Building My Own HDTV Antenna

February 4, 2008

Synopsis: The self-made antenna worked–for my friend. HDTV antennas are just conventional UHF/VHF antennas. iTunes may turn out to be the cheapest solution for our viewing patterns.

The Self-Made Antenna Experiment

Like any scientist, I consider all experiments carried all the way through a success, even if one negates my initial assumptions and expectations. It is even better if new insights can be gained. In that context, I had success with my DYI HDTV Antenna.

The coaxial cabling in my house is so bad that I cannot receive standard TV channels properly on my HDTV. The latest season of Lost has just started & the wife wants me to make TV happen. My options were

  1. calling the cable company to fix it (accompanied with the hollow threat that I would switch to FIOS if they didn’t, which I had attempted several times but given up on after Verizon’s online application was not able to recognize my address and their sales interactive voice response system gave me a 15-minute run-around asking for my [non-existing] Verizon phone number) or
  2. buying a commercial HDTV in-house antenna.

I picked option 3, which was to build my own antenna according to the instructions in this video on MetaCafe:
Coat Hanger HDTV Antenna

Since I was fresh out of coat hangers, baluns and various other hardware, I spent about $15 on materials from various places, which I considered a decent price to pay for some fun. A friend of mine and I then commenced to leisurely put the antenna together whilst taking care of the kids (the latter causing this to be an hour-long project).

I had purposefully kept my expectations low about whether this contraption would work, so I was positively surprised when the HDTV tuner picked up 20 HDTV channels on our second attempt (after having “straightened out” a few parts of the antenna that apparently were causing some problems). The 11 religious & church channels among those channels found came in crystal-clear without skipped frames, pixelization or missing sound. We were not so lucky with the major networks’ channels, though and even after several more minutes of tweaking the antenna and moving it about the living room, we had to concede defeat (on that end). All the important channels had such poor reception that we often saw nothing but a “receiving data” message that would not go away or the dreaded “no signal” message. If we got a picture, it was a still frame that refreshed every minute with many artifacts. There was no sound.

How could it be that half of the channels found had no issues while the other half was pretty much unusable? I asked my friend to take the antenna with him to his Portland East-Side home and try it there, just to get another data point (of view, literally) for the experiment.

He called the next morning with the good news that for all but two channels, our self-made HDTV antenna was performing better than the commercial, amplified HDTV antenna he had bought a while ago. He gave me his old, commercial antenna to see whether I would have more luck with it (which I didn’t).

Where’s The Tower?

It dawned on me that the awkward location of my house on the south side of a hill in South-West Portland may have something to do with the poor reception. After few minutes of research I found the location of TV transmitters for several major Portland-area networks, which is at the Sylvan Ridge in the West Hills at the corner of SW Barnes Road and SW Skyline Blvd (Map View). The FCC provided a helpful resource to find TV stations, channels and transmitters. Consumer Electronics Association’s AntennaWeb is also helpful for selecting antennas. You can plug the longitude and latitude for locations found into Google Maps using the following format: 45° 31′ 14″ N, 122° 44′ 37″ W (the first one is the latitude, the second the longitude).

Using Google Earth I discovered that even though the towers are only 4.5 miles directly north of my residence, there’s a hill blocking the line-of-sight. I would have to erect a 70 feet tall tower to get line-of-sight.

Electro-magnetic ground-effects can be funny. I once tried to get a high-speed wireless Internet connection over a distance of only 3 miles, but there was a little bump in between the radio tower and my office location. The technician doing the site survey said that even though the station was in line-of-sight, the bump messed with the signal sufficiently enough for it not work. More details about this can be found here: Fading & Multi-path Interference

So, What Now?

In order to overcome the signal limitations I have to deal with, I would have to spend some serious money on a mast and at least two highly directional, high-gain antennas. That’s not really an option, for aesthetic reasons alone.

I will probably call the cable company and have them fix everything. My drop is almost 100 feet long and its using regular R6 when it should be R11. I am just concerned about losing my Internet connection and not getting it back.

In order to get cable HDTV, I would need to pay $6.50/month extra with Comcast and still have to watch commercials during shows.

Maybe the convenience is worth the small premium over all this hassle and iTunes ends up being the best deal? But it’s not HDTV, so I am not sure …

Sweet Memories

This whole experience reminded me of a time during my childhood, growing up in socialist East Germany. The West Germans (and presumably Americans) had put powerful terrestrial TV and radio antennas along the border between East & West Germany, blasting the signal as far into “enemy territory” as they could. East German engineers (privately) devised antennas and amplifiers to pick up those signals.

Together with our duplex neighbors, we put a 10 feet tall mast on top of our 20 feet tall house and attached several 6 to 10 feet long high-gain antennas with amplifiers to it. We then would align the antennas in the direction of the approximate location of the “capitalist” radio & TV towers, turn on the TV, tune for the channel (by hand!) and then slowly move the antenna in 1/4 inch steps (or smaller) until the signal was clear. We would repeat that for each of the 3 (or 4?) antennas. After every major storm.

The towers from which we received the signals were over 80 miles (127 km) away.


4 Responses to “Building My Own HDTV Antenna”

  1. Combobulate Says:

    I made one here with pictures thanks for the info on the lat long directions.

  2. Tony C Says:

    Hi I had to tell ya I did biuld your antana and today I went to Radio shack and bout there most expence hdtv anatana that came with a 20db gain you plug into the wall I tryed both antanas on the same tv even with the db gain there antana did not do any better so I took it back, I would like to know how to make that little peace the db gain that you plug into the wall thanks Tony

    • TJ Says:

      Tony, in simplified terms, the gain of an antenna is how “well” it receives the signal. I do not know what the gain for the antenna is I built here, because I don’t have the equipment to measure/calculate it. What you are referring to that can be “plugged into the wall” is an amplifier (sometimes called a preamp based on its location). The problems with amplifiers is that they amplify everything, including noise and interferences (unless it’s something more sophisticated that recognizes those things and can filter them out, but I know close to nothing about such devices).
      If your TV signal quality is poor, please try to make sure that you are not dealing with one of the various interference issues mentioned in my post. If you are simply too far away, you can buy a “stand-alone” amplifier that may help. Often just installing the antenna higher can make a huge difference.

  3. Mike T Says:

    I stumbled on to your site, and found this article on building an HDTV antenna. In my case, I wanted to watch TV stations 70 miles away. So I took this basic design and mad it bigger – as in stacked more elements.

    Like you, I put mine on top of my 30 ft. tower. I get about 35 HDTV channels almost all of them at least 70 miles away.

    One thing to consider when building an HDTV antenna out of coat hangers, they are made of steel, which rusts. So in time in the weather, the HDTV antenna performance will degrade.

    To remedy this, I used copper wire, and soldered all connections.

    If you are interested in my HDTV antenna plans, just go to my website.

    — Mike

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