Very Good $2.00 Homemade Antenna For HDTV

[Smith P.]

I would try to rise it up - to balcony, windows on top or temporary hang somewhere up there to see if signal will increased and appear for those 2 stations.

 

[jrp]

I finally got my antenna up off the ground and got an immediate 25+ point boost in signal strength on the channels I was receiving. In addition, all the locals broadcast from that location now come in, most with good, strong signals.

It may be ugly, but I've got a total of about $6 in it.

 

[Pepper]

jrp, would love to see some pictures of what that looks like and how you've got it mounted.

Ugly is as ugly does.. and $6 sounds beautiful to me.

 

[jrp]

jrp, would love to see some pictures of what that looks like and how you've got it mounted.

Ugly is as ugly does.. and $6 sounds beautiful to me.

Will do… but don't say I didn't warn you!

 

[jrp]

Here it is, mounted on a pair a steel fence posts (the kind used to build livestock fences for you non-country types), attached with a couple of u-bolts. I need to bury the cabling so I don't mow over it. My wife says I need to move it further from house so you can't see it from the road first.

The lumber came from scraps I had lying around, the chicken wire was used to keep rabbits out of my garden, the bowties used to do what hangers do. I had the screws, washers, staples, wire nuts and fence posts on hand.

I purchases the wire and u-bolts. The wire is 12 gauge solid and was measured so that each corresponding piece is identical in length.

The chanellmaster signal booster used to convert to the rg6 leading to my ViP622 was salvaged from the ice storm that destroyed my previous antenna, eliminating the need for 75-300 ohm converters.

 

[airops2]

Best HDTV ant. you can build

This is my first post, I've built the best HDTV ant. that I have ever tried even better than any store bought ant. I stacked two side by side thus creating a perfect replica of a DB-8. Signal strength of 100% on all of my local OTA HDTV stations in my area, tower farm is approximately 40 miles away. I've attached a PDF with the specs so that you guys can build one.

 

[mastermesh]

jrp... that double antenna looks nice... but could it work better if they were spaced further apart? I can't find the link now, but the other day I came across a website with some weird formula on it and it roughly worked out to some sort of division problem where to get channels as low as 6 or 8 you need to space antennas around 6 feet apart and to go as low as channel 3 you need to space about 8 feet apart. It was talking about up and down on the same pole I think, but I'd suspect same thing would be going on with side by side setup?... you might be causing interference from one antenna with the other?

Airops 2... I like that pdf and want to try it... but uh, are the 19.0000, 1.0000 marking and stuff inches, millimeters or something else?

 

[digiblur]

Here's one I built off of the specs from my CM4228.

 

[zzandrewst]

Here's one I built off of the specs from my CM4228.

What type of screen that you put behind the antenna?

 

[KAB]

What type of screen that you put behind the antenna?

I can't answer for Digiblur, but it kind of looks like roof flashing which is what I used to build mine.

 

[digiblur]

What type of screen that you put behind the antenna?

You are looking at the back of aluminum siding with a simple sander taken to it for a minute or two.

 

[jrp]

jrp... that double antenna looks nice... but could it work better if they were spaced further apart? I can't find the link now, but the other day I came across a website with some weird formula on it and it roughly worked out to some sort of division problem where to get channels as low as 6 or 8 you need to space antennas around 6 feet apart and to go as low as channel 3 you need to space about 8 feet apart. It was talking about up and down on the same pole I think, but I'd suspect same thing would be going on with side by side setup?... you might be causing interference from one antenna with the other?

I don't seem to be getting any interference as I'm getting 5 & 8 very well, but I can see how spacing them might be beneficial. Given my wife's reaction to the unit, however, I don't think I'd want to hear her thoughts if I split it in two. I'd like to see that formula if you find it.

I'd like to use a backing like Digi's instead of chicken wire, but mine has to be outside, so a solid back is out of the question. I do need to bury the cable, as I've mowed over it once already.

 

[zzandrewst]

You are looking at the back of aluminum siding with a simple sander taken to it for a minute or two.

I have built an antenna that I use at my beach house and I do not have a back to it. Do you think that I would notice a difference if I simply added a back to it? I built my antenna to the specs in the YouTube video on the first page of this thread. I haven't really been able to pick up much with it. Everything has lots of static in it.

 

[digiblur]

I have built an antenna that I use at my beach house and I do not have a back to it. Do you think that I would notice a difference if I simply added a back to it? I built my antenna to the specs in the YouTube video on the first page of this thread. I haven't really been able to pick up much with it. Everything has lots of static in it.

It helps with the VHF Hi side and also helps kill the backside multi-path. Basically stops the "ghost" signal bouncing back to your antenna.

Doesn't take much to see if it makes a difference, just slap a piece of cardboard wrapped in aluminum foil on the back temporarily.

 

[mastermesh]

Not where I first found it, but the formula is listed below
Stacking TV Antennas

SPACING

For optimum -performance, stacked antennas must be properly spaced. If you do not space vertically and horizontally stacked antennas more than ½ wavelength apart, they will adversely load each other. Loading is caused by the elements of one antenna re-radiating some of their received energy into the element of the other antenna, with consequent reinforcement and cancellation of fields and voltages. 0ptimum and minimum spacing is 0.94 and 0.60 wavelength, respectively, at the lowest frequency received. Spacing exceeding one wavelength reduces the performance of the stack.

In a horizontal stack in which’ the elements are tip-to-tip and the longest element is something over .6 wavelength long, the minimum practical spacing will be some distance over .6 wavelength, to prevent the longest element of one antenna from touching the tip of the corresponding element of the other antenna. Recommended spacing is 0.94 wavelength between booms at the lowest channel involved.

Because of restrictions on space (usually height), there will be times when it is impractical to space antennas a full wavelength apart. In such cases it might be necessary to reduce the spacing to something less than a wavelength, but it should never be less than .6 wavelength. No physical damage will be caused by spacings closer than one wavelength, but as spacing is reduced, performance will deteriorate. At less than .6 wavelength, all of the advantages of multiple-stacked antennas are lost.

All portions of the antenna supporting structure should be made of wood or plastic. Horizontal metallic supports act like antenna elements, absorbing and reradiating the received energy in an unpredictable manner which causes unusual voltage/frequency effects from the antenna array. Where wood supports are subjected to adverse weather, redwood or cypress lumber is recommended, for extended life.

Stacked antennas should be identical. They can be broad-band, single-band or single-channel antennas, but they must be identical. If not, the phase of the voltages from the two antennas, when combined, will not produce the optimum signal level.

http://www.anarc.org/wtfda/stagger.pdf talks about stagger stacking, and other stuff, but based on what I'm reading stagger stacks are only needed if you have two sources of tv or radio in opposite directions of one another and that is causing you interference since the one that's 180 degrees away (ie in back of where you are aiming) is causing you troubles....

anyways, that pdf mentions the formula and shows a graph on page 4 of 5...

Here's the formula:

The distance can be found by dividing the frequency, in MHz in to 11808 (to give the wavelenth in inches), and multiplying the result by 0.6 (in other words you are looking for 60% of the distance of the wavelength for optimum spacing in inches)

and if you do need stagger stacking... the formula to determine distance of in front/back stack is

1/4 wavelenth (in MHz)

 

[zzandrewst]

It helps with the VHF Hi side and also helps kill the backside multi-path. Basically stops the "ghost" signal bouncing back to your antenna.

Doesn't take much to see if it makes a difference, just slap a piece of cardboard wrapped in aluminum foil on the back temporarily.

I'll have to try the aluminum back when I go back to the beach. Thanks!

 

[Don_M]

Doesn't take much to see if it makes a difference, just slap a piece of cardboard wrapped in aluminum foil on the back temporarily.

If doing this improves things for you, one way to make it more permanent would be to swap out the foil-wrapped cardboard and attach a couple of wire cookie racks from the dollar store. (All that humidity at the beach is likely to warp the cardboard over time.) Sizes that will work are 10x20 inches or 12x20 inches. Just be sure the foil or wire reflector is 3 inches or so behind the "whiskers." I found out the reflector degrades reception if it's much closer than that. The $4 I spent on the racks was my only outlay for the antenna!

 

[avg1joe]

Just be sure the foil or wire reflector is 3 inches or so behind the "whiskers."

I noticed that signal was affected by the reflector spacing as well. I visualized an adjustable reflector mounting to fine tune this distance between the antenna elements and the back screen but haven't gotten around to making one yet. Has anyone tried fine tuning this and found the optimum spacing?

Most of the instructions give the measurement for the antenna V's as 7 inches. After doing some reading the recommended antenna length is 91% of the half wavelength. I setup a spreadsheet to calculate this and 7 inches is right for channel 59 but the wavelength increases as the channel number decreases. For channel 32, 9 1/4 inches would be better and channel 14 needs over 11 inches.

If most of your available channels are not between channel 50 and 60, can you squeeze a little more signal out by making your V's a little longer (and the wires between them)? If anyone has tried monkeying with the measurements let me know.

 

[zzandrewst]

I noticed that signal was affected by the reflector spacing as well. I visualized an adjustable reflector mounting to fine tune this distance between the antenna elements and the back screen but haven't gotten around to making one yet. Has anyone tried fine tuning this and found the optimum spacing?

Most of the instructions give the measurement for the antenna V's as 7 inches. After doing some reading the recommended antenna length is 91% of the half wavelength. I setup a spreadsheet to calculate this and 7 inches is right for channel 59 but the wavelength increases as the channel number decreases. For channel 32, 9 1/4 inches would be better and channel 14 needs over 11 inches.

If most of your available channels are not between channel 50 and 60, can you squeeze a little more signal out by making your V's a little longer (and the wires between them)? If anyone has tried monkeying with the measurements let me know.

I'm planning on making another antenna for my house and the channels that i need most are 10, 13, 15. You mentioned 7 inches as the V length, but the video says 14 inches. I'm assuming that you're saying that half of the V will be 7 inches and the other half will be 7 inches correct? Going by your formula and the middle channel of my three most watched is 13, so my Vs will need to be 11.83 inches - Does this mean that the total clothes hanger length for each V will be 23.66 inches?

 

[zzandrewst]

If doing this improves things for you, one way to make it more permanent would be to swap out the foil-wrapped cardboard and attach a couple of wire cookie racks from the dollar store. (All that humidity at the beach is likely to warp the cardboard over time.) Sizes that will work are 10x20 inches or 12x20 inches. Just be sure the foil or wire reflector is 3 inches or so behind the "whiskers." I found out the reflector degrades reception if it's much closer than that. The $4 I spent on the racks was my only outlay for the antenna!

That's a good idea about the cookie racks! I'll have to try that on the next antenna I build - and also on the one at the beach house when I get back down there. How did you connect the cookie racks to the antenna?