DIY Antenna

[Steven Johns]

I'm considering making this tomorrow (since its 12:37am where i'm at right now lol) but it seems there's room for improvement on the design, anybody got any adjustments to this design they'd like to point out?

One adjustment I wanted to ask you guys about was whether or not 0=<0.5 oxygen free speaker cable (5mm, the kind you use to connect subwoofers to an amplifier) is possible to use instead of the two steel wires that the balun connects to?

Regards,

Steven Johns

[ceminess]

Correct me if I'm wrong but,

Whats the point? Its using a UHF/VHF transformer, which means its not digital, which means if your in the US then it will only be good for you for a couple of weeks, then it will be useless. Right?

NVM I'm dumb, this would still work. If I didn't have satellite w/local channels I would definitely build it.

I would prolly use something other then wood to connect it too. to make it look a little better, maybe try to rig up a plastic case?

I know the speaker wire will conduct the signal fine, but I'm not sure if it would affect the signal quality if you used it.

Edited May 31, 2009 by ceminess

[Steven Johns]

The second one.

[ceminess]

The second one.

Yeah I realized I was wrong, forgive me I've been working the past 12 hours. :sleep:

[gollux]

six element hairpin

4 - bay bowtie antenna <- what you're attempting to make

12 ga copper electrical house wiring is probably the best, with 4 ga ground bonding wire for the elements. At the frequencies this antenna picks up, large diameter gives you large surface area which is where the signal travels. Anything over 1 MHz travels on the outer surface of the wire. If you really are worried about resistance, you will silver plate it and then wax that to keep it from tarnishing. Solder the elements to the wire array that connects them for best signal transfer.

Commercial antennas usually have the elements made of aluminum tubing and the matching array (wires connecting the elements) made of thick aluminum wire.

The garbage iron that coathangers are made of is kind of junk, and really pretty poor for VHF/UHF signal work, but will work fine if you're within 10 miles of the transmitter.

[Steven Johns]

Well, I made it with 2 sets of 5 iron thingys, didn't work very good at all.

Is there a major difference between the 6 element hairpin and 4 bay bow tie?

Any way I can improve the quality?

I'm gonna stick it outside tomorrow and see if that helps.

[gollux]

Well, I made it with 2 sets of 5 iron thingys, didn't work very good at all.

Is there a major difference between the 6 element hairpin and 4 bay bow tie?

Any way I can improve the quality?

I'm gonna stick it outside tomorrow and see if that helps.

Theoretically, the more elements you get out there, the more gain you get, so the 4 bay/8 element antenna should be better than the 6 element.

Make sure all the measurements are correct, the connections between the elements (hairpin shaped pieces) and the matching array (the wires that crisscross to connect the elements) are clean and solid and that the matching array (the wires that crisscross to connect the elements) doesn't touch where the wires cross. This is a directional antenna so the wood piece shown should be mounted vertically. You then rotate the antenna around its vertical axis till you get best signal.

This should be a reasonably good antenna if you are within 10-15 miles line of sight from the transmitter antenna (no hills in the way). At UHF frequencies, mount it near a window facing the transmitter antenna, or outside under the eave (it's not very weather resistant).

[Rob2687]

People have done the math behind these antennas and come up with the ideal specs for this design. The designs are all open sourced or something like that.

http://www.digitalhome.ca/forum/forumdisplay.php?f=186

I built one myself. It works quite well.

[Steven Johns]

Well I placed it outside. Standing vertically I get almost no reception regardless of which direction it's aimed at (i live on the bottom of a U shaped apartment complex, there is 3 floors of re-enforced concrete in every direction) so I laid it flat on it's back and bingo, I get every single channel except for Channel 7 (for those who live in Australia). Channel 7 came out as unknown in the converter box and has little to no reception.

I'm gonna replace the iron elements with steel ones from the hardware store, and maybe replace the timber with a much thinner clear plastic then see how I can make it look a bit nicer with a soldering iron and sand paper.

Any suggestions on how to amplify the signal? I attempted to use tin foil but I'm more interested in a way to electronically amplify it.

Also gollux, when I asked about the bow-tie vs hair pin I meant the actual design of the crisscrossing, does it really matter as to how I connect it? Would a parallel connection to the elements provide better connection than a series?

Is stainless steel as efficient as normal steel?

You said that the more elements there is, the stronger the signal. Is two layers of two pairs of 5 (20 all up) pushing it?

If I do attempt to make a weather cover for it, what material do you suggest that wouldn't interfere with the reception I get?

My bad for all the questions, but each one teach one I guess.

I'll have pictures of the final product in a couple weeks since I'm just about to hit exams.

[+StevoFC MVC]

If you are buying all this stuff to build an antenna why not just buy one already made? lol

[Steven Johns]

Eh it's going to be made as a learning exercise more than anything.

I mean, I'd appreciate the thing a lot more if I built it myself.

[gollux]

Well I placed it outside. Standing vertically I get almost no reception regardless of which direction it's aimed at (i live on the bottom of a U shaped apartment complex, there is 3 floors of re-enforced concrete in every direction) so I laid it flat on it's back and bingo, I get every single channel except for Channel 7 (for those who live in Australia). Channel 7 came out as unknown in the converter box and has little to no reception.

The vertical orientation is known as broadside, you've managed to discover the other which is end fired. This is all dependent on spacing and element length as compared to the wavelength of the signal you're trying to receive. If all the elements are connected properly, this doesn't matter at all, it's just a matter of how you mount the antenna.

I'm gonna replace the iron elements with steel ones from the hardware store, and maybe replace the timber with a much thinner clear plastic then see how I can make it look a bit nicer with a soldering iron and sand paper.

Any suggestions on how to amplify the signal? I attempted to use tin foil but I'm more interested in a way to electronically amplify it.

Also gollux, when I asked about the bow-tie vs hair pin I meant the actual design of the crisscrossing, does it really matter as to how I connect it? Would a parallel connection to the elements provide better connection than a series?

That criss-cross that's used to connect the elements is necessary because it keeps the phase relationship of the received signal matched between each pair of elements. Explaining why delves a little deeper into antenna theory than I have researched.

Is stainless steel as efficient as normal steel?

Stainless steel if properly electrically connected together is a far better material as it doesn't rust. Anything that destroys the conductivity in the surface of the material creates resistance. Radio frequency currents actually travel on the outer surface of conductors. For marine environments, it's a must. For commercial antennas, anodized aluminum is the standard. It's a lot less expensive and the oxide layer protects the aluminum from most corrosion, unless you live where acid rain is a problem.

You said that the more elements there is, the stronger the signal. Is two layers of two pairs of 5 (20 all up) pushing it?

If I do attempt to make a weather cover for it, what material do you suggest that wouldn't interfere with the reception I get?

My bad for all the questions, but each one teach one I guess.

I'll have pictures of the final product in a couple weeks since I'm just about to hit exams.

I've seen 16 element commercial versions for fringe reception. Somewhere along the line, more elements are met with the law of diminishing returns, so that seems to be the cutoff point.

[Steven Johns]

I see.

I purchased the materials (the plastic, stainless steel, bolts/nuts).

I own one of these signal boosters

My question on it is if i remove the rabbit ears, and instead attach leads to my antenna, would it amplify the signal as normal?

Do you recommend it?

The reason i asked about the difference between the array in the video i showed you and the tutorial you linked me to is that the video tells me to connect it as

X

||

X

(crossing over at the beginning and end only)

where as the tutorial tells me to connect it as

X

X

X

(crossing over after every bay)

EDIT: Also, does it matter if the elements are flat or should they be raised at an angle from where they are screwed onto the timber.

Edited June 6, 2009 by Steven Johns

[I am Reid]

My antenna:

1 6ft coax cable

1 pair of scissors

1 thumb tack

Directions: Take 1 end of the coax cable, and cut it off so its just a bare wire without the connector. Now take those same scissors and strip back to expose enough of the copper so you can make a small hook. Take the thumb tack and press it into the wall above your tv. Plug the uncut end of the coax cable into your tv's atsc tuner. Then take the other end and hang it from the thumb tack you pushed into the wall, or just let it lay on the ground, works just as good either way.

You people make this stuff way to complicated, this isnt some new fancy 2030 tech here, its the same stuff that has been around since the 1930's, just because its HD doesn?t mean you need to buy something special. You can stick a clothes hanger in there and it will work just the same.

[giantpotato]

My antenna:

1 6ft coax cable

1 pair of scissors

1 thumb tack

Directions: Take 1 end of the coax cable, and cut it off so its just a bare wire without the connector. Now take those same scissors and strip back to expose enough of the copper so you can make a small hook. Take the thumb tack and press it into the wall above your tv. Plug the uncut end of the coax cable into your tv's atsc tuner. Then take the other end and hang it from the thumb tack you pushed into the wall, or just let it lay on the ground, works just as good either way.

You people make this stuff way to complicated, this isnt some new fancy 2030 tech here, its the same stuff that has been around since the 1930's, just because its HD doesn?t mean you need to buy something special. You can stick a clothes hanger in there and it will work just the same.

Maybe it's just me, but I wouldn't use a shielded cable as an antenn;);)

[Another Canuck]

My antenna:

1 6ft coax cable

1 pair of scissors

1 thumb tack

Directions: Take 1 end of the coax cable, and cut it off so its just a bare wire without the connector. Now take those same scissors and strip back to expose enough of the copper so you can make a small hook. Take the thumb tack and press it into the wall above your tv. Plug the uncut end of the coax cable into your tv's atsc tuner. Then take the other end and hang it from the thumb tack you pushed into the wall, or just let it lay on the ground, works just as good either way.

You people make this stuff way to complicated, this isnt some new fancy 2030 tech here, its the same stuff that has been around since the 1930's, just because its HD doesn?t mean you need to buy something special. You can stick a clothes hanger in there and it will work just the same.

Regardless of what year it is, using a proper antenna will work much better than a single wire or a coat hanger.

I have three different antennas here. One is a small telescopic antenna, a classic set of bunny ears and an amplified set of bunny ears. The first picks up about 2 stations, the second, 5, and the last 20.

It's also very dependent on location. You can't use the same antenna everywhere you go and expect the same results. Heck, if I just move my antenna to the other side of the house, I lose 4 channels.

I'm sure that antenna you made works, but a proper antenna would work much better.

[Denis W. Veteran]

Sorry for the bump, but I didn't want to start a new thread.

I just built the exact same thing this past evening and it works pretty well. We already have an existing HDTV box from Rogers, and a regular SD box. I wanted to get the HD CBC and CTV channels without paying up for a second box, and this was the solution.

Before building this ugly contraption I tried old style bunny ear antennas, with limited success (signal was pretty weak for CTV).

My only issue is sometimes the CTV DTV channel creates an echoing effect - this I can easily fix by switching back and forth between channels. I don't get this echo effect for CBC.

I'm sure I can get more channels by buying a proper antenna, but those are more than $79.

[Fred Derf Veteran]

Sorry for the bump, but I didn't want to start a new thread.

I just built the exact same thing this past evening and it works pretty well. We already have an existing HDTV box from Rogers, and a regular SD box. I wanted to get the HD CBC and CTV channels without paying up for a second box, and this was the solution.

Before building this ugly contraption I tried old style bunny ear antennas, with limited success (signal was pretty weak for CTV).

My only issue is sometimes the CTV DTV channel creates an echoing effect - this I can easily fix by switching back and forth between channels. I don't get this echo effect for CBC.

I'm sure I can get more channels by buying a proper antenna, but those are more than $79.

Rabbit/Bunny Ears are VHF antennas (channels 2 to 13). You want a UHF antenna (often just a simple loop). What you built would have been a fancier version of the UHF loop antenna.

Edit: While it may show up as channel 5, the HD version of CBC is actually channel 20-1.

[Denis W. Veteran]

Rabbit/Bunny Ears are VHF antennas (channels 2 to 13). You want a UHF antenna (often just a simple loop). What you built would have been a fancier version of the UHF loop antenna.

Edit: While it may show up as channel 5, the HD version of CBC is actually channel 20-1.

Interesting. CBC does show up as 5-1 on my set.

Also, apparently both CBC and CTV broadcast from the CN Tower, but for me CBC's signal is stronger than CTV's.

[Another Canuck]

Interesting. CBC does show up as 5-1 on my set.

Also, apparently both CBC and CTV broadcast from the CN Tower, but for me CBC's signal is stronger than CTV's.

Yep, not all stations broadcast with the same amount of power. CBC's signal is definitely the strongest coming off the CN tower. CTV is actually fairly weak.

Above you mentioned the price of antennas, but when you think about it, it's a great investment. You get crystal-clear, uncompressed HD right from the source for Free.

I have this antenna: http://overtheair.saveandreplay.com/Antennas_Direct_Clearstream_Convertable.asp

And with it, I pick up...

2.1 - NBC [HD]

2.2 - NBC Sports

2.3 - RTV

4.1 - CBS [HD]

5.1 - CBC [HD]

7.1 - ABC [HD]

9.1 - CTV [HD]

11.1 - CHCH [HD]

17.1 - PBS [HD]

17.2 - PBS

17.3 - PBS Kids

23.1 - CW23 [HD]

25.1 - SRC [HD]

29.1 - Fox [HD]

36.1 - CTS

44.1 - Omni 1 [HD]

57.1 - CityTV [HD]

64.1 - Omni 2 [HD]

66.1 - Sun TV [HD]

See what I mean by great investment? :p With that said, I'm in a fairly decent location, almost exactly 90 degrees between the CN Tower and all of the stations broadcasting out of Buffalo. So your results may vary.

Save and Replay is a great store to to buy OTA equipment from. I highly recommend them (Y)

If you want a rough estimate of the stations you'd be able to pick up in your location, fill in your info on this page and it spits out a surprisingly accurate listing: http://www.tvfool.com/?option=com_wrapper&Itemid=29 (be sure to select "Digital Only" on the results page).

[Denis W. Veteran]

Thanks for the recommendation. :) I might just grab one, since we're planning on buying yet another HDTV soon. Instead of feeding it just basic cable I could split the signal between basic cable and an antenna.

I'm located close to the CFTO studios. My house faces south, likewise my antenna does so as well.

This is what I get for channels:

[I am Reid]

I took a standard 6ft coax cable, stripped off the last 2-3 inches on one end. I then connected the uncut end to my tv like normal, next I placed a thumbtack in my wall. I made a little hook out of the exposed end and hang it from the thumbtack and get good signal from all the local channels. I would tell you how much it cost, but I didnt even buy the coax cable.

[Fred Derf Veteran]

Interesting. CBC does show up as 5-1 on my set.

Also, apparently both CBC and CTV broadcast from the CN Tower, but for me CBC's signal is stronger than CTV's.

CBC is at the top of the chart that you posted:

http://localhostr.com/files/d217f0/Channels.png

It comes in as Channel 5-1 for legacy/marketing reasons but the actual frequency for antenna purposes is 20-1. You will note that 5-1 is listed as a virtual channel.

[Rob2687]

What echoing effect? Isn't digital supposed to solve these kinds of problems?

The reception is highly dependent on your location and the placement of the antenna but this "contraption" is a lot better than bunny ear antennas. The one I built wasn't the bowtie style one but a similar looking one called the Gray-Hoverman. This gives me all the stations from Toronto with just the antenna and 30ft rg5 cable without an amplifier.

[HawkMan]

Reflex/echo signals on digital CAN be used to enhance the signal, if the echo delay is very short. If it's long however it will pretty much kill the signal. Reflex signals can still be used to enhance the signal though, but then you need special or multiple antennas connected out of phase. The antenna/TV guy at work explained it to me, but it's been to long since I was doing antenna stuff for me to really get what he was saying :p