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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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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
jmiller901 year 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)  jmiller901 year 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.
deceiver (author)  halstead3 years ago
That is very interesting. I always wondered how it would stand up to other designs. The commercial ones try to use numbers to outdo each other. In a perfect world about 70 miles is possible I'd guess but only line of site and I'd think a high antenna mast at that. I'd guess that at 60-70 miles with the commercial one they 60-80 percent would drop and if something were in the way it would be sporadic reception at best. Even bertha has trouble sometimes with my 62 mile station when the air is filled with heavy rain or snow.

Thanks for taking the time to share this.
resago3 years ago
when you connected to a combiner, make sure to use exact same length coax jumpers.
deceiver (author)  resago3 years ago
Resago is right. Attenuation is important in antenna's. If your signals are strong you might not notice any issues with it but if not it could make a difference. Some types of antennas particularly in radio communication have attenuators that can tune out differences. Some are even manual. Ham radio operators certainly know about this.
thanks Resago.
resago3 years ago
to further optimize your antenna, you could make a half wave balun instead of an off the shelf model, you could pick up as much as 3 db over a radio shack balun.

8" of RG-59 would do the trick.

Google half wave balun for more info.
if you don't want to solder, then just use a quad grounding bar with F-connections, and some extra center conductor pushed into the other end.
this will make sense after you Google the design.
vincent75203 years ago
I cannot make any comment on your antenna although it seems very well done …
But I would love to have a better look at your workshop : it looks like it is both beautiful and very professional and : congratulations !…
deceiver (author)  vincent75203 years ago
I've got a few pictures of the shop at Lumberjocks website here.

http://lumberjocks.com/deceiver/workshop
browsed through you pictures ; it's definitely beautiful: congratulations ! …
da winksta3 years ago
thanks for posting your project! I too am in southern maine (kennebunk) and trying to do the same thing. in Nashville I got over 40 dtv channels in my RV, we really need to catch up. Most of the towers appear to be above portland to the west. thanks again
deceiver (author)  da winksta3 years ago
Yes, In cities people hang a couple of wires on a piece of cardboard behind the TV and get 50-60 channels as they are all within a few miles of them. Not here in Maine though. My nephew lives in Southern New Hampshire and most of the stations are in Maine. This puts him out of range of most of the reception. Too bad, before, using analog signals you could get stuff from a long way's off, even Boston.

Being in Kennebunk you do have a bit of an advantage. You are closer to the ocean, Unless you are nearer the Arundel boarder you should get a flatter line of site to Portland and even the Fox station upstate a bit. It is even possible that you might get some Boston area stations as Boston is almost at sea level. You would be at a limit or over though considering the curvature of the earth. In your case, the higher the better.
Thanks for commenting.
I actually am in Arundel but east of Route 1, so almost kport. Right now we're getting 6, 8, 13, and 26, although sometimes 6 and 13 break up. This is using the coat hanger antenna with 7"X3" whiskers and no reflector. I would like to pick up at least 51, 21, and 11 to cancel my cable subscription.
Will using larger whiskers like yours give better reception? How about even bigger? I assume at some point the signal wavelength will be small enough that bigger isnt better? thanks!
deceiver (author)  da winksta3 years ago
I get 6, 8, 13, 10 +26 which are PBS (maine/NH and 23 which is Fox channel (american idol for the wife). But that's it. channel's 6,8,13 are the strongest, so much so that I can move the rotor to tune in 23 which is the hardest to get and the others are strong enough to come in without adjusting. 6 and 13 are in Portland which is close and 8 is further away but the antenna is on Mt. Washington so it's signal carries far.

I'm not sure what 51and 21 is.. is that the cable number or the actual station number? Maybe it's my pbs26 and Fox?

My design has whiskers that are one size and optimized for a range of channels that are common to hdtv signals. By having 4 of them with a reflector it multiplies and concentrates that signal. Then by doubling the antenna as a dual array it doesn't double that signal but adds significantly to it. Add to that the antenna is upsized for more reflectivity to the whiskers. I live on a lake so I'm in a vallley. I feel fortunate to have managed to tune in the channels that are available here.
With a reflector I was able to pick up 11 when I point it shouthward.

So the 9.5inch X 5.5 inch whiskers is optimal? I have four sets as well, but I just used a different design that listed 7inchX3inch instead. I will try the bigger whiskers for my next version.

hmmm 21 and 51 are listed as WPXT and WPXG, CW and ION

Where I am, the dtv.gov map says that the Fox out of sabbatus area should be stronger than the one out of boston.
deceiver (author)  da winksta3 years ago
I don't get 21 or 51 either. Both have a fairly low transmitting strength. It could be the terrain from there to my place too.
COMMODORE643 years ago
Will it makes any difference if I uses the satellite splitter rated as of 2000MHZ/3000MHZ with 300/75 OHM transformer instead of those 900MHZ one for UHF/VHF splitters?

Any difference on using RG59 and RG6U cables?
deceiver (author)  COMMODORE643 years ago
The splitter with the high rating shouldn't be a problem as they are designed to work up to 3000 mhz. They are expensive though and a lower frequency one is good enough.

You do need RG6 cable though the RG59 is generally supplied with DVD players and VHS players because it works fine in short lengths. If you're going to run a longer length from the antenna say from a roof then you should use the RG59
Cameron6573 years ago
Awesome job!!!!! The best phased array DIY guide I have ever seen. 5/5! The end result looks VERY professional and so is the performance.
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