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On 31 May 2006 03:15:44 -0500, Craig Markwardt
<craigmnet@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
>John C. Polasek <jpolasek@xxxxxxxxxx> writes:
>
>
>> On 30 May 2006 18:39:23 -0500, Craig Markwardt
>> <craigmnet@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> >John C. Polasek <jpolasek@xxxxxxxxxx> writes:
>> >
>> >
>> >> On 30 May 2006 14:34:28 -0500, Craig Markwardt
>> >> <craigmnet@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>> >> >John C. Polasek <jpolasek@xxxxxxxxxx> writes:
>> >...
>> >> >> As George said in his note above,
>> >> >> "The model was initialised in 1987 so at that time fmodel was set
>> >> >> equal to fobs."
>> >> >> The computer model clearly was so initialized as to time and
>> >> >> frequency. You can see there would be no motivationto readjust these.
>> >> >> ...
>> >> >
>> >> >You are incorrect. What was initialized in 1987 was the *trajectory*
>> >> >model. Each tracking uplink provides a self contained coherent
>> >> >frequency reference at the time of the session (not 1987). There are
>> >> >no variables in the solution program which store the frequency as it
>> >> >was in 1987.
>> >> If by trajectory you mean the orbital elements were determined in 1987
>> >> then, fine, but to produce actual ranges and velocities the
>> >> mathematical model has to include a good value of G to convert planet
>> >> distance into accelerations, to be integrated into real velocity. Then
>> >> to convert the velocity to frequency for comparison of Doppler phase
>> >> slippage, the program had to contain the multiplier f0/c as given in
>> >> Eq. 1 of Anderson, 10 Mar. 2005:
>> >[ note incorrect citation ]
>> >> delta f(t) = f0*(1/c)*dr/dt
>> >> The conversion of dr/dt to delta f uses f0/c. Are you trying to tell
>> >> me that on initiation of each 5-day batch, they caused a re-setting of
>> >> f0 to match the current clock? It does not seem likely. ...
>> >
>> >The equation you are citing is one that describes how DSN tracking
>> >works in generic terms, and does not contain all of the technical
>> >details. Still, if you had read the attached footnote (#38), you
>> >would have found that "nu_0" is the "reference frequency." In fact,
>> >the reference frequency is recorded at the moment of the tracking
>> >session (it is the frequency standard of the station), and *NOT* in
>> >1987. (see also eqn 13). It is not reset in "each 5-day batch,"
>> >because it is recorded in each and every downlink record! [ and
>> >several times per uplink. ] When will you get it into your head that
>> >there are no variables in the program that store the "frequency" as of
>> >1987?
>> >
>> >CM
>> Firstly, #38 explains once again, only that "our frequency/velocity
>> convention is backwards", a receding craft getting a blue shift that
>> takes a bit of getting used to, but OK. No information is transmitted
>> there.
>
>Incorrect. As noted above, it defines nu_0.
How tautologically droll. Note #38 says in effect, "let's call the the
transmitted frequency nu0, OK? and let's call the received frequency
nu, OK?, and now, pay attention, we will evaluate their difference
backwards, so don't get mixed up".
Notice that since Pioneer was a nearly constant 12km/s that nu - nu0
is approximately 94,000 hz but this delta nu is never discussed in the
literature. It is in fact converted to craft velocity via V = -lambda
x delta nu.
(References to Fig. 1 & 2 are in my paper at
http://www.dualspace.net/uploads/cosmoarxivnu3.pdf
Fig. 1 is a reproduction of the principle equation regarding Ap and
Fig. 2 is a plot of the frequency excess over a 7.5 year period
beginning in Jan. 1987. The span is ~19 AU and the signal time 2.63
hours. The paper derives "little Ap" as a valid metrical anomaly).
If you take the slope in Fig. 2, 1.5 Hz over 7.5 years, and scale it
to signal time (= 1/25000) then you would get a frequency increment
that would make the received frequency become 94,000.00006 Hz so the
beat frequency would be 0.00006Hz. How extract Ap from that? It takes
the years to make things observable. JP
>> How is the reference frequency transcribed into the coefficients of
>> the mathematical computer program? As I pointed out there needs to be
>> a reliable G and a dependable f0, and of the latter, there was no
>> motivation in 1987 to assert that f0 is anything but constant.
>
>Incorrect. As noted above, the reference frequency is measured during
>each tracking session.
You have to be specific, reference frequency of what? Of the radar
transmission? We all know that. It's nu0.
But we are neglecting another reference frequency, nu_87 that is built
into the model. Notice that all computation of Ap has to do with
nu_observ - nu_model or in other words nu_obs - nu87. The program
contains a "canned frequency" that is used throughout Fig. 2 to
determine delta f. JP
>> What I have berought to your attention that is new is f0 increasing
>> with time as f = f0(1+Ht), and when compared to the static value in
>> the model, a linearly increasing disprepancy reveals itself.
>
>Irrelevant, since there is no "static value in the model."
>
>> The values f0 and c have to be in the program with no impetus to
>> change f0. Of course the ref frequency "is recorded at the moment of
>> the tracking session". Please clarify: is there a laboratory event
>> that causes one to change the equation constants?
>
>Improper question, since the reference frequency is not a constant.
>
>> I am talking about the construction of the model, against which all
>> these readings are taken. Is f0 a custom value for each shot?
>
>Now you seem to be getting it. The uplink, downlink and reference
>frequencies are all recorded separately (and continuously for the
>latter two) during each tracking session, and used for analysis.
>There are *no* frequency "constants" stored from 1987.
The uplink is ftran, your precious reference frequency is a clock used
to stabilize ftran, they are the same and the downlink is frec. Of
course these are recorded with each shot.
But all Ap computations are with respect to another frequency, f87,
that has got to be in the computer model in order to convert the
derived velocities into frequencies, the factor f87/c. JP
>And, as I pointed out so many messages ago, your "drifting clock"
>model was attempted by Anderson et al (2002), but was simply not a
>good match to the combined set of Pioneers, Voyager, Ulysses, and
>Galileo.
As I pointed out if they adjusted the frequency to get agreement but
did not adjust the wavelength then the Doppler would be good, but the
range would be bad. Range is one more step from frequency.
The other vehicles firstly were subject to important jet dynamics as
well as being at very short ranges where solar radiation pressure was
as they say .888 correlated. Pioneer got going after 20 AU. JP
>>If you persist in your erroneous "constant frequency from 1987"
>supposition any further, then it's not really worth continuing the
>thread.
>
>CM
>
>
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