Introduction: Build a Large DB8 HDTV Antenna: Big Bertha

Picture of Build a Large DB8 HDTV Antenna: Big Bertha

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.


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.

Step 1: Plans and Measurements

Picture of Plans and Measurements

I want to give credit to this website for the dimensions for the antenna. And the diagrams uploaded as part of this instructable. At the site you can find a bit more information.

The measurements should be exact or as exactly as you can get them. I will describe the materials as the steps to building this occur. Most of the actual antenna construction part can be purchased at Home Depot which is where I got the raw construction materials.

The first diagram gives the overall dimensions of one array.
The second diagram shows the wiring and dimensions of the wiskers
The third diagram shows the measurements of the wiring

I suggest you print these three pages.

Step 2: Building the Reflector

Picture of Building the Reflector

The reflector can be made of any metal. You could use a solid sheet but in a big wind it would be a problem. And all that is really needed is horizontal bars or wire that are separated by no more than 2 inches vertically. Anything larger than that and it would exceed the wavelength and would not reflect the signal to the wiskers. I found some 36" wide rolls of something called galvenized wire netting at Home Depot. It's got 1/2 inch squares of stiff galvenized wire that is welded at each crosslink. The 36" is perfect for the width of the array. Wider could be used but it would go wasted as the reflected signal wouldn't hit anything useful.

Unroll 40 inches (for the hight) and cut it with snips. To reinforce the sides (40" side) I used thin 1/4" wide angled aluminum trim. I placed one side of it under the mesh and pounded it over with a hammer.

Picture 2 shows this more clearly. I then turned it over and pounded the other side to flatten the mesh as the aluminum tended to curl in the direction of pounding. Do the same thing to the other side.

4th picture
Next, use two, thick, 1inch wide X 36 inches long aluminum bar to reinforce the top and bottom. As the measurements show the two sides of the array are wings that will be slightly folded in. Place the bar in a vise and bend 10 inches of the bar 2 1/2 inches forward. Do the same to the other end. To assist, make a wedge 10 inches long and 2 1/2 inches wide out of hardboard to act as a guide. Or just measure it. Make another angled brace for the bottom of the array.

5th picture
To prepare to install the two bent top and bottom braces, measure 10 inches of the side of the mesh and bend it slightly on the edge of the workbench. Do the same to the other side.

6th picture
The bar is on the bench with a final angle check. Drill small holes. 2 on each end of the angled bend and one in the center of entire bar. I used 3/4" size 8 machine screws and nuts with washers on each side to bolt the bar to the FRONT of the mesh. Bolt one to the top and one to the bottom.

Step 3: Spline

Picture of Spline

For all the solid bracing you could use a number of materials. Wood would work but it might rot over time. I chose to use plastic board. It's the stuff they often use to do the eves of houses now. It's white, tough and work much like wood. It's also pretty expensive. It's up to you.

Cut the spline the hight of the reflector (40") and drill and bolt to the top and bottom of the BACK of the reflector. Be sure to use a washer on the spline side. I also used a small lock washer. I expect wind will rock the reflector back and forth and don't want the nuts coming loose.

The pictures below just show three views of this step.

Step 4: Preparing Forward Whisker Brace

Picture of Preparing Forward Whisker Brace

The V shaped wiskers will need to be mounted ahead of the reflector. A brace 29" long (the distance from the top to bottom wisker is 27") is made from the same material as the back brace.

Picture 1
Use a large drill (forstner bit works nicely) to drill a recess for each of the eight wiskers. use the diagrams from step two to determine the distance apart they should be. About a 1/4" deep should be enough. Notice that the recess is of the side of the brace. This is to accomodate the wiskers sticking out.

picture 2
Drill the center of the recesses to accept a machine screw.

Step 5: Preparing Phase Line and Whiskers

Picture of Preparing Phase Line and Whiskers

Phase line: the wires that connect the wiskers together. See the diagram. I used #12 copper house wire.

Whiskers: The wires that produce the V shaped elements. I splurged and purchased some bare solid copper #6 wire off the roll at home depot. I bought 30 feet of it and have about 2 feet left. I bought enough because we're building two of these things here and hooking them together. If you're only building one then 16 feet should be sufficient with a bit left over. I built two so I could connect them together and maximize my signal collection. One of these is good for 30 mile reception.

You can use smaller wire for the whiskers but it might no stay in the correct configuration over time as movement of the antenna might alter their shape.

Use the phase line diagram in step 2 to determine measurements.
I stripped the plastic of the house wire to obtain a length of plastic coated white and black copper wire. I wanted the plastic coating to stay on the wire everywhere except the place where it connected to the whiskers with a screw.

shape the two wires as shown in the diagram. Make loops where it will go under a screw. make sure the loops coincide with the depressions you drilled in the front brace. Be sure to make a loop for the center. This is where the antenna wire will connect when it is mounted on the roof.

Picture 1 and 2
I wanted the plastic insulation off the loops but cutting it off was getting tedious. So, I fired up the propane torch and melted it off. With a little sandpaper the loop came clean.

Pictures 3 and 4
Cut 8 pieces of the #6 copper wire for the wiskers. In the end each whisker should be 9 1/2" long. So cut it the wire 18". I found that an extra inch helped out. You can always cut any excess length off after.
Bend the wire in half around a bolt in a vise. and pound it together, then use pliers to spread the whiskers apart in a V shape.

Picture 5
Seat the V of the whisker in the recess, Place the phase line wire loop over it, add a screw, with washers on both sides and squeeze it in place by tightening the nut. Do the same for all 8 whiskers.

Step 6: Mounting the Whisker Spline to the Reflector

Picture of Mounting the Whisker Spline to the Reflector

The following pictures are just various views of the same thing. The whisker spline mounted to the reflector. this mounting can be accomplished many ways. You could cut pieces of plastic pipe and use it as spacers for example. I decided to use some more of the plastic board to create a fin between the splines. I thinned it out a bit on my planer (if it looks thinner to you).

It is attached to the rear and front spline with 2 inch galvanized sheetrock screws. 5 or 6 on each side. It seems solid. Be sure to notice the measurement parameters on the diagrams for how high it needs to be raised.

Also notice the whiskers have been bent forwards 2 1/2 inches to coincide with the wings of the reflector. In actuality, this thing could have been made flat. But only the reflector directly behind the whiskers would have deflected a signal to them. The bent configuration creates slightly more reflection and therefore slightly more signal to the whiskers. But not much. Remember, I'm looking for fringe signals. You may not be in that position. Stations might be closer for you.

Step 7: Ganging Two Arrays (optional)

Picture of Ganging Two Arrays (optional)

As you can see in the following pictures I created two reflectors to put them together to make an array. One reflector will work perfectly well for up to about 30 miles from a station. Two arrays won't give you double the distance but almost. And I'm counting on the design of these antennas to actually be over 30 miles for one and at least 60 miles for two.

I ganged them together using think 1" aluminum angle bar. I simply drilled and bolted them across the top and bottom of the flat bar braces. I used two screws on each side, so four screws for the top and four for the bottom.

The center of this whole thing is where my U bolts will be placed to mount to the mast pipe. If you use only one reflector then it would go in the center of that reflector.

These reflectors can also be mounted one above the other on the mast but you'd need a longer mast pipe and doing so might facilitate having to use guy wires to steady it in a wind. Alignment is fairly specific for HDTV signals. A bobbing, waving antenna might be an issue.

If you decide to just have one antenna then skip to the section on connecting them. It will be simpler.

Step 8: Connecting Your Antenna Array

Picture of Connecting Your Antenna Array

Please remember that all connection instructions are your responsibility. If you feel uncomfortable on a roof doing this or with grounding properly for lightning then have it done professionally. Basically this means that I absolve myself all responsibility in this area.

Antenna mast
How you mount your antenna is your business. There are several mounting masts available. I'm mounting mine to my chimney. Using a set of stainless straps that wrap around the chimney for just this purpose. My chimney isn't being used. If yours is, especially for wood or coal I suggest another spot. Your antenna will be soon covered with soot if you use the chimney. Two things are important.

One is that if you can get higher, the higher the better. Mine will be 10 feet above the roof. Remember though that anything much over that should have guy wires to steady it.

Secondly, if the stations are not all in one location, like a city, then you'll need an antenna rotor to turn the antenna the desired direction to the station. See the last chapter of this instructable to find out where your stations are located.

Connecting the antenna
If you just made one antenna then you'll only need the balun, lightning arrestor and coaxial cables. Connect the two leads of the balun to the too center loops of the antenna phase line. Connect with screw, nut and washers keep it loose or drill and bolt it to the standout board if you want. connect the other end to a short coaxial cable. Screw a lightning arrestor to the pipe and connect the other end of the coax to it. The other terminal on the arrestor goes to the TV or DTV converter box.

If you've got two antenna's like I do then you'll have to use to balun's and a splitter (or in this case a splitter acting as a combiner) mounted between the antennas. the diagram should explain this.

I recommend that all connections either be wrapped nicely with electrical tape, or coated with silicon II that hardens (outdoor silicon caulking is fine) or use coax with weatherproof boots on the connections.

Grounding your mast
It is very important that you ground the antenna and mast. You'll need to get a ground rod and connector made for this and a length of aluminum grounding wire. Attach the ground wire to the antenna mast with a screw or clamp and run it to the ground rod that has been driven into the ground. Securely attach it to the ground rod with a screw clamp made for this.

Step 9: Up on the Roof!

Picture of Up on the Roof!

This series of pictures just shows the assembled antenna up on the roof.

The first picture shows one of many ways it can be done. I have an unused chimney that is large and strong. I chose a chimney strap system. It consists of two corner brackets and stainless straps that go around the chimney. Turnbuckle type bolts let you tighten it. The mount is strong. You can also get roof mounts in various configurations. One of the best and least invasive are the brackets that mount on the side of a house at the peak. No holes in the roof and you can screw into solid wood.

The second picture shows one half of the array and how the matching transformer is connected. I attached the leads with stainless steel machine screws with washers on both sides and a nut. Then ran the bolt through the white plastic to brace and bolted the connection to it.

The third picture is of the splitter being used as a combiner. A coax from each elements matching transformer is connected here so they antennas can be 'combined' into one cable. This splitter actually degrades a bit of the signal but the second element will bring in enough extra signal to make it worthwhile.

The fourth picture: Bolted to the mast pipe is the coax grounding lug. The short length of coax from the splitter is on one side and the other side is the  coax to the TV.  The ground wire is connected to the lower pipe and goes to a ground rod. There is a grounding screw on the grounding lug that the ground wire can be attached to. My wire is attached to the mast below the rotor.

Here you also see my channel master rotor. Where I am the signals are within a 20 degree arc with some of them being 180 degrees to the rear.

The fifth picture shows the entire antenna from the front.

Step 10: The Visual Results

Picture of The Visual Results

The digital tv converter box I chose is the Digital Stream DSP7700P Digital Set-Top Box. There are many to choose from. Some have much better reviews than others. But, there are enough horror stories for each box to make you think that all of them will be a lemon. And at this time not many are available since the government coupon deadline is over. This one seems to be working well.

The second picture shows the back of the converter box. Simple really. Coax antenna in and coax out to TV or you can connect your TV via the analog RCA jacks. Your choice. The box has an on button and channel up/down buttons. It comes with a infrared remote that has more bells and whistles. The instructions are sequential and fairly clear. You can see a signal strength and scan for channels that lock in when done. There are full menu items for a variety of functions.

Where I live in  Southern Maine there are three locl channels NBC, ABC, and CBS that are 25-35 miles away. I live on a lake and therefore a valley that is low and surrounded by hills. Trees are also all around my house and the leaves are still on them. My antenna is about 20 feet above ground.

There are three public television stations 7-35 miles away and Fox movie station where american idol exists. So, the wife would like to get that. The only problem is that Fox is 62 miles away. Definitely a fringe station.

The closest station NBC has a signal strength of 88-90 and very strong. ABC and CBS have lower but still strong signals. ABC is further away but the antenna is atop Mt. Washington so, a good signal. Picture three shows the signal strength for NBC.

The fourth picture shows the signal strength for Fox at 62 miles away. The signal strength is 30% which is more than enough for viewing. A strength of 5-10 should be enough but with this station at least 18 is needed. With digital signals the picture is usually always good if you can see it. Snow on the screen is only for analog signals. At 18 though some blocky artifacts can sometimes be seen. This signal was supposed to be the litmus test for my antenna. My neighbor with a db4 an amplifier can't get this station.

The last picture is of the trees in the direction most of my stations need to deal with. Trees aren't good but the antenna seems to not be bothered by them. The leaves will soon be down.

Overall the construction experience has been pretty good. I had a lot of fun and learned a lot in the process. I hope the info here is correct. I'm no expert for sure. I ended up getting the three networks and Fox, three public television stations, and a couple of smaller local stations. BTW one of the good ones ABC is a VHF not UHF station. This often requires a VHF antenna. The strong signal along with the strong antenna seems to make this unnecessary. After the weekend I will be giving Cable TV back their signal.

Thanks for reading,

Step 11: Digital Signal Strength 101

Picture of Digital Signal Strength 101

There are tools on the internet to help you determine the stations in your area, their power, distance, and your chances of getting them to show on your TV.

I suggest you try 'TV Maps' link. Type in your address, height of your antenna and you can determine your chances of reception.

You'll also see a list of stations in your area. If you choose one you'll see a color coded map of signal strength from the station to your location. The list shows the distance in miles and and important number NM or noise margin. The antenna we're making should have a gain of at least 15, hopefully more. Think of the NM as the loss of the signal to your house. It could be hills, leaves, walls or weather. It's also distance and location of you and the signal tower. The goal is to get a net gain of at least 0. At zero you'll get a signal. For a reliable signal a higher number is beneficial. 5-10 means you'll probably get a signal over 0 consistantly.

So, take your antenna gain. Let's use 15 and add the NM For the positive numbers it's no problem. The negative numbers might be another issue. An antenna of 15 db hoping to get a stations that's -11 db leaves a net gain of 4. Marginal but a reliable steady signal is possible at this level. The thing is every splitter, length of cable, branch in front of the antenna, Snow in the air, and many other factors can lower the db of gain bringing that gain of 4 down to 0 or lower meaning loss of signal.


Dad shack productions (author)2017-09-11

I built two of these over the past month. I mounted them in the attic of my two story house and they work great. One is aimed at about 94 degrees and one at about 345 degrees magnetic. Additionally I added a 1/2 wave dipole element connected at the center point of the one pointed at 94 degrees. This was to pick up a VHS station about 25 miles away. I went from 6 channels to 30 channels. All of them solid. The VHS channel makes 31. The furthest channel I get clearly with no pixelation is 65 miles away. I spent about $75 in materials for the two of them. Thanks for providing such well developed instructions. It was a really enjoyable project and advances my cord cutting efforts.

Glad it worked out good. Glad to hear my design was of help. Ours is still going strong after many years. And it's out doors. If your attic has some height to it then your reception will be even better. Thanks for commenting

TheBrokeHobbist (author)2017-04-03

You said you added an amp. what did you use?

deceiver (author)TheBrokeHobbist2017-04-04

I'm not sure the brand it was long ago. It's mounted up there on the mast and it derives power from the existing coax cable by connecting a power supply to it from inside the house at the TV.

ChannelDB8 (author)2017-02-20

Hello Author. Thanks for the detailed instruction, we now have Attic installed DB8 Antenna, getting 81 channels of which 17 are HD :).

Prior to embarking on this DIY antenna, my adventure took 3 months in total, tried 5 different off the shelf antenna's, thanks to Amazon, and returned them. They all had some or the other channels missing or reception were spotty (pixelation). At best i could get 32 channels with these indoor antennas.
With the custom made, i now have good reception for almost all channels. Am yet to encounter pixelation!
I would like to thank you for the detailed tutorial, followed it word to word, material to material. Only change was for the reflector screen, used EVERBILT 1/4 inch 23 gauge galvanized Hardware Cloth found at Home Depot.

DanielG64 (author)ChannelDB82017-02-20

So pleased. Mine is still going strong on my house in Maine. Lots of weather and it hasn't suffered at all. Amazing results. Way to go. You should include a picture of it!

ChannelDB8 made it! (author)DanielG642017-02-26

Hi Dan. Here are the pics. My house is about 28.5 miles from the tower in San Francisco, CA. As you can see great HD results. I cannot tell you how happy i am with the quality. I've new found craze to watch TV after building the antenna :).

gunguru (author)2016-01-19

I don't know a single thing aboot TV antennas but, this one works like mad!! I just finished one as per this ible. I used wood on the supports and steel for the mesh bows. I haven't even had a chance to do the lightning protection yet. I'm in a signal hole and have never been able to get any indoor antennas to work. I built this one because of the positive responses and the fact that outdoor antennas are so expensive (plus they really can't guarantee that they will work)!! Thank you for posting this! I am aboot 40 miles from Atlanta, Georgia and am now getting 51 channels (some are radio stations???) whereas before I could only pickup 3 clear enough to watch!! Awesomeness!!

deceiver (author)gunguru2016-01-19

Ha! I happy for you. 40 miles and that may channels. Who needs cable?

gunguru (author)deceiver2016-01-19

Scratch that? I moved the antenna and rescanned for channels this morning. Now I have 63 channels (4 of those are radio stations???) Now I'm thinking aboot using the leftovers to build another to face west for getting Alabama channels! The only question I have is ....... could this pick up farther channels with an amplifier of any kind? I saw one at Lowes for like 12 bucks. I live in an off-grid tiny home so this was very exciting for us! Next, I want a wifi antenna so I can watch netflix without using data on my phone! []

deceiver (author)gunguru2016-01-19

Consider installing an antenna rotator instead of building an entirely new antenna. It should be less espensive. I have an amplifier installed but only because one of my stations is 64 miles away. It comes in either way but sometimes drops off in heavy rain or snow. This helps. You should use the tool at the bottom of my instructable to see if there are any further stations within shooting range of your antenna. An amplifier might not do any good beyond what you're getting in now.

gunguru (author)deceiver2016-01-21

Thanks for replying. I may give that a try.

gunguru (author)gunguru2016-01-21

By the way, I have made several believers out this in the past two days. People can't believe that I am getting so many air channels with this thing. I have directed everyone to your instructable to build one for themselves. Some have even said that they would drop cable or satellite in favor of this to save 150 bucks a month!

gunguru (author)gunguru2016-01-21

I am also a guest speaker at a tinyhouse jamboree in March and plan on showing this to everyone there! Awesome!

deceiver (author)gunguru2016-01-21

I don't live in a tiny house... but not a really big one.. I am a fan of small trailers though. I used to have a teardrop and since then I've converted a 14 foot cargo trailer. Looks like a small motel room inside.

As far as dropping cable.... Long ago, when I built the antenna I cut cable tv and kept the internet. I upped my subscription to a little higher level to get a faster connection. My daughter subscribes to Amazon and shares her subscription with me and I we do the same with her regarding Netflix. I purchased a mac mini which connects directly to hdmi on the tv... (we got a 60" sony btw) and I use a program called vuze to download virtually anything I want. I also subscribed to a VPN (very private network) to protect myself. It reroutes my ip address via Switzerland so no tracing.

All in all I have local channels with the antenna, other movies/tv via amazon and netfix. And anything that has pretty much played at the movies or on tv from last night to forever via the computer. Sometimes I can even watch movies that are in the theater or haven't even come out yet. Yep, I guess my scruples are in a shambles but I get good entertainment.

gunguru (author)deceiver2016-01-21

I would like to swipe wifi from our library down the road. Its about 2 miles away so an antenna is needed. We are off grid so we have to work harder for creature comforts. Plus, not having bills is a lot easier on the wallet!:-)

MichaelG498 (author)gunguru2017-02-23
If you're still trying to build a Wi-Fi antenna, you should check out this YouTube video from kipkay. I built one a few months ago and I'm picking up Wi-Fi from McDonald's about three miles away.

JWSmythe (author)gunguru2016-06-02

You need to do a little more reading. Specifically, the frequency ranges. Broadcast TV in the US ranges from 54 to 890 MHz.

Wifi is generally 2412 to 2484 MHz and 4915 to 5825 MHz. It's usually written as 2.4 GHz and 5 GHz.

Higher frequencies mean smaller wavelengths. In the antenna design, that will mean that you will use a much smaller antenna. So the long whiskers on this antenna would be much shorter. On the back, you would want more like 1/2" holes. The overall size will be much smaller.

Wifi is also much lower power than broadcast TV, so you will need to increase the gain. Some people really like the enclosed yagi antennas (i.e., "cantenna"). I like parabolic mesh antennas. I have set up links that went many miles with relatively cheap gear. It really helps to be in control of both ends, so you can use directional antennas for the link.

... and ...

Don't steal wifi. It's illegal. It may seem ok at the time, but you won't like what happens when people start throwing around phrases like "unauthorized access of a computer network". Just because you are a little farther away doesn't mean you can't be found.

deceiver (author)gunguru2016-01-22

Not that I would promote such a thing but that would be difficult. It's not a matter of having an antenna that could pick it up, it's that the signal would never get to the antenna to be picked up. wifi can be boosted and an antenna built to directionally send it to a certain place but they'd have to do that in order for you to receive it. It would be like you trying to make a TV antenna that is designed to receive a signal 50 miles away if the station is only transmitting a maximum of 20 miles and not in your direction.

DolboD (author)deceiver2016-01-23

Meh, I don't know what he gets but reality is the same. Most over the air channels are junk just as the cable. But at least with cable you can get popular networks like Fox, CNN, Discovery, Animal planet, History channel, Comedy, Cartoon Network, TNT, ESPN, other sports networks etc etc. Yes you can get great picture quality and great satisfaction of the diy job. But honestly, no good content. Apart from 3-4 affiliated channels like Fox, NBC, ABC, you get local news, a bunch of low res weather channels, church TV and some old low res movie channels. That's my experience anyway. This whole cutting the cord thing is not that easy.

deceiver (author)DolboD2016-01-24

That's true, but like you said, most of the air channels are as junk as cable so why pay through the nose for cable then? An antenna gives you minimal junk for nothing. Cable or dish gives you maximum junk for a high cost. Why pay for junk. That's the reason we opt for cable cutting.

Like I said in another post. My entertainment consists of the antenna, shared subscriptions with relatives for netflix and amazon and a Mac mini connected to directly to the tv where I download Anything that played on any channel from last night and any movie I want. Yes, the computer cost me about a year of cable but I'm on my third year with it now. Not counting internet cost which we all have anyway, My entertainment bill, which includs everything anyone else gets is $7.99/month

DolboD (author)deceiver2016-01-23

Meh, I don't know what he gets but reality is the same. Most over the air channels are junk just as the cable. But at least with cable you can get popular networks like Fox, CNN, Discovery, Animal planet, History channel, Comedy, Cartoon Network, TNT, ESPN, other sports networks etc etc. Yes you can get great picture quality and great satisfaction of the diy job. But honestly, no good content. Apart from 3-4 affiliated channels like Fox, NBC, ABC, you get local news, a bunch of low res weather channels, church TV and some old low res movie channels. That's my experience anyway. This whole cutting the cord thing is not that easy.

cwilly8 (author)2016-12-10

Can I ask your opinion about our installation needs? This will be an indoor-mounted antenna. From our location, we are about 60 miles from Chattanooga and Knoxville, TN, and they are about 110 degrees apart in direction. Both cities have the three major networks, so we probably don't need to get both simultaneously. From, all show a 2Edge path with signals of -75 to -90 dBm. Should I build an 8-bay antenna for this? Thanks!

deceiver (author)cwilly82016-12-10

That probably wouldn't help much. You'd get small gain for your trouble. Your best bet is to go for height if you can. 5-10 ft can make a difference. You might need a few support wires though. Then after you get it up, check which direction gets you the best reception. Maybe one direction has lower elevation or fewer trees to go through. Trees and leaves though usually don't matter till they get wet or full of snow.

cwilly8 (author)deceiver2016-12-11

Thanks for the great info on this page, and for keeping it going!

cwilly8 (author)cwilly82017-01-11

The antenna has been built. Now I have found that someone (probably DirecTV installer) has cut or hidden the coax from the area where I was going to place the antenna. So I ordered an inexpensive wire tracer to help locate it. I'll keep you posted.

cwilly8 (author)2016-12-10

For the whiskers, can I use pieces from our old rooftop antenna?

deceiver (author)cwilly82016-12-10

Yes you can. It will work fine.

Beh57 (author)2016-11-28

What is the distance between the wisker mount and the reflector?

deceiver (author)Beh572016-11-28

The distance doesn't matter much but it's about 3"

jadams6831 (author)2016-03-27

can I use expanded galv. metal as a reflector screen it has 5/16 spacing with 3/16 strips

deceiver (author)jadams68312016-03-27

I think so. Anything that will be stable and have 1" or less spacing will do.

deceiver (author)2016-03-26

Actually you can save some time and cash by using the website at the end of my instructable to find out where all the usable stations are for you. If all the stations that you'll be able to get are in one direction why build more than one?

The other issue is that you'd have to use a combiner/splitter to joint four antennas. Every time you use a combiner you lose some signal. If some signals are weaker then you might lose them.

This is what happened to me. All my stations were in one direction and they were strong, no problem. One fringe station was about 5 degrees to the left. It was weak and only worked when pointed right in that direction. Since all other staions were strong, I pointed it at the weak station and got it and all the stronger stations in. I never use the rotor now.

VicA5 (author)2016-02-22

Looking at plans to build this and I have a question. What would your recommendation be for grounding. I remember back in the day my father would disconnect everything from the TV during storms.

SevN (author)2016-02-18

Is there any reason the height could not be doubled to create 2 6 bay antenna's?

All my reception is edge 2 due to local geography. Right now I am getting 100% signal on some local towers that are 4.9 and 7 miles away.
I also do get some very good fringe reception at 100 miles out right now.
I am however sure that is due to change once the leaves are back on the trees. I have currently been testing with an old Realistic antenna.

Currently I have been looking into the Antennacraft HD-1850 and the Winegard HD8200U. I figured deep fringe antenna's with their large surface area would would increase my chances of consistent reception.

Sounds like building the equivelent of a DB16 would be cheaper than buying a new DB8e. It might be over kill. However you cant beat surface area.

biteme_tx (author)2016-02-16

Excellent instructions and detail! I built a single 4-bay antenna using your instructions, out of scrap lumber, coat hangers and leftover Romex, just to test things out (cost me all of $2.50, for the balun). Wanted to share my experience, and ask a question.

I should first admit that there are 7 transmitter towers all located very close together, about 11 miles south of me, and that's all I care to pick up. 11-mile haul from high-powered transmitters is certainly not a "fringe" location by any stretch of the imagination. However-- I live in a 2-year old 1-story home that's built like a Faraday cage (Low-E 3 windows, radiant barrier roof decking, foil-backed rigid sheathing in all exterior walls, etc.)! And it's an urban location, so erecting a tower, or even a sizable mast is not going to win me any friends at the HOA picnic...

So I built the 4-bay antenna on the quick-n-cheap... I didn't even bother with the reflector for the baseline test, though I know it will make a large difference in the gain. I tested it inside my house, at ground level, and the results were awe-inspiring. I was able to get rock solid signal on 20+ channels from all our local broadcasters! Only the PBS station was flaky at times. :)

Now I'm ready to build the long term antenna for attic mount. I have a question for you about your design. I've seen a few other designs of 8-bay antennas, and most others directly cross-connect the phase lines of the two 4-bay assemblies. Your design, by contrast, suggests using two baluns (1 for each 4-bay assembly) and a coupler. I'm wondering which strategy to go with. Do you know whether there is a significant difference, and if so, can you explain why it matters? I'm not well-versed on antenna theory, so I'm really just looking for advice from someone who knows more than me. :)

dpatterson13 (author)2016-02-05

As soon as the weather breaks I'm going to be taking down and bringing home a 28' tower, Big Bertha will be the first to rise and reside there. It is probably 65 miles to the nearest city broadcasting signals, that had me reluctant to purchase a $200 HD antenna, but I'll gladly build this one. Thank you!
(After reading all the positive feedback, I actually think I'll be plesantly surprised by the number of channels available. Even if my reception proves to be spotty at best, it'll be fun, basically free of cost to build, and the result of my handiwork. Those are good things and all are made possible through your wonderful Instructable, Thanks again!)

deceiver (author)dpatterson132016-02-05

28 feet! Nothing helps like height. You'll be surprised at what even 10 feet can do.

Verada_Blue (author)2016-01-18

Hi deceiver read up on the phased array. Its also known as a Collinear or Panel antenna. Unlike a Yagi-Udi beam it uses a full wave not a halve wave like a dipole. So lengths are doubled which works out that your antenna at 9.5 inches is closely tuned to receive 591.150MHz as its best frequency. But other things like the reflector can alter this slightly. Love learning about this stuff. I know a lot of people are saying who cares, it works that's all that matters but some people like to change antennas to suite their area or may even want to use the same design on a scanner radio receiver so it's nice to know what makes it tick. Cheers all.

arrangements collinear arrays. Elements are

Wavelength Long (each side so this means the full width of both is a Full
wavelength).and spaced 1/2 Wavelength from each other set.

should be 5% longer than the wavelength.

The front
Elements or Whiskers should be 0.2 of the wavelength distance from the back reflector.

Verada_Blue (author)2016-01-16

Hi all, Just some advice, we all think stainless is the best
for connection if we can afford it but be aware that stainless and aluminum can
have electrolysis if put together. Try to keep water away from where they
contact each other some how. I can tell by the positive comments that the
antenna works but can someone explain how the 19cm was worked out for the
elements. Dipole antennas are half wave. This is 4 dipole antennas stacked on
top each other per side of bigbirtha and the 4 elements phase connected to make
it more directional. Each whisker should be a quarter wave. So at 600MHz the
size of the whisker or element should be close to 12cm.19cm is more for 375MHz. I’m not saying 19cm is wrong I just want
someone to explain why its so. Maybe it is 5/8 wave or ,64 wave the antenna
designer used? Or maybe your TV band close to 400MHz where you live. Thanks all and Thanks Deceiver for putting this antenna up for people to see and Thanks for answering peoples questions.

deceiver (author)Verada_Blue2016-01-17

Aluminum will react to any metal. Galvanized is actually best when used with it. Stainless is better than plain steel. This antenna uses stainless in areas that usually are structural and it's not load bearing. I figure the connections should last whatever life I want out of the unit using stainless on aluminum. At least the fittings won't rust.

As far as the whisker length and frequencies. I've always admitted that I am no expert. Far, far from it. So, I can't really comment, and make much sense, regarding the math. If you google 'whisker length UHF antennas' you'll find reference to antennas of multiple bays and wide configurations. All the whiskers are 9.5-9.75" in length.

Verada_Blue (author)deceiver2016-01-18

Thanks Deceiver, I am more curious than knocking the whisker length. I know you have been very humble about the antenna and not tried to make out you knew all. I was looking for you or anyone that read my comment one day to teach me something about the long length of the whiskers. I will check the web page you have given me. I have made lots of Yagi Udi antennas and are wanting to try a phased array like yours but until I know why the whiskers are oversize I can't adjust it to my frequency. I love building antennas and trying to get channels that normally people cant receive. It's challenge and a lot like fishing, you just don't know what you may get. Thanks for replying so fast.

Verada_Blue (author)2016-01-17

Sorry don't know how 19cm was in my thoughts when it's 9.5 Inches which is 24.13cm for the element which makes it 295MHz. I'm very curious how this size of 24 cm was worked out because I want to make an antenna the same as big birtha but for a different frequency and would like to know the way big birtha element size was worked out because using the normal way its wrong. It's unusual to use element size more than quarter wave per side because quarter wave is 75 ohm impedance per dipole so if the designer has gone for half wave on each side or 5/8, .64 wave then the impedance would be way out and yet this antenna is 75 Ohm times 4. Thanks

RyanS68 (author)2015-10-01

I made two of these antenna's from two different instructions but with different length whiskers. My first has 7" whiskers and the other 10" whiskers. The 7" one on good days picks up channels 5 all the way up to 66, bad days, no channel 5 and blocky channel 7. The 10" antenna on good days picks up channel 2 up to channel 45. I experimented with both together and got all the channels nice and clear.

I'm experimenting with making an antenna with different length whiskers, 7", 8", 9" & 10" on one post. I interchanged out whiskers. I got all the channels 2 up through 66 with the one antenna but many were going blocky on the high and low ends. My theory worked...for the most part, but could be the spacing or too few whiskers of one particular length.

Have you any thoughts of what I am attempting with varying whisker lengths as far as spacing or how they should be ordered. I have short on one end up to the long on the opposite.

With channel 2 a longer wave length, what I am trying to do is have a set to pick up the longer wave length channels 2 up to 11 and then a set that will tune in well 11 up to 30, a set that will tune into 30 up to 50 and a set to tune into 50 up to 66.

I see plans for 7", 8" and 9 1/2" but I don't think one length can really get the whole spectrum of channels clear. Your antenna, I assume gets all the lower channels but won't do well for 50 on up. 8" might get the entire spectrum on a good day but channels 2 and 66 on windy days most likely won't come in. My 7" gets all the high channels really well and on bad days, channels 9 on up will come in.

So the challenge is to make one antenna that has whisker lengths to pick up the entire spectrum of channels on bad days. I would be happy to hear any thoughts of even something you'd like to experiment with.

I'm approximately 35 miles west of Chicago from the TV broadcasting towers.

deceiver (author)RyanS682015-10-02

Hmm.... It all sounds like interesting experimentation but unless a channel is broadcasting at very low power or there are blockages between you and them then at 35 miles all channels should come in fairly clearly with the standard antenna. 35 miles isn't that far for a standard house mounted antenna. I wonder why you're finding such discrepancy between different designs.

RyanS68 (author)deceiver2015-10-05

Ok, so I ran many more experiments including building an antenna with whiskers closer to the 1/2, 1/8 and 1/16 wave lengths of the spectrum of channels. Oddly, I was getting some and not others at all and many were flaking out. I connected my two current antennas and my new one together and every different configuration was having different channels coming in clear, some flaky and others not at all. I had channels coming in I had no idea where they were coming from that never showed up before.

I duct taped my first two antennas, made like yours, on top of each other and hung them in a different spot in the attic. I got most all the usual channels except I just wasn't getting all the way down to channel 2. Channel 2 is CBS and I wanted to get down to that one. I was getting almost outdoor rooftop reception inside my attic. I was planning to build a more weather resistant antenna and put it outside.

I then decided to make a Gray Hoverman antenna. took a couple hours. I taped it to the back of a big piece of cardboard and hung it in the attic for a quick test. I amazingly got channel 2 clear but 50 was flaky. I also have odd channels being picked up but not good.

I hooked all three antennas to go into the TV and now I'm getting ALL the main channels plus a couple odd ones, in a different direction than the way my antennas are pointed.

The first picture is the Hoverman, wires taped to the piece of cardboard. My octopus attic duct work (I didn't put in and is a bad idea (don't do this)) is acting a little like a reflector for the antennas. The second picture shows the two like yours taped together. Works perfectly fine like this.

I think I'm happy for now. I have everything I was trying to pick up with the antennas in the attic and don't have to worry about proper outdoor grounding.

deceiver (author)RyanS682015-10-06

I don't know what to say... you've got a lot of reflectors or signal blockers up there in duct work and foil. Do what works I guess.

mitch12967 (author)2015-09-15

i also have a 2nd question i have a bunch of shorter pieces of 1/4" copper tubing that isnt really long enough for anything else would this also work for the wiskers or would that be to thick

mitch12967 (author)2015-09-15

would enlarging the antenna , would it enlarge its range or are these idea dimensions.

Msgough88 (author)2015-08-25

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

About This Instructable




Bio: Retired Jr. High teacher of 30 years. Always into lots of things. Now I seem to be into them more. Love woodworking, guitar, portrait painting ... More »
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