[AMRadio] AM Transmitter "quality"

Bernie Doran qedconsultants at embarqmail.com
Tue Sep 15 18:21:13 EDT 2009

Grant has this correct!! for those that doubt, ask youself this. How often 
do I use phonetics when speaking face to face? And why not?   Ans. BECAUSE 
YOU ARE HEARING THE FULL SPECTRUM!  Bernie W8RPW----- Original Message ----- 
From: "Grant Youngman" <nq5t at tx.rr.com>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Tuesday, September 15, 2009 2:31 PM
Subject: Re: [AMRadio] AM Transmitter "quality"

> On Sep 15, 2009, at 1:11 PM, Joe Hankins wrote:
>> I
>> operation was effective radiotelephone service. Human speech falls
>> into
>> the range between 300 and 3000 Hz. There are sounds outside this
>> range,
>> but they do not contribute to intelligibility.
> That's actually a complete myth.  There are frequency components both
> above and below this range which, if present, contribute in a major
> way to speech intelligibility.  The fundamental frequency in  vowels
> is closer to 100 Hz, and frequencies well above 3 Khz (actually above
> 4Khz) are needed to reliably distinguish an "f" from an "s".  There
> are also significant intelligibility cues in the 20-80Hz range for
> some consonants.
> 300-3000 hz was convenient for the phone company and was proselytized
> by Collins (which we all know is never incorrect in design philosophy)
> as the gospel truth.  But it  contributed mostly to Uncle Bob and
> Granny being so hard to understand and sounding so lousy on the
> telephone.  And contributes still to "pinched" sounding radios.  Your
> modern telephone (fortunately) exceeds this old accepted range in
> bandwidth.
> Grant/NQ5T
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