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Craig Markwardt says re the doppler data tapes from Pioneer:
" For the uplink frequency, it appears that fields 113-114, programmed start frequency, should be used. This is the frequency of a programmable digital oscillator (DCO), which is then fed to the transmitter/exciter and multiplied by 96. The documentation I have says that the DCO frequency should be near 24 MHz, however, the values printed in fields 113-114 appear to be about twice that value, or 48 MHz. To make the output be S-band, ~2.2 GHz, the multiplier should be 48 and not 96. I have some reduced data from Anderson et al's reduction of the Pioneer data, and they use the DCO frequency, and not the value in field 116, which is the transmitter/exciter frequency. Part of the reason to avoid field 116 is that it is low precision." So the question is how reliable are the differences in frequencies that Anderson et al use to make their point about an anomalous acceleration caused by a Kuiper belt object or a change in the curvature of space time or whatever? |
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![]() "ralph sansbury" writes: Craig Markwardt says re the doppler data tapes from Pioneer: " For the uplink frequency, it appears that fields 113-114, programmed start frequency, should be used. This is the frequency of a programmable digital oscillator (DCO), which is then fed to the transmitter/exciter and multiplied by 96. The documentation I have says that the DCO frequency should be near 24 MHz, however, the values printed in fields 113-114 appear to be about twice that value, or 48 MHz. To make the output be S-band, ~2.2 GHz, the multiplier should be 48 and not 96. I have some reduced data from Anderson et al's reduction of the Pioneer data, and they use the DCO frequency, and not the value in field 116, which is the transmitter/exciter frequency. Part of the reason to avoid field 116 is that it is low precision." So the question is how reliable are the differences in frequencies that Anderson et al use to make their point about an anomalous acceleration caused by a Kuiper belt object or a change in the curvature of space time or whatever? After posting the web page you refer to, I received some information from a radio science expert which explained the issue. Over the years the components of the DSN have been upgraded. Early systems in the 70s used a voltage controlled oscillator (VCO) with a multiplier of 96 (~22 MHz x 96). When digital controlled oscillators (DCOs) were introduced, the multiplier was changed to 48 (~44 MHz x 48). Thus, both multipliers were in use, but in different eras. The 48 value is correct for the data I analyzed. As I mentioned, it's also quite obvious from the data values in the ATDF records. For the transmitter system to be operating near 2.2 GHz, which it does, the DCO frequency multiplier must be 48. As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Second, the tracking data are highly sensitive to such external factors. If one varies the speed of light by even a few parts in million, then the tracking solution is severely degraded. The quality of the data are so good that there is really no room for personal subjective choice on these matters. CM |
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![]() Hi Craig, Re the transmitter frequency subtracted from the received frequency to the get the doppler shift and motion of Pioneer 10 relative to the earth at any specific time. If the multiplier is exactly 48 for the DCOcase but 96 earlier and this corresponds to something specific in the phyical circuit, that would be ok. (What does it correspond to?) But it sounded like you were saying the multiplier might have been chosen simply because it gave a value near the predicted value and that 47.9 or 49.1 etc would not do so. And then the reliability of the data would be based on the theory it was supposed to confirm. Or maybe the multiplier had to be an integer because this is the nature of the corresponding circuit?? A brief description of this etc would be helpful. It was very helpful to find out the reason for the change from 96 to 48. You say As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Exactly and that is my question???? If the milliHz terms supposedly used to show a small anomalous acceleration would have been changed by using a different multiplier and there is no independent reason for choosing 48 or 48.1 etc, then there is a problem!!!! Another problem is how do we know the transmitter frequency was always exactly the same as the frequency produced by the DCO times 48? Ralph Sansbury ----- Original Message ----- From: "Craig Markwardt" To: "Ralph Sansbury" Cc: ; "George Dishman" Sent: Saturday, November 08, 2003 2:32 PM Subject: Pioneer data tape question Ralph Sansbury writes: Craig, In one of your papers you say: "For the uplink frequency, it appears that fields 113-114, programmed start frequency, should be used. This is the frequency of a programmable digital oscillator (DCO), which is then fed to the transmitter/exciter and multiplied by 96. The documentation I have says that the DCO frequency should be near 24 MHz, however, the values printed in fields 113-114 appear to be about twice that value, or 48 MHz. To make the output be S-band, ~2.2 GHz, the multiplier should be 48 and not 96. I have some reduced data from Anderson et al's reduction of the Pioneer data, and they use the DCO frequency, and not the value in field 116, which is the transmitter/exciter frequency. Part of the reason to avoid field 116 is that it is low precision." This all sounds very vague and I wonder how reliable the resulting doppler shift could be. It appears you can use any multiplier you want to come as close as possible to the assumed predicted difference? Right? Mr. Sansbury-- Your presupposition is incorrect: one cannot use any multiplier one wants. The multiplier for the data I analyzed is 48. After posting the web page you refer to, I received some information from a radio science expert which explained the issue. Over the years the components of the DSN have been upgraded. Early systems in the 70s used a voltage controlled oscillator (VCO) with a multiplier of 96 (~22 MHz x 96). When digital controlled oscillators (DCOs) were introduced, the multiplier was changed to 48 (~44 MHz x 48). Thus, both multipliers were in use, but in different eras. The 48 value is correct for the data I analyzed. As I mentioned, it's also quite obvious from the data values in the ATDF records. For the transmitter system to be operating near 2.2 GHz, which it does, the DCO frequency multiplier must be 48. As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Second, the tracking data are highly sensitive to such external factors. If one varies the speed of light by even a few parts in million, then the tracking solution is severely degraded. The quality of the data are so good that there is really no room for personal subjective choice on these matters. CM "Craig Markwardt" wrote in message news ![]() "ralph sansbury" writes: Craig Markwardt says re the doppler data tapes from Pioneer: " For the uplink frequency, it appears that fields 113-114, programmed start frequency, should be used. This is the frequency of a programmable digital oscillator (DCO), which is then fed to the transmitter/exciter and multiplied by 96. The documentation I have says that the DCO frequency should be near 24 MHz, however, the values printed in fields 113-114 appear to be about twice that value, or 48 MHz. To make the output be S-band, ~2.2 GHz, the multiplier should be 48 and not 96. I have some reduced data from Anderson et al's reduction of the Pioneer data, and they use the DCO frequency, and not the value in field 116, which is the transmitter/exciter frequency. Part of the reason to avoid field 116 is that it is low precision." So the question is how reliable are the differences in frequencies that Anderson et al use to make their point about an anomalous acceleration caused by a Kuiper belt object or a change in the curvature of space time or whatever? After posting the web page you refer to, I received some information from a radio science expert which explained the issue. Over the years the components of the DSN have been upgraded. Early systems in the 70s used a voltage controlled oscillator (VCO) with a multiplier of 96 (~22 MHz x 96). When digital controlled oscillators (DCOs) were introduced, the multiplier was changed to 48 (~44 MHz x 48). Thus, both multipliers were in use, but in different eras. The 48 value is correct for the data I analyzed. As I mentioned, it's also quite obvious from the data values in the ATDF records. For the transmitter system to be operating near 2.2 GHz, which it does, the DCO frequency multiplier must be 48. As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Second, the tracking data are highly sensitive to such external factors. If one varies the speed of light by even a few parts in million, then the tracking solution is severely degraded. The quality of the data are so good that there is really no room for personal subjective choice on these matters. CM |
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![]() "ralph sansbury" writes: Hi Craig, Re the transmitter frequency subtracted from the received frequency to the get the doppler shift and motion of Pioneer 10 relative to the earth at any specific time. If the multiplier is exactly 48 for the DCOcase but 96 earlier and this corresponds to something specific in the phyical circuit, that would be ok. (What does it correspond to?) The hardware has a fixed integer multiplier between the reference oscillator and the transmitted frequency. For the VCO the multiplier was 96, for the DCO it was 48. This is not a tunable parameter, i.e. it is fixed exactly by the electronics and microwave components of the oscillator and amplifier. The "choice" of 48 vs. 96 comes in the modeling software. The multiplier in the software must match the multiplier used in the hardware. There is no subjective choice involved. You say As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Exactly and that is my question???? If the milliHz terms supposedly used to show a small anomalous acceleration would have been changed by using a different multiplier and there is no independent reason for choosing 48 or 48.1 etc, then there is a problem!!!! If the frequency computations were off by 1 GHz, there would have been no "solution" to begin with... But that is silly. The Doppler modulations due to the earth's motion and rotation are all imprinted on the signal, and are known to far better than 1 GHz, and are easily checked by inspection of the data. A 1 GHz error would be caught immediately. And, to reiterate, there is no fitting or tuning involved in the DCO multiplier. Another problem is how do we know the transmitter frequency was always exactly the same as the frequency produced by the DCO times 48? Because that is how the system was designed, tested and productively used for more than a decade. CM |
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In message , ralph sansbury
writes Hi Craig, Re the transmitter frequency subtracted from the received frequency to the get the doppler shift and motion of Pioneer 10 relative to the earth at any specific time. If the multiplier is exactly 48 for the DCOcase but 96 earlier and this corresponds to something specific in the phyical circuit, that would be ok. (What does it correspond to?) But it sounded like you were saying the multiplier might have been chosen simply because it gave a value near the predicted value and that 47.9 or 49.1 etc would not do so. And then the reliability of the data would be based on the theory it was supposed to confirm. Or maybe the multiplier had to be an integer because this is the nature of the corresponding circuit?? A brief description of this etc would be helpful. It was very helpful to find out the reason for the change from 96 to 48. You say As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Exactly and that is my question???? If the milliHz terms supposedly used to show a small anomalous acceleration would have been changed by using a different multiplier and there is no independent reason for choosing 48 or 48.1 etc, then there is a problem!!!! Am I right in thinking that having failed to impress anyone with your idea that Venus radar data is the result of choosing the right signal and throwing the rest away, you are now saying the same approach can be used for the Pioneer anomaly? Which are the spacecraft that are supposed to have failed because NASA did not allow for the speed-of-light delay? -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
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Thanks Craig for the clarification that the transmitter
frequency for all transmissions to Pioneer 10 was the same and produced by a circuit that multiplied 96 in the early days;48, later, times a very precise 24 MHz local oscillator frequency. And that this then could produce a very reliable difference in the received frequency and the transmitted frequency. Jonathan, My interest in this question is not to show that only data confirming some theoretical position is accepted and the rest is thrown away. But rather to understand how it was possible to detect such small changes in frequency and so such small changes in velocity of the spacecraft upon which the Pioneer anomolous acceleration was based. The process is impressive and fascinating as is the process of analysing the radar reflections over Earth-Venus distances. In the latter case the process permitted the possibility of choosing different starting times in the received voltage oscillations and choosing the starting time and sequence that was least random looking and most compatible with variations in delay due to surface variations as one might have expected. The process in this case as I understand it involved the representation of nanosecond voltage variations as a Fourier series with the largest weighted sine component of frequency around 2292MHz and the other sine components much smaller. The specific phase and frequency is detected using filters,Fast Fourier Transforms and Phase Locked Loops. And if you subtracted the received voltage values at each nanosecond or fraction of a nanosecond from those predicted by the detected frequency and phase, you would get a set of numbers that was normally distributed around zero indicating that these differences were noise. Of course if the component of frequency in the expected range has the same weight as those in other ranges then this would indicate that it too was noise also. If the sum of squares of the observed around a predicted set of values is as great as the sum of squares about the mean of the set of values then the predicted set of values is worthless and I suppose some sort of criteria is the basis for saying that the receptions from Pioneer 10 are now lost in noise. It would be nice to get a little more clarification on this point eg What is ratio of error sum of squares around the selected frequency to the sum of squares around the mean? "Jonathan Silverlight" wrote in message ... In message , ralph sansbury writes Hi Craig, Re the transmitter frequency subtracted from the received frequency to the get the doppler shift and motion of Pioneer 10 relative to the earth at any specific time. If the multiplier is exactly 48 for the DCOcase but 96 earlier and this corresponds to something specific in the phyical circuit, that would be ok. (What does it correspond to?) But it sounded like you were saying the multiplier might have been chosen simply because it gave a value near the predicted value and that 47.9 or 49.1 etc would not do so. And then the reliability of the data would be based on the theory it was supposed to confirm. Or maybe the multiplier had to be an integer because this is the nature of the corresponding circuit?? A brief description of this etc would be helpful. It was very helpful to find out the reason for the change from 96 to 48. You say As for the reliability, I can quote two results. First, the frequency residuals from my solution (or Anderson et al's solution) are of order *milli*Hertz, which is a few parts in a million million of the baseband frequency. A factor of two problem in the baseband frequency would result in errors of order gigahertz. Exactly and that is my question???? If the milliHz terms supposedly used to show a small anomalous acceleration would have been changed by using a different multiplier and there is no independent reason for choosing 48 or 48.1 etc, then there is a problem!!!! Am I right in thinking that having failed to impress anyone with your idea that Venus radar data is the result of choosing the right signal and throwing the rest away, you are now saying the same approach can be used for the Pioneer anomaly? Which are the spacecraft that are supposed to have failed because NASA did not allow for the speed-of-light delay? -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
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In message , ralph sansbury
writes Jonathan, My interest in this question is not to show that only data confirming some theoretical position is accepted and the rest is thrown away. But rather to understand how it was possible to detect such small changes in frequency and so such small changes in velocity of the spacecraft upon which the Pioneer anomolous acceleration was based. The process is impressive and fascinating as is the process of analysing the radar reflections over Earth-Venus distances. In the latter case the process permitted the possibility of choosing different starting times in the received voltage oscillations and choosing the starting time and sequence that was least random looking and most compatible with variations in delay due to surface variations as one might have expected. The process in this case as I understand it involved the representation of nanosecond voltage variations as a Fourier series with the largest weighted sine component of frequency around 2292MHz and the other sine components much smaller. The specific phase and frequency is detected using filters,Fast Fourier Transforms and Phase Locked Loops. And if you subtracted the received voltage values at each nanosecond or fraction of a nanosecond from those predicted by the detected frequency and phase, you would get a set of numbers that was normally distributed around zero indicating that these differences were noise. Of course if the component of frequency in the expected range has the same weight as those in other ranges then this would indicate that it too was noise also. Instead of posting your nonsense here, why not try contacting the various groups who have been mapping Venus by radar since the 1960s? You will have quite a choice - Arecibo, the Russians, the Pioneer Venus team, and the Magellan team have all produced similar results from very different equipment. I also pointed you toward mapping of asteroids such as Kleopatra. -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
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Thanks Craig for the clarification that the transmitter
frequency for all transmissions to Pioneer 10 was the same and produced by a circuit that multiplied 96 in the early days;48, later, times a very precise 24 MHz local oscillator frequency. And that this then could produce a very reliable difference in the received frequency and the transmitted frequency. The process in this case as I understand it involved the representation of nanosecond voltage variations as a Fourier series with the largest weighted sine component of frequency around 2292MHz and the other sine components much smaller. The specific phase and frequency is detected using filters, Fast Fourier Transforms and Phase Locked Loops. And if you subtracted the received voltage values at each nanosecond or fraction of a nanosecond from those predicted by the detected frequency and phase, you would get a set of numbers that was normally distributed around zero indicating that these differences were noise. Of course if the component of frequency in the expected range has the same weight as those in other ranges then this would indicate that it too was noise also. If the sum of squares of the observed around a predicted set of values is as great as the sum of squares about the mean of the set of values then the predicted set of values is worthless and I suppose some sort of criteria is the basis for saying that the receptions from Pioneer 10 are now lost in noise. It would be nice to get a little more clarification on this point eg What is ratio of error sum of squares around the selected frequency to the sum of squares around the mean? Does item 101 Average Doppler Residual have something to do with the numerator of this ratio eg 3 times the sq rt of numerator would lead to a 99percent confidence interval for the true received doppler shift? Ralph Sansbury "Craig Markwardt" wrote in message news ![]() "ralph sansbury" writes: Hi Craig, Re the transmitter frequency subtracted from the received frequency to the get the doppler shift and motion of Pioneer 10 relative to the earth at any specific time. If the multiplier is exactly 48 for the DCOcase but 96 earlier and this corresponds to something specific in the phyical circuit, that would be ok. (What does it correspond to?) The hardware has a fixed integer multiplier between the reference oscillator and the transmitted frequency. For the VCO the multiplier was 96, for the DCO it was 48. This is not a tunable parameter, i.e. it is fixed exactly by the electronics and microwave components of the oscillator and amplifier. The "choice" of 48 vs. 96 comes in the modeling software. The multiplier in the software must match the multiplier used in the hardware. There is no subjective choice involved. Exactly and that is my question???? If the milliHz terms supposedly used to show a small anomalous acceleration would have been changed by using a different multiplier and there is no independent reason for choosing 48 or 48.1 etc, then there is a problem!!!! And, to reiterate, there is no fitting or tuning involved in the DCO multiplier. Another problem is how do we know the transmitter frequency was always exactly the same as the frequency produced by the DCO times 48? Because that is how the system was designed, tested and productively used for more than a decade. |
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![]() "Jonathan Silverlight" wrote in message ... In message , ralph sansbury writes Jonathan, My interest in this question is not to show that only data confirming some theoretical position is accepted and the rest is thrown away. But rather to understand how it was possible to detect such small changes in frequency and so such small changes in velocity of the spacecraft upon which the Pioneer anomolous acceleration was based. The process is impressive and fascinating as is the process of analysing the radar reflections over Earth-Venus distances. In the latter case the process permitted the possibility of choosing different starting times in the received voltage oscillations and choosing the starting time and sequence that was least random looking and most compatible with variations in delay due to surface variations as one might have expected. This method was completely different than the method involved in digging signal out of noise in the spacecraft doppler case. The process in this Pioneer 10 case as I understand it involved the representation of nanosecond voltage variations as a Fourier series with the largest weighted sine component of frequency around 2292MHz and the other sine components much smaller. The specific phase and frequency is detected using filters,Fast Fourier Transforms and Phase Locked Loops. And if you subtracted the received voltage values at each nanosecond or fraction of a nanosecond from those predicted by the detected frequency and phase, you would get a set of numbers that was normally distributed around zero indicating that these differences were noise. Of course if the component of frequency in the expected range has the same weight as those in other ranges then this would indicate that it too was noise also. Instead of posting your nonsense here, why not try contacting the various groups who have been mapping Venus by radar since the 1960s? You will have quite a choice - Arecibo, the Russians, the Pioneer Venus team, and the Magellan team have all produced similar results from very different equipment. I also pointed you toward mapping of asteroids such as Kleopatra. -- I have. And unlike you they know something about the process that was used to derive radar maps from very weak radar reflections as opposed to less questionable radar maps from stronger radar reflections. There is reason to question the weaker signals and the method used to dig them out of noise see http://www.bestweb.net/~sansbury. The method can sometimes be valid but it can be stretched to point where legitimate questions can be raised as to the validity of the results. This applies to the earth venus case. I think you, or someone like you said that the earth venus reflections were compared with the spacecraft venus reflections eg pixel by pixel and the original noisy radar map was shown to be an accurate representation of the more believable spacecraft map. But that is baloney and you both know it. |
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In message , ralph sansbury
writes "Jonathan Silverlight" wrote in message ... Instead of posting your nonsense here, why not try contacting the various groups who have been mapping Venus by radar since the 1960s? You will have quite a choice - Arecibo, the Russians, the Pioneer Venus team, and the Magellan team have all produced similar results from very different equipment. I also pointed you toward mapping of asteroids such as Kleopatra. -- I have. And unlike you they know something about the process that was used to derive radar maps from very weak radar reflections as opposed to less questionable radar maps from stronger radar reflections. There is reason to question the weaker signals and the method used to dig them out of noise see http://www.bestweb.net/~sansbury. The method can sometimes be valid but it can be stretched to point where legitimate questions can be raised as to the validity of the results. This applies to the earth venus case. I think you, or someone like you said that the earth venus reflections were compared with the spacecraft venus reflections eg pixel by pixel and the original noisy radar map was shown to be an accurate representation of the more believable spacecraft map. But that is baloney and you both know it. I didn't say "pixel by pixel" or if I did, I overstated it. The first maps of Venus were more crude than the first pictures of the far side of the Moon. But they did show Alpha Regio and Beta Regio, where all subsequent studies have shown them with increasing detail. But I did make one mistake. The first work by R M Goldstein and S Zohar of JPL was done at Goldstone; the Arecibo results are good enough to compare directly with Magellan. See http://photojournal.jpl.nasa.gov/catalog/PIA00207, for instance. I don't see anything on your web page about radar or signal processing. -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
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