Warren Oates hath wroth:

In article ,
Jeff Liebermann wrote:

I'll pretend not to mention commercial antennas that are sold without
any useful specifications, patterns, or simulations. That's one
reason I've often considered going into the antenna business. The
more they resemble a gold plated metallic scrap heap, the better they
sell. Few customers can see how they operate. Product comparisons
are difficult or impossible. Magic is everywhere. Yeah, the antenna
biz looks good.

I remember seeing one of those "rabbit ears" tv antennas, unpowered,
shaped like a little satellite dish that you could rotate, selling for
like 14.99 or something and on the box it said "Uses RF Technology!!"

I think that was the rabbit ears with the gold plated 6" dia dish
antenna in the middle.
http://www.radioshack.com/product/index.jsp?productId=2455309
Yep... same junk but without the gold plating.

It was true, though, I guess.

You missed all the fun in the late 50's. That's what got me
interested in radio/RF/wireless/whatever. There was this character
named Charles Torrelli, that advertised in Popular Electronics selling
a "Turn your house wiring into a giant 1,000 ft TV antenna". It
consisted of a Bakelite box with a "capacitator" inside. One end went
to the AC power line, the other end to the twin lead input on the TV.
Since there was no transformer in the box, and a good chance the at
the TV was of the AC-DC variety, there was about a 10% chance that you
could get fried connecting the device.

Needless to say, house wiring does not make a great VHF antenna, but
that didn't stop Torrelli. It also inspired me to learn a bit more
about the technology as all the experts were telling me that it can't
work, but none supplied any reasons that made sense.

Further investigation on my part resulted in the a minor
electrocution, which provided additional inspiration and motivation. I
instantly concluded that anything that powerful must also be
interesting and possibly useful, so I elected to study electricity.
Additional inspiration was later provided by the launching of Sputnik,
which converted anyone that could spell "engineering" into some kind
of freedom fighter.

I once modeled a Radio Shock TV yagi antenna. On some channels, it
had more gain in the backwards direction than forward. A simple bow
tie and reflector antenna would have worked much better, except that
RS doesn't sell them any more. Also, TV antennas are not rated in dBi
gain. They use "miles" instead.




--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558