Air (OTA) Digital Television Discussion Forum
Copyright ©2008

Re:The article (2, Insightful)

dfn_deux (535506) | more than 6 years ago | (#22755716)

What this is article is clearly missing is construction directions and a BoM to make replication of their design possible without a background in the field of antenna design/construction. While I'm sure that their design works well for them. I don't see it being very useful to the average garage tinkerer to have this GPL'd without any sort of assembly/construction guidance. For something as fiddly as an antenna things like materials, construction techniques, connector positioning and design can make something which should work great end up not living up to it's potential.

Re:The article (3, Insightful)

Bobartig (61456) | more than 6 years ago | (#22755950)

Yep. I was going to build to TONIGHT. I have to the tools, and I'm good with DIY projects and tinkering, but I don't know much about antennas. I don't know what metal to use for this, or how this connects to a piece of coax to plug into a tuner. It looks extremely simple, but some critical pieces are missing.

Re:The article (3, Informative)

phil reed (626) | more than 6 years ago | (#22756476)

Pretty much any stiff metal rod or wire will work for the elements. Use whatever's handy. Any metallic screen material will work for the backplane; try window screen or chickenwire. You connect to the center points with 300 ohm twinlead TV wire, then use a standard antenna-to-coax converter (both available at RatShack).

Re:The article (1)

rboatright (629657) | more than 6 years ago | (#22756528)

the article has a detailed measured drawing with every possible detail in mm.

the bill of materials, if you use rod reflectors is "Some thick wire" Coathangers will do, copper or aluminum wire will be better. The original article shows two examples, one spaced out with pvc pipe, the other with multi-stranded cheap copper wire..

Reallly, if you visit the original article, everything you could need to know is on there, I freely admit you have to infer that you're going to use some sort of WIRE, and that the type is irrelevant (from the photos of the included examples.)

Really, you could make this by dissassembling 5 feet of cat5 and using some cardboard spacers. Building antennas isn't that hard.

Re:The article (2, Interesting)

dfn_deux (535506) | more than 6 years ago | (#22756832)

I did read the article AND I disagree with your assessment. It is not obvious that the material of the thing is unimportant, it cannot be determined weather the gauge or cross-sectional shape of the material used is of import. It doesn't specify whether soldering vs. crimping connection will have an impact on the performance nor whether the length of the lead from the connector will affect the signal received. I know that all these things matter as I have dabbled briefly in CB radio "tweaking and peaking" maybe a dozen years ago and small tweaks to the setup of a given rig could yield huge differences in the outcome. I'm not saying that reproducing what they have done is impossible, I'm just saying that reproducing their results would require better documentation and/or a greater basic knowledge of antenna design/construction than is presented on their website.

First UHF antenna in 25 years (1)

heroine (1220) | more than 6 years ago | (#22755930)

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.

Re:First UHF antenna in 25 years (1)

Detritus (11846) | more than 6 years ago | (#22756670)

You can get good gain in an omnidirectional antenna with a collinear design. The hitch is that it's vertically polarized.

VHF? (1)

bkaul01 (619795) | more than 6 years ago | (#22756126)

So, what about VHF? I realize the majority of DTV broadcasts are UHF, but a few [antennasdirect.com] are in the VHF range. How is this antenna's performance down there?

Re:VHF? DTV on VHF (2, Interesting)

Technician (215283) | more than 6 years ago | (#22756570)

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?

obligatory silly comment (1)

stokessd (89903) | more than 6 years ago | (#22756204)

Can you hear me now?

Sorry I couldn't resist...

Sheldon

This would be great. (1)

Neanderthal Ninny (1153369) | more than 6 years ago | (#22756626)

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.

It's simulation that makes it work. (1)

Animats (122034) | more than 6 years ago | (#22756714)

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.

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