Found this site while researching antennas. Worked great for me. Check it out if you need a cheap UHF antenna.
http://uhfhdtvantenna.blogspot.com
http://uhfhdtvantenna.blogspot.com
How to build a UHF antenna...
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I just built the one from uhfhdtvantenna.blogspot.com, mounted it in my attic with a Magnavox rotator, and it works great! I went from an average of 50% signal strength to consistent 80 and 90% ranges.
How does your 8-bay build compare with a CM4228? I've been eying the feeder lines on mine between the 2 sides which I've heard causing return loss/radiation problems. As your build appears to have solved that problem, I am curious as to the result.
How does your 8-bay build compare with a CM4228? I've been eying the feeder lines on mine between the 2 sides which I've heard causing return loss/radiation problems. As your build appears to have solved that problem, I am curious as to the result.
I wondered the same thing but I think the only way to get an answer is to do it myself. Gotta admit if I had known about how I could have built my own 4228, I may have given it a shot before buying. Oh well, the 4228 looks better on my roof than 2 x 4's and chicken wire.
James
I wondered the same thing but I think the only way to get an answer is to do it myself. Gotta admit if I had known about how I could have built my own 4228, I may have given it a shot before buying. Oh well, the 4228 looks better on my roof than 2 x 4's and chicken wire.
James
These DIY antennas work better than what most people will give credit. I do believe their application is only for indoor use and fail to see how they will hold up to the weather/wind even if 1"x2" screen is used.
I had my CM4221-copy professionally tested (my neighbor is a retired brodcast engineer that now does OTA installs and has a patent-pending antenna design of his own). I'm getting similiar db readings (hand held meter) as a commercial-built CM4221 (4-bay). He was shocked to see this and was amazed I was locking digital stations up to 75 miles away out of my attic (using a balun w/CM7777 preamp).
He had some thoughts on possibly improving this DIY design for fringe areas:
1. get rid of the foil reflector. Run either no reflector or install 1x2 screen.
2. Use copper wire for the connecting wire and >
3. Use 300 ohm twin lead to 300 ohm input preamp to eliminate balun loss before preamp.
I'm on the edge of reception, so I need to be outdoors where the reception db measurements were favorable. This DIY project will not be installed outside. But I can see it working well for people that are closer to the towers than I.
These DIY antennas work better than what most people will give credit. I do believe their application is only for indoor use and fail to see how they will hold up to the weather/wind even if 1"x2" screen is used.
I had my CM4221-copy professionally tested (my neighbor is a retired brodcast engineer that now does OTA installs and has a patent-pending antenna design of his own). I'm getting similiar db readings (hand held meter) as a commercial-built CM4221 (4-bay). He was shocked to see this and was amazed I was locking digital stations up to 75 miles away out of my attic (using a balun w/CM7777 preamp).
He had some thoughts on possibly improving this DIY design for fringe areas:
1. get rid of the foil reflector. Run either no reflector or install 1x2 screen.
2. Use copper wire for the connecting wire and >
3. Use 300 ohm twin lead to 300 ohm input preamp to eliminate balun loss before preamp.
I'm on the edge of reception, so I need to be outdoors where the reception db measurements were favorable. This DIY project will not be installed outside. But I can see it working well for people that are closer to the towers than I.
Right, they aren't weatherproof at all. The other thing is that the CM4221 is pretty cheap so you're just not saving all that much if you don't have all the parts lying around. It's fun to play with, though. I decided to see just how crappy an antenna would work so I made four elements out of aluminum foil and cardboard, stapled them to a shoebox, ran aluminum foil between them, and taped a balun in the middle of the foil "phasing line". Worked quite well, getting in UHF stations from Allentown (about 30 miles away over hilly terrain) from my second story, at least as long as the balun stayed attached.
On the 4-bay, I have a balun at the feed point to a CM7777.
On the 8-bay, I have a piece of 300 ohm twinlead from each 4-bay section connecting at a central point on back of the antenna (which actually is my 300 ohm preamp input). I tried it w/2 baluns to a combiner to the CM7777, but it didn't perform as well as the twinlead setup.
For me the DIY 8-bay would not pull in the long distance stations as the 4-bay, so I've stopped messing with it. It could be the multipath or probably an error in assembly on my part.
On the 4-bay, I have a balun at the feed point to a CM7777.
On the 8-bay, I have a piece of 300 ohm twinlead from each 4-bay section connecting at a central point on back of the antenna (which actually is my 300 ohm preamp input). I tried it w/2 baluns to a combiner to the CM7777, but it didn't perform as well as the twinlead setup.
For me the DIY 8-bay would not pull in the long distance stations as the 4-bay, so I've stopped messing with it. It could be the multipath or probably an error in assembly on my part.
I also found that my 8bay did no better, and maybe worse, than a 4bay. Kind of a puzzle to me. On the weatherproofing subject, I think you can make it about as weatherproof as you want. One tip would be to have some kind of sturdy positioned horizontally a few inches above the highest element of the antenna for birds to perch on. I have noticed that alot of old commercial-grade antennas have broken elements, and I've seen alot of newer antennas with birds sitting on the elements.
I also found that my 8bay did no better, and maybe worse, than a 4bay. Kind of a puzzle to me. On the weatherproofing subject, I think you can make it about as weatherproof as you want. One tip would be to have some kind of sturdy positioned horizontally a few inches above the highest element of the antenna for birds to perch on. I have noticed that alot of old commercial-grade antennas have broken elements, and I've seen alot of newer antennas with birds sitting on the elements.
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Yeah, it's funny...I'm pretty close (within 30 miles) of most of the transmitters, but my little RCA antenna just wasn't cutting it. The antenna I built fit perfectly in my garage attic, and luckily, all of the transmitters are within 15 degrees of each other from here, so I rarely have to tweak the rotator. My 3-year old son and I built this antenna from uhfhdtvantenna.blogspot.com in less than an hour and I'm MORE than happy with it!! Since he watches PBS Kids here in St. Louis (and we don't get to watch hardly anything else) it's perfect...and FREE!
I assumed that MClever has only a 300ohm input on his amp, and thus saved unnecessary conversions from 300 to 75 to 300 to 75 again, but using two twinleads to connect to the amp rather than two baluns. I have the CM Spartan 3, which has a 300ohm input and a 75ohm output, I believe, so that is how I would combine two antennas, and it is one way I would join two halves of an 8bay. Does that make sense?
I assumed that MClever has only a 300ohm input on his amp, and thus saved unnecessary conversions from 300 to 75 to 300 to 75 again, but using two twinleads to connect to the amp rather than two baluns. I have the CM Spartan 3, which has a 300ohm input and a 75ohm output, I believe, so that is how I would combine two antennas, and it is one way I would join two halves of an 8bay. Does that make sense?
I built a 4228 and have purchased a new 4228. The factory one still works better than your home made one. Also the factory one will stand up to severe weather conditions. The home made one works great in the house for a set top antenna.Generally I don't have to turn it for the other stations, it receives then even from the back. I built one with solid copper wire and to my surprise the one I built with coathangers worked better. Don't waste your time building a Yagi antenna!! I built one , but it does not work at all! I have a 91XG factory antenna and it works better the the 4228, but a rotor is a must!
I built a 4228 and have purchased a new 4228. The factory one still works better than your home made one. Also the factory one will stand up to severe weather conditions. The home made one works great in the house for a set top antenna.Generally I don't have to turn it for the other stations, it receives then even from the back. I built one with solid copper wire and to my surprise the one I built with coathangers worked better. Don't waste your time building a Yagi antenna!! I built one , but it does not work at all! I have a 91XG factory antenna and it works better the the 4228, but a rotor is a must!
I use one of these to watch Huntsville AL HDTV (about 47 miles away). I have it in a window facing the towers, and I run the signal through a 24dB VHF/UHF amplifier to boost it up a bit.
My signal checker app (DVIco) reports 23-27 dB for every station except one. It wouldn't last a week outdoors, but it's just right sitting in my window.
A picture is in order (thanks to ImageShack for Free Image Hosting ).
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I would love to find a plan for a good single frequency VHF antenna. I have found lots of ham radio plans, but when I resize them for the MHz I need, they end up being a bit large.
My signal checker app (DVIco) reports 23-27 dB for every station except one. It wouldn't last a week outdoors, but it's just right sitting in my window.
A picture is in order (thanks to ImageShack for Free Image Hosting ).
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I would love to find a plan for a good single frequency VHF antenna. I have found lots of ham radio plans, but when I resize them for the MHz I need, they end up being a bit large.
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