This antenna is very makeshift however it works great. What I did was took a old air purifier and solved a TV signal problem. So I hacked a Oreck Air purifier to a excellent HDTV antenna. I made it out of parts I had laying around my house it has a total of 2 main things to make it work. I know it isn't as cheap as the aluminum foil and cardboard antennas however, those are often shady when it comes to working correctly. I recently challenged my dad saying I could build a HDTV antenna for under $5 bucks in less than 20 minutes that works better than his $50 antenna. The antenna he is using is the Winegard FlatWave Amped Indoor HDTV Antenna. It works ok but not great. He picks up about 23 HD Channels and 2 non-HD without the foreign language, and shopping channels, with my antenna, I am picking up 31 HD Channels and 5 non-HD channels without the foreign language, and shopping channels. To test this we placed the antennas in the same spot for each of them and counted the channels. Let me add that my dads antenna is made with silver and my antenna is made of stainless steel. With a super short amount of research (which I doubt is true) but, I found that Stainless steel is able to pick up 8X more TV Waves than Silver according to yahoo answers but what ever! It works! Also to make my dad's antenna complicated it needs a signal amplifier to work properly. My design doesn't need a amplifier. I am wondering what would happen if I put a TV signal amplifier on mine! So let me now tell you how to make this cool antenna.  

The list of supplies: 
1) You will need an Oreck Air Purifier Cell assembly
(Second Photo)
2) 75 ohm coaxial converter. (Third photo)
3) 1 coaxial female to female cable. (Fourth Photo)
4) Electrical tape
5) Wire strippers 

What you want to do first is take the Oreck cell assembly and use either end of the assembly. Then take the 75 ohm coaxial converter. Then if the wires are not already stripped, then strip them. Then attach the wires into the 2 metal pieces. (see pictures)
Then take several pieces of electrical tape and just cover the wires where they connect to the metal piece and put electrical tape just to hold down the wires.

Connect the coaxial cable to the antenna. Connect the other end to your TV. Adjust the position to which ever way works better for you. Please leave any recommendations in the comments below. Only nice recommendations and comments please!