Which city are you in? I'm in downtown Ottawa and with a store-bought HDTV antenna I get only 2 stations. Maybe I'll have to go buy a spool of wire!
How I made an HDTV antenna so I could watch Jeopardy last night
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Re: How I made an HDTV antenna so I could watch Jeopardy last night
#42Which city are you in? I'm in downtown Ottawa and with a store-bought HDTV antenna I get only 2 stations. Maybe I'll have to go buy a spool of wire!
South end of Ottawa :)
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#43Thanks, I'm glad you took our comments to heart :) Two questions: 1. What exactly is the purpose of the cardboard tube? I'm guessing the key point is that it's non-conductive, but would the same coil work without the cardboard? (not very knowledgable about antennae I admit) 2. How the hell does that connector even work? It looks so marvelously out of place ... does this mean the wire mesh around the normal coaxial ca…
The shell of coax (and what's in the space between it and the center conductor) also affects the impedance of the cable or antenna system. It's generally not that critical for a receiving antenna.
Sticking up almost any wire more than a few wavelengths long will collect a reasonable amount of a strong signal. A truly resonant antenna for the frequency you're interested is a lot better, but not that helpful for general HDTV viewing where the frequencies range all over VHF and UHF.
One of the amazing things I've learned from years of ham radio is how many unseen and unpredictable things affect radio signals. You can move your antenna twelve inches to the left and lose a signal completely, especially inside a structure. Or an airplane flying overhead can reflect enough "multipath" signal to wreck your TV viewing for 30 seconds. Of course your own body blocks a lot of signal and is capacitively coupled to the antenna system as you adjust it. So if you're playing with an HDTV antenna and are too young to remember the fun of constantly adjusting TV rabbit ears, just keep tweaking until you get a good signal.
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#44Re: How I made an HDTV antenna so I could watch Jeopardy last night
#45You'll get even better reception if you shape the wire in a fractal pattern, like this: http://www.instructables.com/image/FDXQQVBFP8NM7YF/Create-fr...
Nathan Cohen made this discovery after listening to a Mandelbrot talk on fractals: http://en.wikipedia.org/wiki/Fractal_antenna#Fractal_element...
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#46This article is excellent! And thank you, chaosmachine, for providing instructions for replication. It's my strong opinion that everything here is ethically sound. This sort of "hacker" culture is the meat and potatoes of what drives innovation in the United States today, and whether this specific incident results in a new product or simply higher security by cable providers, progress has been made.
What do cable providers have anything to do with this?
He built his own antenna to receive local channels that are broadcast over the air. These are broadcast specifically so that people with antennas can receive them.
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#47Thanks, I'm glad you took our comments to heart :) Two questions: 1. What exactly is the purpose of the cardboard tube? I'm guessing the key point is that it's non-conductive, but would the same coil work without the cardboard? (not very knowledgable about antennae I admit) 2. How the hell does that connector even work? It looks so marvelously out of place ... does this mean the wire mesh around the normal coaxial ca…
The shell of coax (and what's in the space between it and the center conductor) also affects the impedance of the cable or antenna system. It's generally not that critical for a receiving antenna. Sticking up almost any wire more than a few wavelengths long will collect a reasonable amount of a strong signal. A truly resonant antenna for the frequency you're interested is a lot better, but not that helpful for genera…
"...too young to remember the fun of constantly adjusting TV rabbit ears..."
Too young, ha! I use rabbit ears on my HDTV (no cable, just netflix + locals is enough for me) and laugh when I go to Best Buy and see "state of the art high definition" antennas for anywhere from $20 to $100. The same laugh hits me when I go down the gold plated monster cable isle, but that's a different story.
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#48You'll get even better reception if you shape the wire in a fractal pattern, like this: http://www.instructables.com/image/FDXQQVBFP8NM7YF/Create-fr... Nathan Cohen made this discovery after listening to a Mandelbrot talk on fractals: http://en.wikipedia.org/wiki/Fractal_antenna#Fractal_element...
"Nathan Cohen made this discovery..."
He's the reason you don't have a stubby antenna sticking out of your cell phone anymore. Really cool story.
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#49Which city are you in? I'm in downtown Ottawa and with a store-bought HDTV antenna I get only 2 stations. Maybe I'll have to go buy a spool of wire!
Go to tvfool.com and put in your addresses. From what I can find they have Canada data in their DB too. The first step to understand how to get good reception is to learn where all the towers are located and what band they broadcast on.
Re: How I made an HDTV antenna so I could watch Jeopardy last night
#50You can use http://www.tvfool.com/ to chart the strength of nearby TV signals based on your location. It includes both US and Canadian broadcast towers.
I'd be interested to know the strength of the signals you're able to receive with your paper-towel-tube antenna design.