Path: utzoo!attcan!uunet!tektronix!tekcrl!tekgvs!jans
From: jans@tekgvs.GVS.TEK.COM (Jan Steinman)
Newsgroups: sci.electronics
Subject: Re: Shortwaves
Message-ID: <4011@tekgvs.GVS.TEK.COM>
Date: 29 Sep 88 18:05:15 GMT
Organization: Tektronix Inc., Beaverton, Or.
Lines: 25

<<I would like to get a short-wave radio... (for) high-quality receptions of 
broadcasts from Europe and Central and South America.>>

<...there is no such thing as "high-quality" shortwave reception, certainly 
nothing worth using a stereo system for. Stations fade in and out due to the 
vagaries of long-distance transmission, bounce off the ionosphere, and all 
that.>

Well, at least not for the money you quoted.  It is certainly possible to get 
considerably better quality reception than can be had with a basic receiver.  
Many foreign news clips come to your local station via shortwave during part of 
their trip, especially those of BBC, which (as of 1982, at least) had an 
extensive shortwave relay system.  (They may have gone satellite by now.)

The basic technique for improving reception that has a signal strength 
discontinuous in space uses what is called a "diversity combiner".  Two or more 
receiver front-ends tuned to the same frequency are fed by antennas that are 
separated by a large fraction of a wavelength.  The resulting signal strengths 
are compared, and the receiver with the strongest signal is fed to the audio.  
Several "golden ears" auto stereos do the same thing to eliminate or reduce 
multipath distortion on FM.

:::::: Software Productivity Technologies -- Experiment Manager Project ::::::
:::::: Jan Steinman N7JDB	Box 500, MS 50-383	(w)503/627-5881 ::::::
:::::: jans@tekcrl.TEK.COM	Beaverton, OR 97077	(h)503/657-7703 ::::::