[sci.electronics] Multiple AM Stereo Receivers

klopfens@bgsuvax.UUCP (Bruce Klopfenstein) (04/25/89)

While it is true that an AM stereo radio was possible which would
receive any of the competing AM stereo systems, my understanding is 
that such receivers would have cost at least $200 (I can check the
NTIA report--one of them--to se for sure).  Since the general public
(especially audiophiles) are not into AM radio anyway, how realistic
would it be for them to spend that amount of money for an AM radio?

The FCC's decision *not* to set a standard set up the classic chicken-
and-egg scenario: radio stations were reluctant to install a system
that might be made obsolete and receiver manufacturers were unwilling
to market AM stereo receivers until there were some "critical mass"
of AM stereo stations operating.

I don't know how it can be argued that AM stereo wouldn't make a
difference.  We just don't know.  Too few people ever 1) had access to
AM stereo in their markets and 2) had a receiver that would pick up
the appropriate signal.

-- 
Dr. Bruce C. Klopfenstein      |  klopfens@andy.bgsu.edu
Radio-TV-Film Department       |  klopfenstein@bgsuopie.bitnet
Bowling Green $tate University |  klopfens@bgsuvax.UUCP
Bowling Green, OH  43403       |  (419) 372-2138; 352-4818

dya@unccvax.UUCP (York David Anthony @ WKTD, Wilmington, NC) (04/25/89)

In article <4058@bgsuvax.UUCP>, klopfens@bgsuvax.UUCP (Bruce Klopfenstein) writes:
> While it is true that an AM stereo radio was possible which would
> receive any of the competing AM stereo systems, my understanding is 
> that such receivers would have cost at least $200 (I can check the
> NTIA report--one of them--to se for sure).  Since the general public
> (especially audiophiles) are not into AM radio anyway, how realistic
> would it be for them to spend that amount of money for an AM radio?

	This is pure hogwash (the price, that is).  I have both the
Sony SRF-A100 (the multimode table radio, AM-FM, $59.95) and the
Sony XR33-A (the multimode car stereo, AM-FM-stereo cassette, about
$140).  Both are wideband.

	No one seems to have a problem turning out C-QUAM receivers
by the zillions, and you can buy (from Leonard Kahn, no less) a retrofit
board which converts the Motorola C-QUAM chip into multimode.  It
is important to note that the C-QUAM chip is the subject of ongoing
litigation between Kahn and Motorola (patent infringment, among
other things).

	The **incremental cost** for stereo is very low, since you
have to provide the same front end that you do for mono.  In point
of fact, the C-QUAM decoder provides envelope detection for monaural
which you had to have anyway. (Actually, synchronous detection is
much better for the sum channel/monaural, another strike against
C-QUAM).

	As for suitable wideband IF amplifiers (where the locus of
the AM problem really resides) suitable monolithic ceramic filters
cost pennies in quantity.  I keep getting these rent-a-cars with
wideband IF amps (Toyota, Lincoln, Cadillac) so the inclusion 
must not be terribly expensive.

	Let's move this out of rec.ham-radio, BTW.....

York David Anthony
WKTD Wilmington, NC

rfc@briar.philips.com (Robert Casey;6282;3.57;$0201) (04/26/89)

I'm probably the only listener in the NYC area [ :-) ] who owns a stereo AM
radio.  But there's nothing worth listening to (no music to speak of, I mean
any music, trying not to make my musical tastes enter the picture).  There's a
all news station that is in stereo, but what's the point of that?  Also, the
interference (powerline crud from florescent lights, etc) makes FM more
attractive.  In Australia, they seem to have a more healthy AM industry, maybe
because they did pick a standard (maybe a bad choice, but it *was* a choice)
and they did it before thier AM started to die.  There was powerline crud
there, but not as bad isain USA.