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Picture of Build a Large DB8 HDTV Antenna: Big Bertha
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Update May 2015: this antenna was built in 2009. It is now 2015. We still have it and it's still doing it's job. I've since put an amplifier on the mast and we now can get that fringe channel lightly to the left of the others without any longer having to use the rotor to turn it. Actually, I leave it set facing the fringe channel and the stronger ones are the ones that compensate. I go up on the roof to check things every couple of years and so far all is well. I would recommend stainless hardware throughout if doing this. My plated stuff is doing well but stainless would have given many, many years of carefree use. Oh, I also now have a 60" Sony Bravia LED instead of the old Sony analog TV we had at the time of the original construction.

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Original Post

We've had Cable TV and Cable Internet. It seems that there is less and less on cable than there ever was. Cable in my area is $49. I eventually cut down to basic for $20 and supplemented with Netflix. Netflix is excellent by the way but that's another story. We also have my macintosh connected to the TV so we can Hulu any program that played recently.

I'm finding that even basic cable has little 'value'. By value I mean I get the basic local channels and a bunch of junk otherwise. The channels I look at I could get for free if I used an antenna. Hence, I've decided to minimize.

Here in Southern Maine the TV stations are mostly in Portland about 30 miles away. Some are further, about 50-60 miles away. Most HDTV antennas work for 30 miles and a few claim to get up to 60 miles. I decided that I need more antenna than that. Something where 60 miles might be the limit but a doable and good limit. I've decided to produce a DB8. A DB8 antenna has 8 receiving elements, or 4 pairs of elements. It's basically two DB4 antenna's combined. The last picture in the segment is a commercial one.

What follows is my foray into the world of HDTV antenna construction and trying to squeak the most out of it for a moderately fringe TV area I live in.

BTW, the last segment contains all kinds of HDTV signal information and links to places to assist you in learning more. I was a teacher for 30 years (no I don't want any help with my grammar, I said I used to be a teacher) My job was simplification and clarity. I hope this instrucatble is up to that.

 
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Msgough889 days ago
I was curious as to whether you have the radiation pattern for this antenna or if it is similar to the Antennas Direct db8 radiation pattern
deceiver (author)  Msgough889 days ago
No, but it should be similar.
Thank you. That's what I was thinking too and planning on using when I point the antenna. I'm hoping to catch 2 major broadcast areas that are approximately 160° from each other.
PeterD13 made it!24 days ago

In all I've built 3 so far, each pointing in the 3 main directions that my local transmitters are clustered. Most signals I'm picking up are around 30-40 miles.They are installed in my attic hung from the rafters with the L bracket shown. They work very well, and are DIY cheap if you are creative. I built all three for about $5. The only items I needed to buy were the baluns, which proved to be a challenge in today's cable/satellite world! For the phase lines I used 12 ga. solid copper stripped from some scrap Romex, and for the higher gauge bare copper elements I found a short piece of scrap high voltage wire that was stranded. Pulled apart, the 10 ga. individual strands were perfect. The wood came from 4' planks on pallets, screws and washers were whatever I had laying around. Sometime in the future I do still plan to build an outdoor antenna, with an array of 2 or more as deceiver has built.

Lessons Learned:

*Baluns are hard to find nowadays! You can buy them online, but over time I did find them here and there at big box stores.

*Direction is everything. Satisfied with your reception? Keep playing until you are certain you have the best reception possible. Drift will occur from AM to PM, and less often in weather. Although digital is 'All or nothing', I've found lower signals will still produce some ghosting effects even while holding a solid picture.

*I tried several methods for stripping the insulation off the middle sections of coated wire. Best I found was to slice the top and bottom of the section with a wire stripper, and just pull it off with a pair of pliers. Or you could burn it off as deceiver did :) This is hands down the most tedious process of the build.

*If you plan to build more than one, build just one at first. It helps to learn from the experience of one, and using the finished antenna as a template for measurements on the rest will speed things up tremendously.

*On the elements, lower gauge (thicker) you can find is better. These whiskers are prone to any little bump or nudge. I found the 12 ga. wire I used on the first antenna would bend easily and required regular adjustment. This doesn't affect the phase lines of course, so a higher gauge is acceptable.

*I used the L brackets I had laying around to mount, which helped keep the antennas steady but adjustable for fine tuning. I screwed the long section on the rafter, and screwed the short end on the top of the antenna allowing me to turn it left-right.

In all great build. Simple, Fast, Effective.

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Divet3 months ago

Does it matter which wire is on top at the crossover? Do you alternate?

deceiver (author)  Divet3 months ago
No, as long as they are not touching (Insulated from each other).
deceiver (author)  deceiver3 months ago
Some TV's will show you a signal strength in db. 0-100. At the same time check a channel with one antenna then the other. Of course to make it good science it would have to have similar parameters. Same tv, about the same time, same height, same location, etc. Good luck. Fractal stuff should yield some good results from what I've read.
deceiver (author)  deceiver3 months ago
Yes, I see where it says that. Actually, it doesn't matter for signal integrity. If someone were to use bare wires then it would be important that they don't touch which is probably why I added it years ago. If yours are covered by insulation then they can touch, mine do. It shouldn't make any difference. Thanks for clarifying though. Someone else might have the same question.
PeterD13 deceiver3 months ago

Thank you both, I'll be building two more of these soon. Knowing that will make it a little simpler.I'm putting together a couple fractal antennas as well to compare, though I don't have any good way to measure the actual performance of each individual antenna.

Divet deceiver3 months ago

So the 1 inch air gap is necessary even if the wires are insulated?

deceiver (author)  Divet3 months ago

Hmm.. no. I don't think I mentioned any air gap in the instructions. If insulated (plastic coating) the wires can be touching.

PeterD13 deceiver3 months ago

The diagram for the phase lines states to keep 1" of space at crossover, nothing mentioned that insulated lines would negate this. I interpreted it the same way and place a 1" block of wood between insulated 12 ga copper at crossover.

brent.batali4 months ago

Great diy project!! I have what might be a stupid question. I looked up my address on antennaWeb to determine where to aim this antenna (if I decide to build it or buy it). All of the channels range from 156-180 degrees from my house 15-64 miles away. If I built 2 or even 3 of these and instead of combining these as one large flat panel but instead had a slight angle to each attachment would this work instead of a rotor? Trying to keep my wife happy with this "getting rid of cable thing" and if she has to push a button other than the remote... wouldn't be the end of the world, but it would definitely open up the conversations every time I want to spend money on golf

Pilgrimm4 months ago

OK, it's six years on, but Instructibles never throws anything away.... (just like me!) Your 'ible is Brilliant! Simple, easy-to-follow instructions, cost-conscious, and lo and behold... It Works! (The Real Test) I built a smaller version 3 years ago because the commercial antennas were ridiculous. Works OK, and it was free, beyond cost of materials - about $20.00 including shop scrap. I'm retired, live south of Hartford, CT (and I get a couple of NYC stations - 140 miles) and this will do nicely until Social Security starts to supplement my TV costs. Many thanks. And may the force be with you!!

Goofus526 months ago

In making your whiskers you used 6 gauge wire. I have a bunch of surplus solid 12 gauge wire laying around, so would it be the same if I braided to 12 gauge wires together to make each whisker? I know it'll take a little time but in this case, time is cheaper than money.

deceiver (author)  Goofus526 months ago
I only used heavier wire so that It wouldn't sag, or bend over time. I suppose you could twist a couple of 12's together. It would probably be pretty resistant to bending. It shouldn't affect the signal any as far as I know.
mtsav8or7 months ago

Thanks for posting this build. It answered a lot of questions I had about connecting multiple antennas to create an array. What are your thoughts about connecting two antennas facing in opposite directions? My closest stations are positioned almost 180 degrees from each other. I know I could add a rotor but I'm looking to setup a DVR system and want to record channels from both directions at the same time. I haven't tested an Omni directional but I'm in WV and live in a valley with 400 feet of hills in all directions.

deceiver (author)  mtsav8or7 months ago
Yes you can. A digital antenna mounted on top of each other pose no interference issues with the other antenna. A rotor is an option but it you want two antennas and the stations are 180 degrees from each other then you'd never have to move them.

If on of the stations are close compared to the other maybe a smaller antenna might work in that direction. If that's the case it would save a lot of work and expense. Remember the digital signal will either be on or off. No snow or weak signal issues like VHF used to be. If you get it then it's good.

Not sure if you can help me. Am trying to get rid of cable, and purchased two Leaf50 HDTV antennas, which get signals up to 50 miles away. With the Leaf50, I get the basic channels I wanted, except for NBC. NBC broadcasts from 70 miles away. Is there some way I can enhance these Leaf50's so they can get a signal from that far away? I don't think some kind of antenna outside, on the roof, or in the attic can hook up to both tv's of mine (1 upstairs in the living room and 1 downstairs in the family room), right? Please write me back at jeannebeans@gmail.com. Thanx!

deceiver (author)  laura.brown.3557447 months ago
70 miles is the absolute limit unless you are up high. Digital TV is line of site pretty much. Higher up and you can do further because you can get beyond the ground level curvature of the earth. Your leaf antenna is a good indoor antenna but not like one of the larger roof mounts. When you see reviews of any antenna you'll see people who love them and those who hate them. The reason is that someone in the middle of a city where all the stations are, will get a signal for 50 stations with something very small. While others with huge antennas but living far from stations will think it doesn't work. Yours is good for signals maybe up to 30 miles away. 50 would be pushing it.. unless you're up very high. You can put this antenna or one on the roof hooked up to two tv's. You just need a splitter (radio shack, walmart a few bucks) You lose a couple of decibels of signal but it does work well. Too hook it up you connect the coaxial cable into one end of it and there's two connections on the other side of it that go to each TV. A larger antenna, mounted fairly high up on the roof with a splitter and maybe a mast mounted amplifier 'might' get what you want. It all depends on the terrain (mountains?), distance to the station, and another factors is how much power the station is transmitting with. There are links at the end of my instructable that will let you type in your zip code and it will tell you the possibility of tuning these stations in. It takes into account the topography of the land, asks you how high you'll mount it, and a bunch of other factors. It is pretty accurate actually. Good luck with this. The other option is to have a smart TV and get a service like HULU that lets you look at last nights tv programs the next night. It works well and is about $8/month. Let me know what you end up doing and if you have any luck with it. If something isn't clear here please don't hesitate to ask for clarification.
Ray.P.Waddell9 months ago

Is 19ga 1/2" hardware fabric good for the reflectors?

deceiver (author)  Ray.P.Waddell9 months ago

yes, as a matter of fact that's what I used. it's 1/2" squares of galvanized mesh. Anything's okay as long as it's no more than 1" square mesh. And of course any solid metal would probably be taken out by the wind.

The mesh you're talking about is still bendable but stiff enough to last the test of time. And being galvanized is important in the weather but won't affect the signal at all.

john.wraith.512 months ago

This is definitely one of the better home built antennas, I am currently building one similar to the DB8E on a PVC frame and can tell you have done the research on this.

one small comment though , I think you meant to say cut the wires at 19 not 18 ( unless i am not understanding correctly)

One thing I havent found any info on the whiskers being swept forward increasing directionality, also when making an array did you come across any info on the distance between them?

Outstanding job on both the antenna and instructions

deceiver (author)  john.wraith.59 months ago

You're right about the 19" instead of 18". Thanks for pointing that out. The reason for the bent whiskers and background signal reflector is that if the reflector and whiskers are flat, the reflector will reflect the signal directly to the back of the whisker. It would only have to be the width of the whisker.

By raising the whisker higher above the reflector and tilting it forward, the reflector can be made larger with more area reflecting onto the whisker. Think of it this way. The further you move the whisker away from the mesh, the more it begins to act like being closer to a focal point.

Now, this isn't a direct TV reflector! There's a point of diminished returns. If the whisker is an inch above the reflector then flat is good. A little higher lets you add more reflector maybe getting more signal to the antenna collector (whiskers).

vuk651 year ago

Great Job! Did you try only one antenna before you set up the array to see if it made a difference? Also, I would like to put mine in the attic. Can I use foil sheet on cardboard as a deflector? I have already made an antenna but I really like your design!!

deceiver (author)  vuk651 year ago
Tried only one smaller one.
out of the wind anything metallic should work.
Dano6691 year ago

I am on a hill, on my street. It is 139miles to Boston from town. My LOS is not real good, unless Boston is more direct across the water. I know driving down I295 there is a nice hill, about 295' elevation. I do believe that I am on a high point in town though. The humidity is having a factor in it as well, normally can get most of the station down there at 75% or better, when we are about 50% humidity.

deceiver (author)  Dano6691 year ago
A hill of that height would be like having an antenna mast that high. Low humidity is better. The more moisture in the air, the more the signal is absorbed. 139 miles is a long ways. Even an elevation like yours doesn't seem high enough to overcome the earth's curve. Are you sure it's Boston? I'm 90 miles from Boston and can't get them.
Dano6691 year ago

Hello, I am also in Maine, South of Augusta. I was wondering how high you have your antenna and which stations you were picking up? I recently paired up a couple of 8-bay antennas and now find myself receiving a lot of Boston channels on top of those from Maine. I was wondering, if it was something to do with the weather. Not sure how much longer my DX-ing will be going for, I hope a long time.

deceiver (author)  Dano6691 year ago
Weather only hinders signals. It wouldn't help. I'm impressed that Boston stations would come in. You're what, about 200 miles from Boston. The only way that is physically possible is if your elevation is very, very high. Anything over 70 miles, line of sight at sea level should not be possible because of the curvature of the earth. The distance to Boston form around Augusta is only available with a good antenna and elevation. Bravo for you if you have that situation.

If you are then the Maine stations are pretty much on the coast in line with Boston.
Wooodyii21 year ago

Hello again, Is a splitter and a combiner the same thing? I have seen splitters at the store with 1 input to 2 outputs, but nothing 2 inputs to 1 output. How much roughly do you think the antenna itself cost you? Lastly, would drywall corner bead be good enough for the parameter of the antenna or is the aluminum angle the way to go?

deceiver (author)  Wooodyii21 year ago
yup, splitter/combiner is the same.

I've seen stiff and very thin drywall corner bead. You'd have to judge yourself depending on what you find.
Wooodyii21 year ago

Hello, and great write up. I will be making 2 of these within the next week and both will be twin arrays. Is there any thing you would have done any differently for better signal or is this pretty much the pinnacle of the design?

Sorry, one more thing. The distance from the antenna to my tv is probably going to be about 40 to 50 feet. Is there any other steps or details I should be aware of because of the distance? Thank you

deceiver (author)  Wooodyii21 year ago
There will be a slight loss with longer cable. check it out and if you're not getting the stations you expected to then an antenna amplifier would help. If everything works okay though, why the added complexity and cost.

Thanks for the info. Stainless it is then.

deceiver (author)  Wooodyii21 year ago
Actually no. I probably would have mounted it a little higher if I could. I might have forgone the rotor as i don't seem to need it with stations almost in the same direction. I'm fairing well so far but to do it again and some day I probably will do this. I'd splurge for some stainless steel screws/bolts and such especially where wires connect.

Good luck.
rambler501 year ago

I made 3 of them 1 for me 2 for a friend. They do a great job, they look very professional.

deceiver (author)  rambler501 year ago

I'm so glad it worked out for you. My antenna is still working great after all these years. That, with cutting the cable, amazon prime, hulu plus, and a mac mini downloading other stuff and we're very happy with our entertainment bill with only internet being payed for.

deceiver (author)  deceiver1 year ago

Hey, post some pictures huh?

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