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Antenna Question

Started by Mags, Tuesday Jan 24, 2006, 10:12:37 AM

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Mags

Hi Folks:

Recently installed a Radio Shack antenna in my attic.  I have a question as to which direction to point it.  I know the compass direction, but when I read the antenna directions I was, to say the least, surprised.

The directions told me to point the smaller end towards the attenna source - and not the "big" end, where the elements are much larger.  It seemed to make sense to me, as the elements would then act like a catchers mitt.....

But I always thought the large end would point towards the towers (similiar to the front of a stealth fighter plane going forward.

Were the directions correct?  If so, I learned something!

Gregg Lengling

The directions are correct, and yes you learned something.  On a Yagi antenna there are 3 types of elements:  Driven Elements (these are mid sized ones with the direct connection to the antenna cable), Reflector Elements (these are the big ones at the rear of the antenna that help catch and reflect signals back to the driven elements) and then the Director Elements (these help direct the captured signals towards the reflectors and driven elements).  The nomenclature comes from engineering as a transmitting antenna, that's why the active elements are called driven elements, in a transmitting station these would receive the power from the transmitter.

You'll notice these are designed to operate in the horizontal plane, there are also variations that mount in the vertical plane but are used for Fixed station to Mobile station signals, as mobiles usually operate  with a vertically polarized antenna.  In areas of extreme signals, overload and multipath can be a problem, and sometimes shifting the polarization by 45 degrees can cure the problem.

Good luck, and just remember you keep learning until the day you die.
Gregg R. Lengling, W9DHI
Living the life with a 65" Aquos
glengling at milwaukeehdtv dot org  {fart}

Mags

Thanks for the quick response.  I have another question for you if you don't mind.

There are a number of digital channels that antenna web says I should be getting but am not.

I do not have an antenna amp, but fairly close to the antenna I  have a RF distribution point that has a amp built in.  Would I benefit from also adding an antenna amp into the equation, placed before the RF distributer?

Thanks!