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