Author Topic: DIY HDTV Antenna  (Read 90242 times)

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Offline muldoon

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DIY HDTV Antenna
« on: November 10, 2009, 07:20:45 AM »
I thought I would post this writeup I did on making an antenna for use to pick up HDTV over the air signals out in the fringe areas.  I know plenty of people here live out in the sticks and may find this cheap DIY (and bulletproof) solution agreeable. 

After looking on the web for antennas to pick up local channels out in fringe areas I basically was discouraged to see the options available to me were all north of 100 bucks, with no guarentee they would work at the 70 mile range I needed.  I dug around a bit more and found some online plans to make clones of the more popular models, notably DB4 and DB8. 

http://www.antennasdirect.com/DB8_HD_Antenna.html


I was hoping to get some football and maybe pbs if possible.  After looking over some plans I had a plan of attack.

http://www.tvantennaplans.com/
http://www.instructables.com/id/Build-a-Large-DB8-HDTV-Antenna-Big-Bertha/
http://www.avsforum.com/avs-vb/showthread.php?p=14860111
http://forums.makezine.com/comments.php?DiscussionID=2890

It was made from an old metal discarded shelf, some coathanger wire, a splitter, some romex, a few scraps of 2x4, and 2 baluns or matching transormers.  My cost was about 9 dollars aside from what I already had on hand. 



Te test run at home in the city picked up 40+ channels, and they looked great. 



For the real test, I took it up to the country this past weekend.  It was a success. 

It was mounted in a loft, using heavy duty screweyes and a few links of adjustable chain.  The tuning and aiming was done by adjusting the large eyebolt it anchors to.  After trying many variations we found the best position was exactly the one we started with as suggested by the tvfool website and aiming directions.  Great resource if your going to do this as well, especially the google map integration that helps you understand the range of networks and what you would need to capture the signals. 



Picked up every UHF channel in a 70 mile range, giving 9 channels in HD goodness and allowing college football on Saturday and NFL football all day sunday from three different networks.  It was a thing of beauty. 





However, it does not pick up Fox out of Austin, which broadcasts on channel 7, the hi-band of VHF.  Given this is a UHF antenna (channels 14-69), this is not entirely unexpected.  I will be adding two dipole additions to this next trip up in hopes of bringing in the channel 7, and perhaps the channel 5 CW network at 103 miles out.  to be continued then ... 




Offline MountainDon

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Re: DIY HDTV Antenna
« Reply #1 on: November 10, 2009, 07:31:07 AM »
Way cool!!  Is that through an asphalt shingle roof?  My signal went south when we installed the metal roof on the house. I had to move the antenna from the attic to the roof top.


Thanks for the references.

Just because something has been done and has not failed, doesn’t mean it is good design.

Offline John Raabe

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Re: DIY HDTV Antenna
« Reply #2 on: November 10, 2009, 08:08:47 AM »
Great project!  :D :D :D Very helpful Muldoon.

I've got my old 1985 Radio Shack antenna up on the roof which catches about 80% of the stations in the Seattle/Tacoma area - except on stormy days when the signal breaks up from several stations. I'm going to dig deeper into your links and see if I can improve that.
None of us are as smart as all of us.

Offline glenn kangiser

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Re: DIY HDTV Antenna
« Reply #3 on: November 10, 2009, 06:47:23 PM »
Great and very interesting, muldoon.  If I watched TV I would try it.  I find enough TV on the computer to suit me.  Hulu has more than I can watch.
"Always work from the general to the specific." J. Raabe

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Offline muldoon

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Re: DIY HDTV Antenna
« Reply #4 on: November 10, 2009, 08:49:14 PM »
Way cool!!  Is that through an asphalt shingle roof? 

Yes, it is in the loft and receives reception through an asphalt roof. 

I've got my old 1985 Radio Shack antenna up on the roof which catches about 80% of the stations in the Seattle/Tacoma area - except on stormy days when the signal breaks up from several stations. I'm going to dig deeper into your links and see if I can improve that.

Check out tvfool for your area to get an idea of what you may potentially get, from there it's a fine tuning act to pull them in.  I'll help if I can. 

Great and very interesting, muldoon.  If I watched TV I would try it.  I find enough TV on the computer to suit me.  Hulu has more than I can watch.

Yeah, I don't watch tv either at home.  There is no internet up in the country for me aside from some light blackberry use.  I like football, and enjoy watching the games.  Aside from that, the show I like on PBS is called Austin city limits.  A local area texas music tradition where they show some live broadcasts.  This past weekend they had Band of Heathens, a local Austin band.  I also saw Taylor Swift on Saturday night live.  god I bet Hank would cry if he saw what country music had become these days, what are those Nashville people thinking these days?

Anyway, that ole Austin city limits sounds easy on the ears of this old Texas good ole boy.

   Jackson Station
  Jenny was a keeper
Cornbread

Offline glenn kangiser

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Re: DIY HDTV Antenna
« Reply #5 on: November 11, 2009, 08:27:47 AM »
I used to watch Austin City Limits in the valley.  It was one of the few good shows.
"Always work from the general to the specific." J. Raabe

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Offline considerations

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Re: DIY HDTV Antenna
« Reply #6 on: November 11, 2009, 08:33:39 AM »
You can watch Austin City Limits on the PBS Website.  c*

Offline MountainDon

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Re: DIY HDTV Antenna
« Reply #7 on: November 11, 2009, 09:35:59 AM »
Where I am internet access requires satellite. That's worse (more expensive along with a contract) than getting OTA TV.  :( :(
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline muldoon

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Re: DIY HDTV Antenna
« Reply #8 on: November 17, 2009, 11:30:51 AM »
A quick update on where I got to in adding VHF support for the antenna.

I found multiple people online who had ran into the same situation as me, where they built essentially the same design got great results for channels 14 and up but poor or no results for anything under that.   In adding VHF, I found these two youtube posts that gave me some ideas. 

- he went to the dollar store and bolted on a rabbit ear.  While perhaps it would worik in the city I didnt think it would pick up what I needed at the distance.  It also seemed kinda ugly and "wrong" to add a made in china junky rabbitear to a home made setup. 

  and   - this guy did essentially the same only taking an older powered amplified antenna and gutting it to steal the VHF element.  Again, he used what he had and I aimed to do the same.  I did not have the powered antenna, nor do I want another power sucking device required.  However, for others it may be useful.

On to some antenna theory.  Basically the lower the frequency, the longer the wave - which is why the smaller whiskers of the previous antenna works just fine for those channels in higher frequencies.  An antenna works by resonating at the frequency of the wave.  Much like in tuning a guitar, fretting the e string on the 5th fret will cause the a string to vibrate all by itself because they are "in tune" with each other and will vibrate / resonate at the same frequency.  The same is true with opera singers who can hold the note (frequency) at which crystal glass will resonate causing it to shatter.  Or the loud car bass outside rattling your windows.  etc, etc. 

Given each channel has it's own frequency or spot on the dial, to approach this task I set out to determine what the optimal characteristics would be to capture what I was missing.  I was only missing a single channel, channel 7.  No other VHF channels are available to me, so I do not need to make an all purpose antenna, just an antenna to get channel 7. 

Looking around, I focused on essentially the same design I have used for FM radio antenna.  The folded dipole. 
http://www.wfu.edu/~matthews/misc/dipole.html

That website lays out the basics of the approach, determine the channel frequency, determine the length you need, make the antenna. 
Channel7 is defined as f (in MHz) = (6 x channel_number) + 135. - or 177

To determine length in feet for the optimum antenna, take 468/F, or 468/177 = 2.64406779 feet, or 31.72881348 inches to "tune" into channel 7. (For reference, a "channel 2" antenna would be 8.3 feet in length for halfwave or at least 4.17feet for quarterwave, those lower VHF channel require larger antennas)

I then found this website as well, which gave me the ideas on how to make one more robust that I think has a good chance of picking up signals very far away.  http://pigtail.net/nicholas/ctn/dipole.html

This is what I came up with over the weekend, its 1/2" copper pipe, some elbows, and mounting brackets. with a 2x4 standoff. The length of it is 31.75 inches, and the copper mounting brackets are the point at which I will attach a balun to. I intend to replace the 2way splitter I have with a 3way splitter running both uhf's and this vhf.

btw, my costs are now up to 21 dollars total for this.   Hoping it will work, I'll post an update the next trip up.



Offline muldoon

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Re: DIY HDTV Antenna
« Reply #9 on: November 25, 2009, 02:03:50 PM »
Quote
Hoping it will work, I'll post an update the next trip up.

I love it when a plan comes together.  Added the vhf addition, and used a 4way splitter (didnt have a 3way) and channel 7 came in perfectly.  I was able to see the cowboys redskin game on sunday, and even got some king of the hill, family guy and simpsons cartoon geekiness as well for fun. 

I think it's safe to say it works, even at 70 miles it works great in my opinion.  I am about finished with this project and really cannot see anything else that needs tinkering on it.  It has been fun.  I hope this encourages others to pursue something like this for themselves if it interests them.   

my total cost was about 20 bucks. 

the updated antenna



channel 7 working, listed in the first page of channel listings



the final install




Offline glenn kangiser

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Re: DIY HDTV Antenna
« Reply #10 on: November 25, 2009, 06:26:12 PM »
Very scientific and cool, muldoon. Thanks.
"Always work from the general to the specific." J. Raabe

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Offline muldoon

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Re: DIY HDTV Antenna
« Reply #11 on: October 17, 2011, 08:28:02 AM »
Quote from: muldoon
I am about finished with this project and really cannot see anything else that needs tinkering on it.  It has been fun.

Well, I did eventually find something that needed tinkering with it after all. 

I have an older stereo at the place and over the years had consistent problems with radio stations fading in and out over time.  They just never seemed to really lock on.  I added an external antenna, the 300ohm flat ribbon style you may be familiar with.  I used clamps to stretch that antenna out in the ceiling joists.  Some weekends were good, some not.  I decided to attempt to build a decent antenna for FM radios and set out to read up on it. 

(https://countryplans.com/smf/proxy.php?request=http%3A%2F%2Fecx.images-amazon.com%2Fimages%2FI%2F31fowd9-STL._SL500_AA280_.jpg&hash=710ba0a576e18696bac2e769a26b01ce691511e2)

Turns out FM signal frequency is basically the same as right around channel 6-7 on the TV frequency, and of course I already have a TV antenna.  All I needed was to break out the FM signal from the antenna.  Enter this, a band seperator from wineguard.

(https://countryplans.com/smf/proxy.php?request=http%3A%2F%2Fpimages.solidsignal.com%2FCA8800_medlrg.jpg&hash=5f507de11607c21acfc34b8098e9c9cd369934f5)
coupled with another balun to get the 75 ohm back to 300 ohm inputs on my old stereo. 
(https://countryplans.com/smf/proxy.php?request=http%3A%2F%2Fpimages.solidsignal.com%2FTV-2900_medlrg.jpg&hash=7bc8e0c0552292adca25671a05388ce9fe59d55e)

I have no discernible signal loss at the TV so it is very passive and I now get great FM reception as well. 

Offline varian

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Re: DIY HDTV Antenna
« Reply #12 on: June 06, 2013, 03:09:29 AM »
Hi Muldoon,
  I like your Antenna. I want to build one too. I live in Willimantic,ct. I want to put Vhf on my Antenna too. I have channels that are 30 miles to 120 miles. How far does your Antenna pick up VHF from? What kind of parts or things did you use to build your antenna? I want to make my VHF like this

What length would the aluminum tubing have to be to pick up the different vhf channels in my area from different miles? Here is a link of channels in my area http://transition.fcc.gov/mb/engineering/maps/ type in 06226. Thank you very much for any help you can give me. Also here are my VHF Channels. Email me back.

 


WCVB Channel: 5 (RF 20) 5.1 ABC Distance: 65.4 miles
433 meters above sea level
 Effective Power: 625 kW

 

 WGBH Channel: 2 (RF 19) 2.1 PBS Distance: 65.4miles
417 meters above sea level
 Effective Power: 700 kW
 

WHDH Channel: 7 (RF 42) 7.1 NBC Distance: 66.3 miles
331 meters above sea level
 Effective Power: 1000 kW


WBZ Channel: 4 (RF 30) 4.1 CBS Distance: 65.4 miles
434 meters above sea level
 Effective Power: 825 kW


WFSB Channel: 3 (RF 33) 3.1 CBS Distance: 31 miles
375 meters above sea level
 Effective Power: 692 kW

Thanks,
Varian

Offline MushCreek

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Re: DIY HDTV Antenna
« Reply #13 on: June 07, 2013, 01:28:53 AM »
I'm back to messing with antennas again myself. I have a DB4 on a 30' mast with an amplifier, and get OK reception from nearby transmitters, but ABC is 33 miles away, and it was sketchy until the leaves came out on the trees. Now it's GONE. I've been told it is a VHF transmitter, so maybe I need to add that. Part of the problem is that station is not line-of-sight because of mountains in the way. When I did get it, the signal direction was about 70 degrees off of what it should be. Maybe I'm getting a reflected signal off of something? Are the leaves on the trees my problem?

I hate digital TV. No cable out here, so I'm stuck. I don't want to pay for cable or dish anyway. I can SEE the transmitter towers from the closer stations, and yet I still lose signal from time to time.
Jay

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Offline Bandits Papa

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Re: DIY HDTV Antenna
« Reply #14 on: March 27, 2014, 01:31:08 PM »
Well I see that it has been 120 days or so since anyone posted a reply to this topic.. probably had satellite TV like me during that time.. just wanted to comment on my home made HDTV antenna and this site in general..  first, I had DirecTV for the past 6 years. I live in the country and thought that was the only way for me to get decent tv channels.. and it was and wasn't..

The costs in the end did not out weigh the product I was getting..

Been a week without my television habit.. no big deal, sort of missed the news, military channel and history channel but that's about it.. the TV is sort of just a grown up baby sitter that sometimes I find entertaining..

But I wanted TV some, without the high costs of satellite.. enter the internet and antenna searches.. without being to long winded... I made what come call a DB4 I guess.. I noticed the plans on Popular Mechanics, and several other DIY sites... basically a piece of wood 22 " long 3.75 " wide..  4 metal coat hangers, home made washers, shop screws, TV twin lead line and some old coax I had laying around.. ( I dabble in amateur radio also) so lots of electronic pieces and parts to be found here... anyway..

The hardest thing for me was figuring out my TV's built in digital tuner.. never had messed with it but I worked it out.. what I built isn't pretty or exact.. it's inside behind the television now and working.. I get two of the 3 major carries, and two other smaller carriers plus  two channels I had not heard of or watched before.. and for that I am pleased.. now that I know this trash can antenna ( play on words) actually can work, I'll pursue more detailed and exterior models in hopes of grabbing even more "free" TV..


SO to anyone wondering if they can build an antenna for digital TV, like all these folks I have read up on this past week, I too will say YES YOU CAN.. just do it.. and good luck..

Offline Huge29

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Re: DIY HDTV Antenna
« Reply #15 on: April 27, 2014, 02:36:34 PM »
Very cool, great info!

Offline MushCreek

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Re: DIY HDTV Antenna
« Reply #16 on: April 29, 2014, 09:31:17 AM »
Hmmm. The only weak channel here is 13, which is ABC. I made a dipole using the data, and it doesn't work. As a matter of fact, I get 13 more reliably from the UHF antenna than I do from the dipole. Interestingly, the dipole does receive all of the UHF channels I was getting before. ???

13 is not line-of-sight from here. When I do get it, it's not coming from the direction it should be, but about 60 degrees off of that. Maybe it's bouncing off of another mountain? Any one know if a VHF SWR gauge would be useful for tuning antennas? The TV has a strength meter, but it only works if you are actually getting a signal at the time. I assume the SWR meter would get something, from which I could fine-tune the antenna and direction to maximize the signal.
Jay

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Offline muldoon

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Re: DIY HDTV Antenna
« Reply #17 on: June 03, 2014, 04:36:00 AM »
mush, did you go to tvfool and view the signal locator?

https://www.tvfool.com/?option=com_wrapper&Itemid=29

You enter your exact address, and the height of the antenna details.  It will give you a fairly clear picture of what is available to you in terms of how the spatial rf modulation works.  they have a google earth mapping ability too, sometimes it is easier to understand how different channels work when you can see it on a map. 

https://www.tvfool.com/?option=com_wrapper&Itemid=90

enter address, make it plot, then select channel from the bottom.  will help you get an idea how different frequencies "move" around differently. 

also, channel "13" is vhf, however keep in mind that just because the station calls itself "13" does not mean it actually broadcasts on channel 13.  look on the tvfool listing for real and virtual channels.  the virtual channel is sometimes different because a station may have been on the old analog system using that frequency and moved.  the virtual is what shows up in the tv display, the real is what the antenna sees. 

Offline MushCreek

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Re: DIY HDTV Antenna
« Reply #18 on: June 04, 2014, 02:11:10 AM »
Yeah, I've been to tvfool. ABC is in fact channel 13. It's also the only one that isn't LOS, although they list it as being possible. We get it on our dinky little 22" cheap TV, but the much more expensive Samsung only gets it on rare occasions. There's no point to moving the antenna any higher; even at 200' the ratings on tvfool don't change.
Jay

I'm not poor- I'm financially underpowered.

Offline Dave Sparks

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Re: DIY HDTV Antenna
« Reply #19 on: June 22, 2014, 06:30:32 AM »
Some of the modern digital TV tuners have a pre-amp that is switched in from the remote.  On a LG and Vizio there were settings that could increase the gain on a VHF channel.  Here in Mariposa we can look at Sacramento and the Bay area at excellent PBS channels on VHF. KVIE is an awesome PBS channel compared to the one out of Fresno.
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Offline sabinelr

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Re: DIY HDTV Antenna
« Reply #20 on: August 27, 2014, 06:50:06 PM »
I like that dual-bay antenna.  I sort of did the same only 4-bay with cheaper materials - some furring strips, #12 house wire, about 3 feet of screen, and some more wire for two more bays below and single-wire reflectors.  For insulation I have some plastic that I cut from the wall of my plastic shed.  It's up about 15 feet off the ground, and looks suitably grotty from the street.  Not sure if it is good or bad, but it works as good as one of those mail order things: 

http://www.amazon.com/Amplified-Digital-Motorized-Rotation-Infrared/dp/B004NQMCDK/ref=sr_1_1?ie=UTF8&qid=1409197030&sr=8-1&keywords=hdtv+antenna+outdoor

I made another single bay with no reflector as proof-of-concept that works moderately well.  It is hooked up to a HDHomerun box and I can watch the local channels with VLC if I turn it right.  That one uses a sawed up plastic cutting board as the insulated part, screwed to a furring strip for mounting purposes.

From Renton, both antennas pick up all stations in the Seattle metro area - 51 total including secondary channels.  The signal on the four-bay is good enough with a preamp and 100 foot drop cable to record HD OTA with.  Still can't get KVOS in Bellingham, although I would occasionally pick it up with the Radio Shack fringe VHF/UHF antenna, but I gave that to my daughter.

I would post a picture, but the antenna broke the camera.  Just imagine the ugliest thing possible, and it's worse.

Those Hoverman-Grey antennas look simple, and amazing results are reported.  Probably the next project.

Offline DrunkFerret

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Re: DIY HDTV Antenna
« Reply #21 on: October 06, 2014, 12:11:25 PM »
So I live on the east side of Fort Worth, TX and got disgusted with trying indoor antennas (stupid apartment rules and ground floor). So then I went to Fry's. Got this little guy ( http://www.frys.com/product/8228486?site=sr:SEARCH:MAIN_RSLT_PG ) and used my own amp (25db), FM trap, and good RG6. Was disappointed at first until I folded two of the director elements in and started dialing in my azimuth. I have been to TVFool and looked at all the channels I care to get as well as using the terrain overlay (love btw). I did this fine tune last night after my girls shows were over and 30+ channels. Before I did this last tuning I spent some time making a DB4 with a VHF biquad element (?silly?). Now that I get all but one set of channels, 27.1 - 27.3 (36 real ch) -64.6db @ 21.9mi 5deg off the others I care for. In fact all the channels we care for are only +/- 5deg from each other (I know, good for us). At this point I don't think it's worth it to use the DB4 I made. In stead I'm thinking that I will get another Naxa NAA-351 and connect them together. Also I'm thinking of separately amplifying the UHF and VHF signals before combing them for the TV. I want to use the Naxa as it saves on space and money ($25). Any ideas on placement? Side by side or over under? I get the 27's but spotty, and I'm thinking i just need a little more gain to get them stable.

 

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