Was fiddling around my attic in the house I've lived in about a year, and discovered the previous owner had at one time constructed a TV antennae using wire connected to terminals. It's a four sided antennae, each side running about 10 feet. I'm wondering if this could be used to pick up OTA HD signals. I'm pretty close to the antennae cluster in L.A. County (91001 zip). Using a silver sensor in the attic, I get CBS and ABC pretty reliably, and everything else sketchy, with Fox not at all. Does this seem worth the effort (would just have to buy a new attachment for the coax cable)? Thanks in advance.
Homemade OTA antennae?
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You can try, though it doesn't sound like a configuration I've heard of before; it might have been used for some purpose other than VHF/UHF television.
It'll either work or not. No harm should come for trying. Odds are if a silver sensor isn't working well for you and if you're close to the transmitters, you probably need something rather directional that can reject reflected signals well, so I wouldn't hold my breath that what's up there is going to be an improvement. You'd probably be better off trying some commercial antennas that are very directional.
It'll either work or not. No harm should come for trying. Odds are if a silver sensor isn't working well for you and if you're close to the transmitters, you probably need something rather directional that can reject reflected signals well, so I wouldn't hold my breath that what's up there is going to be an improvement. You'd probably be better off trying some commercial antennas that are very directional.
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Don't forget to don your tinfoil hat before firing it up! 
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I'm not sure how accurate that 99% number is.
We live in NJ and just had our roof reshingled (whether that is meaningful or not isn't something I can attest to, but it is information). My guy put my antenna (a Winegard 9095 and a pre-amp) suspended by wire in my attic. I receive all the Philly stations (pointed the other direction would get me the NY stations) perfectly. Saves the WAF of a 10' mast above the house with a big Christmas Tree as well as the weathering effect of having it outside.
I'm using a Leviton 47692-GSM (1x8 2GHz Distribution Module) to feed the splits to various locations around the house. The Leviton's power is tuned all the way down or I'd overload the HR10-250 with the signal.
Given that I can avoid combining signals and then resplitting them, I like using separate feeds for each line (although the outlet behind the TV now has far too many lines coming out - 2 x sat, 1 cable, 1 OTA, 1 phone, 1 net, and lines going IN to the sub and sat speakers. Good Grief. lol.
Andy
We live in NJ and just had our roof reshingled (whether that is meaningful or not isn't something I can attest to, but it is information). My guy put my antenna (a Winegard 9095 and a pre-amp) suspended by wire in my attic. I receive all the Philly stations (pointed the other direction would get me the NY stations) perfectly. Saves the WAF of a 10' mast above the house with a big Christmas Tree as well as the weathering effect of having it outside.
I'm using a Leviton 47692-GSM (1x8 2GHz Distribution Module) to feed the splits to various locations around the house. The Leviton's power is tuned all the way down or I'd overload the HR10-250 with the signal.
Given that I can avoid combining signals and then resplitting them, I like using separate feeds for each line (although the outlet behind the TV now has far too many lines coming out - 2 x sat, 1 cable, 1 OTA, 1 phone, 1 net, and lines going IN to the sub and sat speakers. Good Grief. lol.
Andy
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The 99% number is based on actual measurements a television engineer has made from numerous actual attics of differing construction and outside those same homes with the same antennas.Andy in NYC said:
Signal level doesn't matter that much as long as the signal level is a minimum threshold above the noise level.
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Sorry but I have to correct another 90% statement (other thread also)dswallow said:Except his silver sensor isn't doing well in the attic.
Also note that 99% of the signal is blocked by the average attic. I'd be curious to know how well the silver sensor does outside the attic.
Ok maybe you saved yourself by saying 'average' but i'd expect a more accurate and detailed statement from someone with more knowledge No way is 99% of the signal blocked unless you have some seriously reflective stuff on the roof. If that is 'average' in America, well I truly dont know that. People that have homes with just wood/shingles, can get a significant signal through just fine.40 miles from the towers, from my attic mount, I was getting 2 low UHFs on the HDtivo with 90s signals and even upper UHF (ch 64/67) at a signal of 70ish to 85 ish. It was 2 lower powered mid ranges that were tough for me.
For comparison, even outside, the high UHF did not improve beyond the 85 i had as my indoor maximum. But what it did do, is help stablize the signal so yes, i was losing something, but nothing near 99% of the signal.
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I'm talking 99% of the signal energy. That has nothing to do at all with the "signal level" readings you see on your receiver; that represents an error correction usage rate showing whether or not the signal is being decoded well.newsposter said:Sorry but I have to correct another 90% statement (other thread also)
40 miles from the towers, from my attic mount, I was getting 2 low UHFs on the HDtivo with 90s signals and even upper UHF (ch 64/67) at a signal of 70ish to 85 ish. It was 2 lower powered mid ranges that were tough for me.
For comparison, even outside, the high UHF did not improve beyond the 85 i had as my indoor maximum. But what it did do, is help stablize the signal so yes, i was losing something, but nothing near 99% of the signal.
Here's a post from the guy who actually has made the measurements; Somewhere he's probably talked about it more specifically but last year he sent me some of his raw data graphed -- 20db loss is typical; that means 1% of the signal is making it to an antenna in your attic versus what would get there if the antenna were outside and unobstructed.
http://www.avsforum.com/avs-vb/showthread.php?p=6307937&&#post6307937
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I had no idea. Wonder where i can get more detail on what this meter is telling me. they really shouldn't label it as a signal meter if that's what it's not!dswallow said:
So i was only getting 1 percent energy in and got that good a pic. Wild..wonder why they dont just cut the signal down since for outside antennas you dont need that much
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It's all your fault if martians invade earth the day after you hook up that contraption.
The antenna design sounds like what's called a rhomboid. With the dimensions you gave, it's not appropriate for the UHF signal range used for digital TV... it's a low-frequency antenna for AM radio. While you might pick up something, it sure won't be anywhere near optimal. If you're in a fringe area, you really should go for a high-gain antenna designed for UHF.
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I gotta tell you guys, you really brought back the memories.
When I was a kid, I'd spend my summers with my uncle who ran a dairy farm with grapes, almonds, chickens and pigs. A new radio station came into town, Chico, and the milk production dropped. My uncle called them to turn off their radio station because the electric waves were messing up his milk production.
Well, they didn't respond so he took some bailing wire and we spread it on the ground and measured meticulously. Once we got the right length, he wrapped the wire around the pig sty and connected a 100 watt bulb to the two ends of the wire. The bulb lit and kept the sty lit 24/7 for the remainder of the summer.
When I returned the following summer there was no light (the wire remained). I asked about the light and got told that the "damn government made me take it down".
So, ******, be ready for the "damn government" to pay a visit when you hook that thing up.
....and, good luck!
When I was a kid, I'd spend my summers with my uncle who ran a dairy farm with grapes, almonds, chickens and pigs. A new radio station came into town, Chico, and the milk production dropped. My uncle called them to turn off their radio station because the electric waves were messing up his milk production.
Well, they didn't respond so he took some bailing wire and we spread it on the ground and measured meticulously. Once we got the right length, he wrapped the wire around the pig sty and connected a 100 watt bulb to the two ends of the wire. The bulb lit and kept the sty lit 24/7 for the remainder of the summer.
When I returned the following summer there was no light (the wire remained). I asked about the light and got told that the "damn government made me take it down".
So, ******, be ready for the "damn government" to pay a visit when you hook that thing up.
....and, good luck!
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That's what I thought, too. Rhomboids were also used for DX-ing distant TV stations, but if I remember correctly they were pretty frequency-specific, and not very directional, even though they had a lot of gain. Probably not a good choice for ATSC, especially when a 4228 can be had for $39.wje said:
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I don't know where this 99% figure comes from but it's way off. I have a field strength meter and measured signal level from a 4221 on the roof and then in the attic. Raw signal strength delined by a little less than half. I still have more than enough to split it and feed 3 receivers, including an HD Tivo. I am 16 miles from the transmitters and live in a one story rambler.dswallow said:Except his silver sensor isn't doing well in the attic.
Also note that 99% of the signal is blocked by the average attic. I'd be curious to know how well the silver sensor does outside the attic.
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By "half", I'm assuming you mean about 3 dB? If so, you are correct. The signal would have to drop by 20 dB to be 1/100th of the original strength. Not too many received TV signals, ATSC or NTSC, could tolerate 20 dB of loss, so the preponderance of successful attic installs over the last 5 decades makes me think the "study" is flawed.
A 20 dB loss sounds about right for an attic that has metalized film insulation bats or metal screen under stucco, or the equivalent, and a 3 dB loss sounds about right for an attic without either of those little problems, so maybe a better "study" would include delving into the construction materials rather than just trying a bunch of different attics blindly in serial fashion. Odds are against it, but maybe the "study" was done in a neighborhood using the same construction techniques in all attics tested. Bottom line, it doesn't appear to be very empirically sound.
A 20 dB loss sounds about right for an attic that has metalized film insulation bats or metal screen under stucco, or the equivalent, and a 3 dB loss sounds about right for an attic without either of those little problems, so maybe a better "study" would include delving into the construction materials rather than just trying a bunch of different attics blindly in serial fashion. Odds are against it, but maybe the "study" was done in a neighborhood using the same construction techniques in all attics tested. Bottom line, it doesn't appear to be very empirically sound.
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You are of course, right when you say the attic construction material makes a HUGE difference. Mine home is made of wood with asphalt shinges. No metal is used which could cause reception issues. I like the reliability of over the air reception. No matter how hard it storms, I can always pickup our local digital stations and see what is going on.
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Oh my God.
I just reread the "source" of the study. Not only did the guy only do 3 attics, he mentioned 15-20 dB, not "99%". While 20 dB of loss would be equivalent to 1/100th, 15 dB would be more like a loss of about 65% of the signal, so the truth probably lies somewhere in between for his little non-scientific sample. Not only that, but by the name and location, I think I know this guy, and if I do he's one of the more "clueless" fellow broadcast engineers I've had the "pleasure" to know or work with (1983-90) in the last 30 years. And I'm honestly trying to be nice, not cruel, when I say this.
Much of what he says is true, however. But that sweeping generality about vertical directivity? Huh-uh. Typical arrogance of that guy. The 4228's polar plots look very similar in both H and V axes, as do those of many other antennae. And tilting a directional antenna and noting the drop-off is hardly any indication of its vertical directivity when you aren't in free space but are traversing normal (or abnormal) terrain. Also highly unscientific, and also typical of this guy's fuzzy thinking processes.
I just reread the "source" of the study. Not only did the guy only do 3 attics, he mentioned 15-20 dB, not "99%". While 20 dB of loss would be equivalent to 1/100th, 15 dB would be more like a loss of about 65% of the signal, so the truth probably lies somewhere in between for his little non-scientific sample. Not only that, but by the name and location, I think I know this guy, and if I do he's one of the more "clueless" fellow broadcast engineers I've had the "pleasure" to know or work with (1983-90) in the last 30 years. And I'm honestly trying to be nice, not cruel, when I say this.
Much of what he says is true, however. But that sweeping generality about vertical directivity? Huh-uh. Typical arrogance of that guy. The 4228's polar plots look very similar in both H and V axes, as do those of many other antennae. And tilting a directional antenna and noting the drop-off is hardly any indication of its vertical directivity when you aren't in free space but are traversing normal (or abnormal) terrain. Also highly unscientific, and also typical of this guy's fuzzy thinking processes.
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nice to see i'm not the only one that thought the 99% was a tad off
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