Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!uunet!news.larc.nasa.gov!grissom.larc.nasa.gov!kludge
From: kludge@grissom.larc.nasa.gov ( Scott Dorsey)
Newsgroups: sci.electronics
Subject: Re: Commercial radio transmitters
Message-ID: <1991Jan2.171317.18275@news.larc.nasa.gov>
Date: 2 Jan 91 17:13:17 GMT
References: <1990Dec20.172920.7325@phri.nyu.edu> <1990Dec21.135235.22887@cfctech.cfc.com> <1990Dec28.203208.2631@news.larc.nasa.gov> <37390@cup.portal.com>
Sender: news@news.larc.nasa.gov (USENET Network News)
Reply-To: kludge@grissom.gatech.edu ( Scott Dorsey)
Distribution: na
Organization: NASA Langley Research Center
Lines: 23

In article <37390@cup.portal.com> dbell@cup.portal.com (David J Bell) writes:
>from Scott Dorsey/ Kaptain Kludge:
>
>>If there are two towers for an AM station, I would expect it is because
>>they are using a long antenna sling between the two towers.  AM has a
>          ^.... Hmm? Usually this was/is to allow ....^
>           directional control of the transmitted signal,
>           by feeding the two or more towers in particular
>           phase relationships.

Absolutely true.  I didn't think about that here, far away from the major
markets.  But there are still a whole lot of horizontal AM antennae in
use... our local daytimer uses a dipole hung between two towers and does
get his signal out.  Again, with AM, polarization doesn't mean very much
because of the long wavelength (as opposed to FM where you'll lose 10 dB
with crossed transmit and receive antennae (and yes there are still some
FM stations that haven't gone to circular polarization yet)).

--
Scott Dorsey/ Kaptain Kludge
NASA Langley Research Center, Aircraft Guidance and Control Branch

Disclaimer: Neither NASA nor Lockheed really know anything about what