> > “The purpose of the easily recognized alterations was to diminish the
> > credibility of the loud interference on the Dictabelt which had an
> > indelible electronic signature of an intentional jamming of the radio
> > channel.”
>
> So now you think that the conspirators intentionally jammed the radio
> channel? Which one? Why not both? Kooky.
> And then they altered the tape to cover up evidence of their jamming?
> But the tape shows live recording on channel one so what were they
> covering up?
Get off your high horse, mister, and show us your work that identifies the
source of the loud interference on the Bowles tape of the Dictabelt. Did
you cross correlate the interference with engine sounds? I doubt that you
know the meaning of my last question.
By contrast, I systematically studied the spectra of the loud interference
and characterized the source as a wideband frequency modulation of audio.
This result coupled with the long term spectra changes identified the
source as a jammer that used one multivibrator to simultaneously amplitude
and frequency modulate another multivibrator. These circuits generated the
wideband frequency modulated audio whose dense spectrum could not be
filtered.
>
> > “I suspect that unknown persons made these alterations before the
> > alleged shots were added to the acoustic record and the story of the
> > stuck open microphone was invented. This amended approach bypassed the
> > embarrassing problem of explaining how official records were
> > altered.”
>
> So now you have a third layer with someone else adding real shots fired
> in Dealey Plaza? For what purpose? To mislead the public into thinking
> that 4 shots were fired in Dealey Plaza?
> Every time someone asks you a question about your theory you need to
> make it more complex.
I am not surprised that you ignore the highly confused discussion by BBN
on the effect of playing speed upon frequency and time as well as the
convoluted explanation of AGC and heterodynes by the Watson Research
Center. Candidly, I believe these topics ideas are over your head so I
elaborate for the benefit of readers.
Playing a wave file at half speed illustrates the error made by BBN.
http://hdblenner.com/thump_files/gotmailhalfspeed.wav
The half speed playing lowered the pitch of the voice and extended its
duration. So correcting these distortions requires multiplying the
frequency by two and multiplying the duration by one half, the reciprocal
of two. Now that is simple enough for even Anthony Marsh to understand.
However, BBN in their effort to cover the error made by those who added
real shots the acoustic record was compelled to adjust for playing speed
error by multiplying frequency and time by the same correction factor. I
quote the report by BBN.
Source: BB&N - 8HSCA, 110
http://history-matters.com/archive/jfk/hsca/reportvols/vol8/html/HSCA_Vol8_0057b.htm
“The tape-recording system was found to be about 5% slow, when the
time annotations were measured with a stopwatch (see Fig. 9).
Therefore, the apparent pitch of the tone would have a frequency of
(1.05) (420) = 441 Hz.”
Source: BB&N - 8HSCA, 75
http://history-matters.com/archive/jfk/hsca/reportvols/vol8/html/HSCA_Vol8_0040a.htm
“The time span between the onset of the first impulse pattern and the
onset of the fourth impulse pattern on the Channel 1 tape is 7.9 sec.
When corrected for the fact that the tape recorder was running about
5% too slowly, the real time span is 8.3 sec. ”
So there you have the proof that BBN attempted corrections by
multiplying frequency and time by the same 1.05-factor.
As for the Watson Research Center they described operation of an AM
receiver in order to explain the behavior of AGC and heterodynes on
the Bowles tape of the Dictabelt. I quote them.
Channel-I AGC
Most radio receivers have an AGC circuit at IF stage to maintain a
steady IF signal level at the detector or discriminator. If there is
a sudden increase in the RF signal (such as caused by switching on a
strong carrier). AGC acts rapidly to reduce the IF amplifier gain to
bring down the signal within acceptable limits. On the other hand if
there is sudden decrease (such as caused by switching off a strong
carrier) in the RF signal level, AGC acts more slowly to restore the
IF amplifier gain. This is a typical characteristics [sic] of an AGC
circuit: fast attenuation and slow recovery.
Channel-I Heterodynes
On Channel-I spectra, several narrow-band high-energy tones are
intermittently present for short durations. These tones are not on
Channel II. Also at the end of each tone. there is evident a sharp
drop in total Channel-I energy. This indicates some kind of AGC
(Automatic Gain Control) action.
These narrow-band tones are called heterodynes. They were generated
when another transmitter came on the radio channel, while the
transmitter with the stuck-open mike was transmitting. The
difference in their carrier frequencies resulted in the heterodynes.
If the second carrier is strong it should also activate the AGC action
in the IF (Intermediate Frequency) stage of the radio receiver.
The AGC action also affects the audio output level because of the drop
in overall gain of the system. Therefore, when a heterodyne begins, we
should expect a sudden drop in the recorded level of the signal picked
up by the stuck-open mike. And after the heterodyne ends, we should
expect a slow recovery in the audio signal to its original level. This
phenomenon is indeed observed in Channel-I spectra.
End of quotation.
The errors in the quoted paragraphs could fill a web page.
>
> > The contents of the Bowles tapes tell us how they were altered without
> > specifying who, where or when the changes were made. Now do you get it
> > or do you still think that signal analysis can answer everything
> > question that can raise?
>
> I don't get your illogic. You are talking garbage.
>
>
Smart people say dumb things when they have something to hide.
Personnel of BBN and the Watson Research Center were not exceptions to
this rule.
BBN found that the grassy knoll shot on the Bowles tape required the
wrong correction factor. So instead of declaring the Bowles tape a
counterfeit they pretended that the same 1.05-factor corrected by
frequency and time.
The Watson Research Center had similar and more readily recognized
problems with the heterodynes. My link, Five to One, scores a change
in playing speed that does not change the frequency and duration of
the same heterodynes. On a more technical point, the narrow band
characters of the heterodynes were inconsistent with generation from
at least one frequency modulated radio signal.
So both sides of the acoustic debate made their contributions toward
hiding the alterations of the acoustic records.
Herbert