Author Topic: Digitizing NASA data tapes  (Read 4155 times)

Offline apollo16uvc

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Re: Digitizing NASA data tapes
« Reply #30 on: February 11, 2019, 10:46:45 AM »
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Offline apollo16uvc

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Re: Digitizing NASA data tapes
« Reply #31 on: February 16, 2019, 03:34:46 PM »
Working on several update that should be a substantial resource of new information. An update on the Satellite tapes and Pioneer tapes.

Here is a preview of visualizing the magnetic tracks of an FR-100 and FR-600 tape:

https://youtu.be/I85-aZuupxM

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Offline apollo16uvc

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Re: Digitizing NASA data tapes
« Reply #32 on: February 28, 2019, 04:04:47 PM »
I have got great news on the new ESA tapes!

I have tested out three of the five tapes with a magnetic viewing solution, and all three clearly showed 7 tracks like the NASA tapes. This means they have not been degaused or overwritten with an audio recorder. The tracks look like raw telemetry, not computer tapes. One tape has a label that clearly says it came from a tracking station. I think we should be able to digitize these too eventually.

The tapes I have tested are:
TD-1 (Tape ID: 1117-09-08-B)
ESRO 1A (Tape ID: 800 645 08 10B)
HEOS A2 (Tape ID: 1115 06 11B)

I have made two videos on it in dutch.
First, a tutorial on how to make your town magnetic viewing solution.


And finally, a video where I visualize the magnetic tracks on 3 tapes:


I have attached some photos of the tracks to this message. I promise I will publish a big archive with detailed scans and photos of all ESA and NASA tapes currently in my possession.

I am interested to know if it is possible to determine the frequency of a signal by the macro photos, any ideas?

Best regards,
Niels.
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Offline apollo16uvc

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Re: Digitizing NASA data tapes
« Reply #33 on: March 01, 2019, 06:58:20 AM »
I have finally finished v1.0 of the archive for the NASA satellite tapes.

Sat-53123114313-Version1.0 (Object photos, text file.)

Sat-GFORKS-314N003-Version1.0 (Object photos, documentation, Akai RTR sample, visualized tracks)

Sat-GFORKS-314N079-Version1.0 (Object photos, documentation, Akai RTR sample)

Sat-GFORKS-330N100-Version1.0 (Object photos, documentation, Akai RTR sample)

Sat-SNTAGO-120J827-Version1.0 (Object photos, documentation, visualized tracks)

Sat-SNTAGO-314J019-Version1.0 (Object photos, documentation)

Sat-WINKFIELD-330P001-Version1.0 (Object photos)
« Last Edit: March 01, 2019, 07:23:14 AM by apollo16uvc »
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Offline apollo16uvc

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Playing back some ESA tapes
« Reply #34 on: March 08, 2019, 05:42:09 PM »
Some interesting new finds, did we play telemetry?

Last week I took the time to play some ESA tapes (1/2 inch 7-track) on my Akai X201D (1/4 inch 4-track)

The tapes played:
1.
SAT: ESRO 1A
TAPE ID: 680841-292-230
ESOC/Section TLM: 13496
DATE: 24 JULY 70

2.
SAT: 720,141
TAPE ID: 1135 05 10A
ESOC/Section TLM: 21554
DATE:

3.
SAT: TD-1
TAPE ID: 1117 09 08 B
ESOC/Section TLM: 16837
DATE: "Day 089"

4.
SAT: TD-1A
TAPE ID: 1118 07 09 A
ESOC/Section TLM: 16672
DATE:


To give you an idea of ​​how satellites sounded in the 60's and 70's check out this website with recordings.


I made a video where I play the tapes and show it on an oscilliscope:


Some remarkable details:
ESRO 1A has a lot of activity at the beginning, it looks like a reference signal that is being adjusted. There pitch changes and there are periods of noise. Eventually we receive a stable signal which is certainly more complex than a simple sine wave.

ESRO 1A:
Oscilliscope:


Spectrogram: seems to show a kind of square wave, would this be satellite data?


Signal played at 20% original speed, sounds like morse code.


The space between the signals is similar to track 6 of the ESRO 1A tape:


TD-1
Oscilliscope : The wave of this signal swells up and comes down again.



Spectrogram : And here you can see that too.


TD-1A
Oscilliscope:
This signal has two harmonic waves:


And when we zoom out, it has a kind of block pattern:


But when it is very interesting to delay the signal, it sounds like a morse code again.
Spectrogram:


Signal played at 15% original speed, sounds like morse code again.

A lot of new information that will take some time to process.

It seems to me quite possible that this is the received data. If we find documents from the relevant satellite with information about telemetry, should it be possible to create a program or circuit that processes the signal?
A program could convert it to a spreadsheet. How much volts the battery outputs every second for example.

I do not know anything about it, but the ESA recordings do not seem to be FM-modulated, since such a wave looks very different.
The NASA recordings are usually not, so apparently AM and FM modulation was not common in recordings from this time.
The NASA documentation usually also has "Direct" recordings and not "FM"

I am looking for people who may be able to help with the relevant satellites, and who are more acquainted with this kind of work.

Niels
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Offline apollo16uvc

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Re: Digitizing NASA data tapes
« Reply #35 on: March 16, 2019, 04:47:05 PM »
Gerald from the unmannedspaceflight forum has the following idea:


When coding the upper potential with 1, and the lower potential with 0, with a more or less fixed clock rate, we get pairs 01 or 10, never 00 or 11. So such a pair, or transition, seems to code a bit .
So it should be fairly easy to convert the signal into a bit stream.

Then it only requires us to find the relevant documentation so that we can write a computer program.

Voice found on beginning of NASA tape

On satellite tape 'Sat-SNTAGO-120J827' a voice can be heard briefly at the beginning. The voice probably tells us the recording time. "The time is 11 5 AM"

The satellite is Upsilon 61, the recording date was Sept 7, 1961

I had to play the recordings backwards.
Here the fragment as an MP3 file.
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Offline ka9q

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Re: Digitizing NASA data tapes
« Reply #36 on: March 16, 2019, 10:32:18 PM »
The 01 and 10 (never 00 or 11) sequences is call "Manchester coding", and it was a very popular line code at one time. It still is, though there are better alternatives now. It eliminates any DC component from the data and pushes the spectrum away from zero so it can be transformer or capacitor coupled or recorded on magnetic media using old-style electromagnetic-type heads. It's also self-clocking.

Offline apollo16uvc

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Re: Digitizing NASA data tapes
« Reply #37 on: March 17, 2019, 06:54:27 AM »
People told me pretty quickly what the recording was about.

The voice recorded was the WWV time signal, it was THE time standard in the US.

The tape document designates track 3 as "WWV Signal" I was already confused because none of the tracks were documented as a "Voice announce" track.

Between the two voice recordings, "1605" is sent in CW (morse code)
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Offline ka9q

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Re: Digitizing NASA data tapes
« Reply #38 on: March 18, 2019, 05:14:29 AM »
Between the two voice recordings, "1605" is sent in CW (morse code)
That's the Greenwich Mean Time (now UTC). In those days, WWV hadn't completely standardized on universal time; it transmitted local time in the voice announcements. Until 1966, it transmitted from Greenbelt Maryland (near NASA Goddard SFC), which of course was in the eastern time zone.