Question about basic TV antenna

[jimdagys]

I have a basic TV antenna (see picture). I pulled it off an old TV and added about 4 feet of 300ohm cable and a 300 to 75 ohm balun. The antenna works fine for my needs. However, if you search out homemade antennas, you find elaborate multi element with reflector antennas, no simple ones. Why aren't the simple loop designs listed?

[usually_quiet]

Loop antennas work best for UHF frequencies and relatively strong signals. The larger multi-element "whisker" antennas with reflectors work better for situations where signals are weaker, and they sometimes incorporate a pair of longer "whisker" elements specifically for receiving VHF frequencies, which are still used in some areas of the US.

[betwixt]

The other drawback to simple antennas like the one you show is they are not very directional. In fact a loop will receive equally well when rotated 180 degrees. The "Yagi" antenna, consisting of a boom crossed with elements has the property of not only being more sensitive to weak signal but also being directional. In your case this may not be important but in fringe signal areas where one weak transmitter may have to be picked out among others, the ability to 'aim' can be very important. Being directional also has another advantage, it helps to eliminate the same signal arriving from different directions when it bounces off buildings and other solid objects. A signal travelling along a different path because it is being reflected will have a small time delay compared to the original, in "the old analog days" this was seen as a ghost image but in the digital era it can result in complete scrambling of the data and loss of picture.

Brian

[usually_quiet]

I'm guessing the reason why there are not many online instructions for building a loop antenna is that it is often possible to pick one up in a store for a couple of dollars to ten dollars, depending on the model.

Manufactured 2-Bay UHF antennas are more expensive. http://www.newegg.com/Product/Product.aspx?Item=N82E16882467001&name=Satellite-TV-Accessories