Subject: [removed] Digest V2005 #298
From: [removed]@[removed]
Date: 9/30/2005 5:06 AM

To: [removed]@[removed]

    ------------------------------

                                The Old-Time Radio Digest!
                                  Volume 2005 : Issue 298
                             A Part of the [removed]!
                                 [removed]
                                     ISSN: 1533-9289

                                     Today's Topics:

      AM Audio Frequency Response           [ "MICHAEL BIEL" <mbiel@[removed]; ]
      AM Audio Frequency Response           [ "MICHAEL BIEL" <mbiel@[removed]; ]
      Dylan and Kerouac                     [ <cooldown3@[removed]; ]
      Patrick wrote about Bob Dylan         [ <cooldown3@[removed]; ]

    ------------------------------

    Date: Thu, 29 Sep 2005 23:30:49 -0400
    From: "MICHAEL BIEL" <mbiel@[removed];
    To: [removed]@[removed]
    Subject:  AM Audio Frequency Response

    B Ray again claims :

>     the stations on the AM band were still limited to their 10 KHz
>     bandwidth, with an effective modulation limit of 5 KHz.

    and posted a bit of current regulation to try to prove it.  However,
    without his meaning to, these regulations actually confirm that AM audio
    frequency response is still allowed up to 10 KHz.  Additionally, if one of
    the later subparts had been included it would have also proved exactly what
    I had said, that "during the OTR years there never was any limit to the
    audio high frequency response of AM radio, either legal or technical."  You
    see, I was specifically not referring to the current situation.  The rules
    he cites did not become effective until the 1990s.  The effective dates are
    contained in subpart (e) which he did not include in his posting.   Prior
    to that time -- including the OTR years -- there was no upper limit to
    audio frequency transmission on AM transmission.

    Even now, as the rules he posted state, audio signals do not have to be
    attenuated until they hit 10,200 KHz.  The key phrase is "REMOVED FROM THE
    CARRIER", and it is apparent that the meaning of this phrase is not being
    properly understood.  The "carrier" is the unmodulated signal which sits on
    the assigned frequency.  "Removed" means how far the modulation deviates
    from the assigned frequency in each direction separately, not the total
    distance from the lower sideband to the higher sideband.

    Let's see what this means in practice.  Lets say we are considering WLW
    which is assigned to a carrier frequency of 700 KHz. on your dial.
    Because, as was stated, AM broadcasting is Double Sideband, once the
    carrier is modulated with audio it will cause the signal to take up the
    space both above and below the assigned carrier frequency that equals the
    audio frequencies.  A 1 KHz. tone will show up 1 KHz. above and 1 KHz below
    the assigned carrier frequency.  In other words, these modulations are "1
    KHz. removed from the carrier".  On WLW that takes up space from 699,000
    Hz. to 701,000 Hz., or 699 KHz. to 701KHz.  An audio signal that had a high
    frequency limit of 5 KHz. will take up the space between 695 and 705 KHz.,
    and the upper and lower frequencies of this audio is "5 KHz. removed from
    the carrier".    Now, [removed] would have you believe that this is the limit
    of what is allowable, because over in New Jersey is a transmitter for WOR
    New York at the first-adjacent assignment 710 KHz. which is filling up the
    space between 705 and 715 KHz.  And there are also stations down on 690
    filling the space between 685 and 695.  BUT, look at the rule again.  It
    says that the attenuation (or reduction) of the modulation only need start
    at "[removed] KHz removed from the carrier".  That is an audio signal just above
    a 10 KHz. frequency response.  Stations ARE allowed to modulate audio that
    does seem to exceed the assigned channel onto the first-adjacent channel.
    Here's the important part of that regulation again:

    PART 73_RADIO BROADCAST SERVICES--
    Subpart A_AM Broadcast Stations
    Sec. [removed] AM transmission system emission limitations.
    	(b) Emissions [removed] kHz to 20 kHz removed from the carrier must
    		be attenuated at least 25 dB below the unmodulated
    		carrier level, emissions 20 kHz to 30 kHz removed
    		from the carrier must be attenuated at least 35 dB
    		below the unmodulated carrier level, emissions
    		[etc. etc.]

    This regulation was devised by the National Radio Systems Committee (NRSC)
    which was formed in the mid-1980s by the National Association of
    Broadcasters (NAB) and the Electronic Industries Association (EIA) [later
    the  Consumer Electronics Association (CEA), now Consumer Electronics
    Manufacturers Association (CEMA)] to encourage radio manufacturers to make
    radios with wider audio bandwidth by having stations reduce their high
    audio frequencies that were showing up as interference between
    SECOND-adjacent channels in the more and more crowded AM band.  The NRSC
    devised this plan between 1985 and 1987 and submitted it to the FCC, hoping
    the FCC would adopt it as mandatory regulation.  But those were the Reagan
    years, and all the FCC would do was allow the NRSC to make the rules
    voluntary.   Although the specs were published in June/July 1988, very
    little happened because stations were reluctant to reduce their high
    frequencies -- which they needed to push through the lousy radios being
    made at the time -- without assurance that their competitors would also
    reduce their high frequencies.  The Bush Sr. FCC was more reasonable, and
    they instituted rulemaking which instituted these guidelines into law in
    two steps.  A less stringent set of rules, NRSC-1, would go into effect
    June 30, 1990, and the full set of rules as posted yesterday, NRSC-2,  went
    into effect on June 30, 1994.

    Let me quote from several NRSC publications from 1988 which are still
    available on the web at
    [removed]

    "On January 10, 1987, the NRSC authorized the NAB and the EIA to publish an
    interim voluntary national standard specifying AM preemphesis, AM
    deemphesis and a 10 kHz AM audio bandwidth.  The NRSC-1 audio standard
    applies to the audio signals that are intended to modulate the AM
    transmitter.  Its purpose is to reduce second-adjacent channel interference
    by band limiting AM stations to a nominal 20 kHz occupied radio-frequency
    (RF) bandwidth (twice the 10 kHz audio bandwidth presented to the
    transmitter's modulation circuits.)"

    "This document also describes a specification for the maximum audio
    bandwidth transmitted by AM broadcast stations.  Implementation of a
    bandwidth specification will reduce second-adjacent channel interference
    and thereby lead to (1) a significant reduction of second-adjacent channel
    interference as perceived on 'wideband' AM receivers; (2) a corresponding
    increase in the interference-free service areas of AM stations; and (3) an
    incentive for the further building of dual bandwidth AM 'wideband'
    receivers. (Footnote -- First Adjacent channel interference considerations
    may continue to discourage the building of single bandwidth 'wideband'
    receivers; however, the extent of this form of interference has not been
    fully studied by the NRSC.)  Analysis by a subgroup of the NRSC has shown
    that there would be little if any detrimental effect on today's
    'narrowband' AM receivers upon the implementation of this voluntary
    standard."

    When you have a narrowband radio or set a dual bandwidth radio to narrow,
    the audio above 4 or 5 KHz is not detected, thus it does not present
    audible interference between first-adjacent stations.  If there isn't a
    strong first adjacent station sitting next to the station you are listening
    to, you can set the radio to wide and hear the audio frequencies that
    potentially can extend up to 7, 8, and 9 or so KHz.  Indeed, the second
    document quoted, "NRSC AM Preemphasis/Deemphasis and Broadcast Audio
    Transmission Bandwidth Specifications" shows on page 2 a preemphesis curve
    that increases the audio strength of the high frequencies between 1 KHz. to
    10 KHz.  The audio starts to rise at about 500 Hz so that it is about 1 dB
    louder at 1 KHz. and then continues upwards so that at 10 KHz it is 10 dB
    louder.  And then, as stated in the law above, there has to be a filtering
    to bring the audio down to minus 25 dB. at [removed] KHz.

    Thus, even today, AM radio stations are allowed to have an audio bandwidth
    of 10 KHz.  It is the second-adjacent channel that the FCC rules are
    designed to protect, and in our case of WLW Cincinnati we would be
    including WGN Chicago at 720.   And as I have said before, prior to 1990
    and back through the OTR era, AM stations did not have even that top
    limitation to their audio frequency response, and transmitters could often
    exceed 10 KHz. even in the early 30s, and routinely got above 13 or 14 KHz.
    by the 1950s.

    The problems arose when the band became more crowded in the 1960s with
    stations much closer together geographically and on the band.
    Second-adjacent interference became much more common than in the OTR era,
    and first-adjacent interference caused many radio manufacturers to start
    limiting audio bandwidth without an option to allow the user to switch the
    limitation off when there was no interference problem.  Because most
    magazine equipment reviews only measured FM audio quality and gave a pass
    on the AM circuits, very few consumers knew how lousy AM radios were
    becoming.  They thought AM radio sounded lousy, not realizing it was their
    radio's fault, not the fault of the stations.  Even I had not realized it
    was happening.  I had been using two wonderful Sony multi-band sets from
    the mid 60s for many years and was SHOCKED when I replaced them with
    another Sony multiband in 1983 that had no AM audio bandwidth at all.  But
    several years later when AM-Stereo was introduced, for a brief time Sony
    produced several wideband AM Stereo sets, and these are so good that before
    NRSC bandwidth limitation was implemented, on a good station it was hard to
    tell the difference between AM and FM except for the noise.    Indeed, thru
    the use of the preemphesis curve, NRSC had the goal of bringing AM sound
    back to those standards despite the 10 KHz response limitation by
    encouraging the building of better receivers.  The NRSC-1 document states:
    "It is the goal of the NRSC to increase the fidelity of the AM transmission
    and reception system from its present state to a quality level that
    approaches the quality available via FM broadcasting."

    In the [removed] a 5 KHz audio frequency response limitation for AM radio is a
    MYTH and always was totally untrue.  There might be some limitations
    overseas where the channels are separated by 9 KHz, but that was never an
    issue in this discussion.

    Michael Biel   mbiel@[removed]

    ------------------------------

    Date: Thu, 29 Sep 2005 23:33:03 -0400
    From: "MICHAEL BIEL" <mbiel@[removed];
    To: [removed]@[removed]
    Subject:  AM Audio Frequency Response

    B Ray again claims :

>     the stations on the AM band were still limited to their 10 KHz
>     bandwidth, with an effective modulation limit of 5 KHz.

    and posted a bit of current regulation to try to prove it.  However,
    without his meaning to, these regulations actually confirm that AM audio
    frequency response is still allowed up to 10 KHz.  Additionally, if one of
    the later subparts had been included it would have also proved exactly what
    I had said, that "during the OTR years there never was any limit to the
    audio high frequency response of AM radio, either legal or technical."  You
    see, I was specifically not referring to the current situation.  The rules
    he cites did not become effective until the 1990s.  The effective dates are
    contained in subpart (e) which he did not include in his posting.   Prior
    to that time -- including the OTR years -- there was no upper limit to
    audio frequency transmission on AM transmission.

    Even now, as the rules he posted state, audio signals do not have to be
    attenuated until they hit 10,200 KHz.  The key phrase is "REMOVED FROM THE
    CARRIER", and it is apparent that the meaning of this phrase is not being
    properly understood.  The "carrier" is the unmodulated signal which sits on
    the assigned frequency.  "Removed" means how far the modulation deviates
    from the assigned frequency in each direction separately, not the total
    distance from the lower sideband to the higher sideband.

    Let's see what this means in practice.  Lets say we are considering WLW
    which is assigned to a carrier frequency of 700 KHz. on your dial.
    Because, as was stated, AM broadcasting is Double Sideband, once the
    carrier is modulated with audio it will cause the signal to take up the
    space both above and below the assigned carrier frequency that equals the
    audio frequencies.  A 1 KHz. tone will show up 1 KHz. above and 1 KHz below
    the assigned carrier frequency.  In other words, these modulations are "1
    KHz. removed from the carrier".  On WLW that takes up space from 699,000
    Hz. to 701,000 Hz., or 699 KHz. to 701KHz.  An audio signal that had a high
    frequency limit of 5 KHz. will take up the space between 695 and 705 KHz.,
    and the upper and lower frequencies of this audio is "5 KHz. removed from
    the carrier".    Now, [removed] would have you believe that this is the limit
    of what is allowable, because over in New Jersey is a transmitter for WOR
    New York at the first-adjacent assignment 710 KHz. which is filling up the
    space between 705 and 715 KHz.  And there are also stations down on 690
    filling the space between 685 and 695.  BUT, look at the rule again.  It
    says that the attenuation (or reduction) of the modulation only need start
    at "[removed] KHz removed from the carrier".  That is an audio signal just above
    a 10 KHz. frequency response.  Stations ARE allowed to modulate audio that
    does seem to exceed the assigned channel onto the first-adjacent channel.
    Here's the important part of that regulation again:

    PART 73_RADIO BROADCAST SERVICES--
    Subpart A_AM Broadcast Stations
    Sec. [removed] AM transmission system emission limitations.
    	(b) Emissions [removed] kHz to 20 kHz removed from the carrier must
    		be attenuated at least 25 dB below the unmodulated
    		carrier level, emissions 20 kHz to 30 kHz removed
    		from the carrier must be attenuated at least 35 dB
    		below the unmodulated carrier level, emissions
    		[etc. etc.]

    This regulation was devised by the National Radio Systems Committee (NRSC)
    which was formed in the mid-1980s by the National Association of
    Broadcasters (NAB) and the Electronic Industries Association (EIA) [later
    the  Consumer Electronics Association (CEA), now Consumer Electronics
    Manufacturers Association (CEMA)] to encourage radio manufacturers to make
    radios with wider audio bandwidth by having stations reduce their high
    audio frequencies that were showing up as interference between
    SECOND-adjacent channels in the more and more crowded AM band.  The NRSC
    devised this plan between 1985 and 1987 and submitted it to the FCC, hoping
    the FCC would adopt it as mandatory regulation.  But those were the Reagan
    years, and all the FCC would do was allow the NRSC to make the rules
    voluntary.   Although the specs were published in June/July 1988, very
    little happened because stations were reluctant to reduce their high
    frequencies -- which they needed to push through the lousy radios being
    made at the time -- without assurance that their competitors would also
    reduce their high frequencies.  The Bush Sr. FCC was more reasonable, and
    they instituted rulemaking which instituted these guidelines into law in
    two steps.  A less stringent set of rules, NRSC-1, would go into effect
    June 30, 1990, and the full set of rules as posted yesterday, NRSC-2,  went
    into effect on June 30, 1994.

    Let me quote from several NRSC publications from 1988 which are still
    available on the web at
    [removed]

    "On January 10, 1987, the NRSC authorized the NAB and the EIA to publish an
    interim voluntary national standard specifying AM preemphesis, AM
    deemphesis and a 10 kHz AM audio bandwidth.  The NRSC-1 audio standard
    applies to the audio signals that are intended to modulate the AM
    transmitter.  Its purpose is to reduce second-adjacent channel interference
    by band limiting AM stations to a nominal 20 kHz occupied radio-frequency
    (RF) bandwidth (twice the 10 kHz audio bandwidth presented to the
    transmitter's modulation circuits.)"

    "This document also describes a specification for the maximum audio
    bandwidth transmitted by AM broadcast stations.  Implementation of a
    bandwidth specification will reduce second-adjacent channel interference
    and thereby lead to (1) a significant reduction of second-adjacent channel
    interference as perceived on 'wideband' AM receivers; (2) a corresponding
    increase in the interference-free service areas of AM stations; and (3) an
    incentive for the further building of dual bandwidth AM 'wideband'
    receivers. (Footnote -- First Adjacent channel interference considerations
    may continue to discourage the building of single bandwidth 'wideband'
    receivers; however, the extent of this form of interference has not been
    fully studied by the NRSC.)  Analysis by a subgroup of the NRSC has shown
    that there would be little if any detrimental effect on today's
    'narrowband' AM receivers upon the implementation of this voluntary
    standard."

    When you have a narrowband radio or set a dual bandwidth radio to narrow,
    the audio above 4 or 5 KHz is not detected, thus it does not present
    audible interference between first-adjacent stations.  If there isn't a
    strong first adjacent station sitting next to the station you are listening
    to, you can set the radio to wide and hear the audio frequencies that
    potentially can extend up to 7, 8, and 9 or so KHz.  Indeed, the second
    document quoted, "NRSC AM Preemphasis/Deemphasis and Broadcast Audio
    Transmission Bandwidth Specifications" shows on page 2 a preemphesis curve
    that increases the audio strength of the high frequencies between 1 KHz. to
    10 KHz.  The audio starts to rise at about 500 Hz so that it is about 1 dB
    louder at 1 KHz. and then continues upwards so that at 10 KHz it is 10 dB
    louder.  And then, as stated in the law above, there has to be a filtering
    to bring the audio down to minus 25 dB. at [removed] KHz.

    Thus, even today, AM radio stations are allowed to have an audio bandwidth
    of 10 KHz.  It is the second-adjacent channel that the FCC rules are
    designed to protect, and in our case of WLW Cincinnati we would be
    including WGN Chicago at 720.   And as I have said before, prior to 1990
    and back through the OTR era, AM stations did not have even that top
    limitation to their audio frequency response, and transmitters could often
    exceed 10 KHz. even in the early 30s, and routinely got above 13 or 14 KHz.
    by the 1950s.

    The problems arose when the band became more crowded in the 1960s with
    stations much closer together geographically and on the band.
    Second-adjacent interference became much more common than in the OTR era,
    and first-adjacent interference caused many radio manufacturers to start
    limiting audio bandwidth without an option to allow the user to switch the
    limitation off when there was no interference problem.  Because most
    magazine equipment reviews only measured FM audio quality and gave a pass
    on the AM circuits, very few consumers knew how lousy AM radios were
    becoming.  They thought AM radio sounded lousy, not realizing it was their
    radio's fault, not the fault of the stations.  Even I had not realized it
    was happening.  I had been using two wonderful Sony multi-band sets from
    the mid 60s for many years and was SHOCKED when I replaced them with
    another Sony multiband in 1983 that had no AM audio bandwidth at all.  But
    several years later when AM-Stereo was introduced, for a brief time Sony
    produced several wideband AM Stereo sets, and these are so good that before
    NRSC bandwidth limitation was implemented, on a good station it was hard to
    tell the difference between AM and FM except for the noise.    Indeed, thru
    the use of the preemphesis curve, NRSC had the goal of bringing AM sound
    back to those standards despite the 10 KHz response limitation by
    encouraging the building of better receivers.  The NRSC-1 document states:
    "It is the goal of the NRSC to increase the fidelity of the AM transmission
    and reception system from its present state to a quality level that
    approaches the quality available via FM broadcasting."

    In the [removed] a 5 KHz audio frequency response limitation for AM radio is a
    MYTH and always was totally untrue.  There might be some limitations
    overseas where the channels are separated by 9 KHz, but that was never an
    issue in this discussion.

    Michael Biel   mbiel@[removed]

    ------------------------------

    Date: Fri, 30 Sep 2005 00:22:08 -0400
    From: <cooldown3@[removed];
    To: [removed]@[removed]
    Subject:  Dylan and Kerouac

    Not the same thing.  Kerouaconly hurt himself.

    As towns all over america try to cash in on locals who made it, why do you
    think there is almost nothing there except a bar named after him? he came
    back for a relative's funeral a few years back and was not seen anywhere in
    public as I hear it.

    Great mind/ perhaps, but you would not say that if you were there.
    Cheers,
    patrick

    ------------------------------

    Date: Fri, 30 Sep 2005 07:01:13 -0400
    From: <cooldown3@[removed];
    To: [removed]@[removed]
    Subject:  Patrick wrote about Bob Dylan

    Hi Irene and all,

    I did not know him then in new York City, I had some traffic with him in
    Hibbing. I saw what I saw and was unimpressed with his ways.

    This does not take away from your experience but it could add to a more
    realistic view of the man.
    I am certainly glad you enjoyed his presence. Perhaps the confines of his
    circumstances were chafing him and leaving Hibbing was a good thing for him
    and for the music scene. I did not know him well enough to say that.

    Talent, he nad tons.

    How he treated others? ahhhh, That was the rub.

    I am sorry you find me petty. I was just being honest.

    Cheers,
    Patrick

    --------------------------------
    End of [removed] Digest V2005 Issue #298
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