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Build a Large DB8 HDTV Antenna: Big Bertha

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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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vuk6517 days 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)  vuk6517 days ago
Tried only one smaller one.
out of the wind anything metallic should work.
Dano66924 days 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)  Dano66923 days 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.
Dano66925 days 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)  Dano66925 days 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 month 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 month 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 month 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 month 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 month 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.
rambler502 months ago

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

deceiver (author)  rambler502 months 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)  deceiver2 months ago

Hey, post some pictures huh?

An updated link for the diagrams
http://m4antenna.eastmasonvilleweather.com/Drawings/PDF%20Drawings.html
Oh, yes forgot to mention since it was going in my attic, I made mine out of 1/2" PVC pipe for the frame, and an aluminum window screen for the reflector. The array mount was a 3" wide piece of pine. I used 45 degree connectors which I sawed "nearly" through and bent out to the right angle
I built this and boy does it work great, even in my attic!

Since I live in an area where there are a few channels in the high VHF range I modified the antenna a little so that the last pair of wiskers are were cut to 29" and bent to 14.5 V 14.5.

Since the focus for those frequencies is further out, I also made the piece of wood that the antenna array is on sit at an angle to the reflector, with the top of it about 6", and the bottom out about 15".

It's best to experiment with the distance from the reflector gets the best signal by moving piece of wood around while you have a TV attached till you get all the channels you are looking for.
where did you get this plan from. or is it of your own design.
thank you
if you made four (two in a set) and put them on either side of the house could I get better signal?
deceiver (author)  Firewire Pro1 year ago
Yes, more collection area the better the signal. But... if you're getting all the stations within line of site with one segment or two then adding more won't help. With digital you either get the signal and see a picture or you don't. So, a good antenna will see what it can see from what is being sent to it. If a station is behind a mountain then it doesn't matter how big the antenna is.
jrbilodeau1 year ago
Not sure if i missed it, but how far away did you mount the reflector from the whiskers?
koda571 year ago
I built one of these antennas , thought i would have to build the set of 2 because i wanted to pick up fox which is about 50 miles away ( the way the crow flies ).
However the one ( 36 x 40 ) did the job.
louisrosa1 year ago
wow--what a workshop. you could make anything in there. congratulations on the instructable, the pics are great and the antenna fine. i really like the ship however
jmiller902 years ago
I have an old home with a basement full of old window screens. What do you think about using the screens as reflectors? I too am trying to cut the cable. Thanks for your ingenuity.
deceiver (author)  jmiller902 years ago
I'd not think so. First the screen has to be metallic. If it is okay but then if you've ever walked with screens on a windy day while putting them in you've noticed that they can act almost like sails. The screen would wobble the antenna and disrupt the signal. They might also come down in a big wind too.

The wavelength of the antenna is such that any mesh one inch or smaller will suffice. The 1/4" mesh I have is fine, 1/2" would have been just as good. A few feet of a roll at a hardware store is only a few bucks and is stiff so that it mounts good and is durable.
Hamosia2153 years ago
Anyone ever try to make 3 or 4 of these and combine the signal? Any thoughts or advice with this idea? Also stacking them vertically doesn't have any negative effect on the signal? Thanks for your reply!
Stacking vertically makes the signal reception swath VERY narrow. Horizontal stacking is better for most issues, but they must be perfectly balanced. If your coax lines are even 1" different in length to the combiner you will get signal loss.
deceiver (author)  Hamosia2153 years ago
You lose a little with the splitters but combining more should make the array signal stronger just as putting these two together does.

Ghosting used to occur if you put two antennas close together when we did VHF but the digital nature of the UHF signal isn't affected by this. So, stacking antennas used to be a no-no with VHF. With UHF digital you can stack all you want. The added benefit of stacking is that you have less effect of side to side movement by the wind so for fringe stations your signal is better aligned in windy situations.
ok, (I'm the Village Idiot) on a good day, but I was wondering.....(which is questionable with a negative I.Q.) but what if someone took a balloon, a heavy duty one, an attatched the big bertha to it if in fact it would be possible to pick up signal over a mountainous area, errr even practical....I got a spool of cable wire I found in a dumpster several years back an its just sitting there an well if in fact it did pick up "signal" is there anything a body could pick up at Radio Shack that would extend the signal area such as I'm a 1.5hr drive to Vegas an even get some Vegas station's now but mostly Phoenix an well I get 24 channels now but am greedy. I am disabled with an amputated leg so cuz of the pain I have to limit physical excertion but wondred if this may be a possible way to pull in more channels!? Anyone have any suggestion's that don't require a heckofalot of brain activity an physical labor? I'm all Rabbit Ear's! (no pun intended)
deceiver (author)  desertrat112 years ago
The antenna has to be positioned pretty specifically at the station. I don't know how you'd keep it steady with this method. And even though you're in a dry area, watch out for lightning. Nasty stuff.
I have just made an antennae according to your post and I will admit I was skeptical about it actually working but times are tough and we couldnt afford satelite service anymore so we looked for options we were going to buy an antennae but by the time we would have been done it would have cost us close to 200.00 dollars because we are also 50 - 70 miles from any transmitter in the past about 20 years ago we had a regular tv antenna and could only get 3-5 channels and depending on the time of day very snowy reception, so when we told our kids we were going to do this and explained that the picture wasnt going to be what they were used to , We were all amazed at the clarity of the picture and reception we had been in the dark about free OTR television because we had been so used to thinking we had to have satilte for reception in our area, now we are mad at the amount of money we have wasted paying satilite companies, and want other people to know if they are having it rough , they can have free tv,
Thanks for the info.
deceiver (author)  lynbrookinc2 years ago
So glad it worked out! It felt good to cut the cable for us.
I forgot to tell you in my first post that we made the antenna out of materials we already had except for the 2 baluns and signal combiner, we alsio bought a cheap amplifer that actually does increase the signal on some channels for us to view them.
deceiver (author)  lynbrookinc2 years ago
I still have my amp that I haven't installed yet. Things seem to work well without it. I may put it on sometime though just to see.
niko753 years ago
at what distance captures this antenna signal that I'm 70 miles away and did not know I will make this antenna work or not?
deceiver (author)  niko753 years ago
Odd wording of your sentence. I'll attempt to answer it. 70 miles is a far distance but it's also determined by line of site. If you've got hills or mountains or lots of trees between you and the tower then it might not reach. Look down in the instructions I give and there are links that will let you type in your zip code and help you determine the signal strength of a station from it to your house. It will also show you the terrain between it.
halstead3 years ago
I constructed test configurations of the "Gray-Hoverman", "Coat-Hanger (or db4) with 7" whiskers" and your configuration of the "Big Bertha" with 9.5" whiskers and oversized reflector using 1/2 inch hardware cloth. The test configurations were all made of wood. After testing each, the "Big Bertha" exceded both the "Gray-Hoverman" and "Coat-Hanger" designs. I am located 30 miles from a cluster of TV antennas that serve the Sacramento, California region but my precise location is behind a rather large ridge with no direct access to line of sight transmission signals. The other antennas had signal strengths that varied from 72 to 100 percent. However, I now have nearly all channels registering between 92 and 100 percent signal strength. Thanks for the design. By the way, I am replacing a rather large Channel Master VHF antenna that had a range of 70 miles but only produced signals in the 60 to 80 percent range.
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