Thursday, June 26, 2008

Aerial Views

On an episode of "The Red Green Show" in an effort to improve his radio reception, Red duct tapes a TV antenna complete with rotor onto the roof of a Ford. As with a lot of Red Green's duct tape engineering, you might be thinking, "It's ridiculous looking, but I'll bet it could really work."

Well, yes. It would work - to a point. A TV antenna is typically capable to receiving FM signals and, properly installed, will boost the signal far beyond the average "whip" or wire in the back window. The problems with Red Green's configuration are:

A: The antenna is not mounted high enough to eliminate multipath interference from reflective surfaces.

B: The directional properties of the Yagi antenna design requires the operator to turn the antenna in the direction of the transmitting station as the vehicle turns in various directions.

C: There is more than likely signal loss inherent to the mismatching of impedance between the 300 Ohm Yagi connector points and the input port of the car stereo, probably loaded for an impedance of approximately 50 Ohms.

Anything else? Oh, yeah...


So, nobody in his right mind would mount a TV antenna on his car. Right?

Nope. That's not a Soviet spy car. And it's not a Photoshop trick. That's a real BBC television detector unit, mounted on what appears to be a sixties era Vauxhall estate. I'll bet that thing was fun to drive. Kinda like holding a beach umbrella while driving a golf cart.

Fred's TV engineering blog has lately focused on the reemergence of the venerable fixture of modern life, the television antenna. Digital TV has brought about the need for an outdoor antenna for some viewers, and that means a re-educating, or maybe a first-time educating, on the basics of how an antenna works.

You used to see some pretty exotic looking hardware up on rooftops and towers back before home satellite service, especially in rural areas. There are various kinds of charts, technical papers, and engineering studies that explain how these devices work. I am here to put it all into "laymen's terms." It's really very simple: the more channels you want to watch, the more money you have to spend.

And while some of us have cozy memories of watching charming family programing of yesteryear - Lassie, Howdy Doody, atomic bomb tests - with nothing more than rabbit ears, the demands of digital high definition television require a more sophisticated antenna in order to bring true, rich color and tonal reproduction to the dead bodies on CSI.

And where are we going to find this kind of antenna technology? Not from the rooftops of American rural homes. I say we look to where superior antenna technology has always existed - on the rooftops of vintage overweight, underpowered, British automobiles. Behold, The BBC Television Detector vehicle!

I mean if these things could sniff out an unlicensed TV set from several yards away, surely one can pull in "Deal or No Deal" without a problem. Right?

Now, if I could just figure out a way to duct tape one of these things to my roof...