[CM] fm again

Juan I Reyes juanig at ccrma.Stanford.EDU
Wed, 21 Nov 2007 11:02:23 -0500

Thanks a lot Peter,

This is more than what I wanted to know but now I get the picture. I am
not an RF person either and I always wondered why FM station transmitter
antennas were so huge while wireless gadgets are using real tiny
embedded antennas. 

Wow! I am really grateful scanned page and for pointing  another jewel
book on this subject matter.

With all this inspiration I might get into a sound installation
involving FM sounds and FM transmission :-0

  --* Juan

On Tue, 2007-11-20 at 20:49 -0500, plutek-infinity wrote:
> >From: Juan I Reyes <juanig@ccrma.Stanford.EDU>
> >Looking at these really nice pictures (priceless as Dave points out),
> >and out of curiosity, I can't resist to post this silly question:
> >
> >For an FM transmitter what it is the minimum length of the antenna for
> >broadcasting at a frequency around 100MHz. ?
> "Fundamentals of Radio" (Jordan, Nelson, Osterbrock, Pumphrey, Smeby, and Everitt - Prentice-Hall, New York: 1944) states that the velocity of electromagnetic waves is 300,000,000 m/s and that transmission of radio waves requires an antenna at least of the order of one-quarter wavelength, and most commonly one-half wavelength.
> given all that, i guess the wavelength would be 3m, the minimum antenna length would be 0.75m, and the most common antenna length would be 1.5m. of course, i may be wildly off on this, since i have no experience in the field -- just happen to own that very interesting book.
> see http://peterlutek.com/temp/antenna.jpg for a scan of the cogent bit of the book. (i'll be removing the scan in a day or two)
CCRMA, Center for Computer Research in Music and Acoustics
STanford University