"ralph sansbury" writes:
1)Re error: Craig,you say that the received frequency power in
the FFT diagram is centered on the specific frequency of the
local oscillator frequency that most closely matches in phase and
frequency the received frequency. You say it is by eyeball
estimation about 15 to 20db above the values at other
frequencies.

No, I did not say that. I said that there was a carrier peak with
some breadth, bracketed by an overall noise level. I did not say
anything about a local oscillator, or phase. The centering of the
peak is merely a plotting convenience.

The FFT is an unbiased method for estimating the signal power at many
frequencies simultaneously, not just a local oscillator frequency.
For purposes of measuring signal strength, the FFT is just fine. For
more detailed radiometric tracking, of course the phase must be
tracked, which is why the cycle counters are used.

So, Craig, George, Is it unnecessary to reconcile this error
estimate with the difference between the recieved oscillations of
voltage and the oscillations produced by a local oscillator at a
specifc rms amplitude at the selected frequency made to match
most closely in phase the received oscillations and then modified
in frequency to maintain the close match?

This is a nonsensical paragraph. The FFT power density spectrum is
not an error estimate, therefore the remainder of your question is
irrelevant. Please keep this straight: the noise level is completely
separate from the modeling error in the tracking analysis.

Perhaps so. But what about the degree of correspondence of zero
crossings in the selected in phase local oscillator sequence of
oscillating voltages and the corresponding sequence of zero
crossings in the reduced(intermediate)representation of the
received frequency?
I should think that this would be indicative of the
reliability of the 'detected' frequency and phase given to the
local oscillator and would have some relationship to the 100db
Sig/Noise or whatever indicated FFT frequency with the most
power.??

The signal to noise level does indeed determine how well the Doppler
cycle count (= phase) can be tracked. But that's nothing new, from a
signal processing perspective. The Doppler cycle count technique does
*not* require an exact correspondence between the reference signal
(the local oscillator) and the received signal. It is the difference
between these two signals which is accumulated in the counter, and
then recorded for later analysis. There is enough information to
reconstruct the received "sky" frequency from that.


2)Re transmitted frequency: For the nth time where is the
transmitted frequency or is this just something you make up to
give the predicted Doppler result assuming the speed of light
delay?

And, for the N+1th time, the transmitted frequencies are recorded and
stored with the Doppler count data as special "ramp" records, with
timestamps. Again, you appear to be failing to pay attention.


3)Re received frequencies.In the tracking data logical record,
item 31 and 32 gives Doppler Count in units of 1000 time the
number of cycles. I gather this corresponds to Craig's Doppler
count which is instead in units of cycles.
What item gives the FSKY minus 2292000000Hz?

Perhaps it is the output of my own program, which George may have sent
to you. The "sky" frequency is computed in accord with the
recommendations of Moyer (2000), or Morabito & Asmar (1994).
Subtraction of 2.292 GHz is to avoid printing the same digits over and
over again, it's as simple as that.


4)re p6 of DSN 810-005 Rev.E/202,Rev.A
"The uplink carrier frequency is synthesized with the exciter
..... [at the receiver site] ...The uplink carrier may be either
constant or varied in accord with a tuning plan. In either case,
the phase of the[synthesized] uplink carrier is recorded for use
in the computation of a Doppler effect."
This sounds to me like the transmitted frequency at the
assumed transmission site is simulated at the receiver site and
used in computing the expected frequency.

What it sounds to you is irrelevant. Uplink and downlink sessions can
overlap -- but not always -- so it is natural to have a single
reference signal, in this case from the uplink exciter. All of the
Pioneer 10 uplinks were done at a constant transmitter frequency. The
downlinks, on the other hand, will have the Doppler signatures of
earth rotation and spacecraft motion imprinted on them. The uplink
synthesizer cannot mimic these. Indeed, the synthesizer is used only
as a reference frequency for Doppler counting. What the reference
frequency actually is, is irrelevant (as long as it's within the
counter's bandpass).

The comparison to a "predicted" frequency only happens hours, months
or years later when the tracking analysis is performed in software.


5)Thus unless it is possible to determine the transmit
frequency at the receiving site it will not be possible to test
the hypothesis that light speed does not extrapolate beyond 1
second(ie beyond r for r/c1). If the transmit frequency at the
receiving site is known to be the same as the transmit frequency
at the assumed site then of course it would be possible to test
this hypothesis.

The transmitted frequency is determined by solving the light travel
time equations. Fortunately, there is only one solution trajectory
(within an extremely tight confidence region) which agrees with the
data. As I have mentioned several times in the past, changing the
speed of light by even one part in one million ,destroys any possible
solution. Therefore your supposition is completely erroneous.

Your phrase, "transmit frequency at the receiving site" is
nonsensical. *IF* the uplink transmitter is operating at the
receiving site, it would be for the *next* session, not the current
one.

Furthermore, you have been provided with many examples where the
receiving station is completely blocked from the line to the
spacecraft when the uplink occurs, or the transmitting station is
blocked when the downlink occurs. In fact, blockage is far more
common than not.

I am aware that you claim that somehow the transmitter's uplink signal
is misinterpretted as the same station's downlink. But that ignores
some very obvious and fatal issues like: if it were true, how do the
signatures of spacecraft and earth motion get imprinted on the signal?
(they wouldn't) or, how does *ANY* spacecraft telemetry get detected
on the signal? (it wouldn't be) or, what happens when uplink and
downlink are not always overlapping? (your supposition would be
false) or, how could any spacecraft be successfully navigated? (they
couldn't be) And finally, how could the uplink be mistaken as the
downlink when they are separated by over 200 MHz in frequency? (they
couldn't be mistaken) Your supposition is completely and utterly
unfounded.

CM