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Apollo Discussions => The Reality of Apollo => Topic started by: apollo16uvc on February 12, 2018, 03:20:59 PM

Title: Digitizing NASA data tapes
Post by: apollo16uvc on February 12, 2018, 03:20:59 PM
I am in contact with someone who will help me read NASA data tapes from the 60s to 70s

Some quick looks at the tapes showed Lunar Orbiter, Apollo, Skylab and sattelite 1/2 inch computer tapes.

They Will be uploaded to archive.org as public domain.

I will post findings and relevant parts of our conversation here.

Some tapes cost 80 dollar to acquire, if you want to help finance this you can email [email protected]

Regards,
Apollo16uvc
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 12, 2018, 03:21:23 PM
Me: "
Today I played part of the tape through an AKAI X201D. I did not expect to get any usable data, maybe a faint signal.

You can find WAV files and spectrograms here: https://drive.google.com/drive/folders/17vss0VXnpmGchf0DuRh3w2wXxNNphkYA?usp=sharing

Test001.wav through Test003.wav were manually moved along the heads. test004.wav and test006.wav was fed along the heads via the capstan at 3 3/4. test005.wav is played at 7 1/2 inches per second.

Test005.wav has a continuous tone.
test006.wav is the very beginning of the tape, and has weird bursts at the beginning."

Contact: "Having done a number of these for JPL, I'd say that this is a 7-track 800 BPI NRZI tape. Depending on the exact tape drive, it can probably be read on a 729-equipped 1401. Making sense of the data, however, is another story. Early 1960s NASA tapes tended to be 7090/94 ones, with later ones, Univac 1100 series right up through the early 1980s.

Or you can send it to me and I'll extract the data. My contacts at JPL say there are thousands of these things kicking around."

Me: "Thank you very much for your reply.

Can you any sense out of the sound recordings I have made? what are the short bursts on test006 and the tone on test005.


I would be incredible thankful if you could extract the data. How to best ship a tape? I have to send mine from the netherlands to your place, which I assume is America. Any further tapes I get I might have shipped directly to you from a seller in America. Whatever you want.

I know a lot of people will be excited to look at the recovered data.

Is it possible you can try and get the tape identified by the people at JPL? I did scrub off the upper label to reveal the lower label with some more information.."

Contact:"
No, I do not think that I could do anything with your audio. Perhaps an examination with a magnetic developer (such as Kyread) and a low power microscope would verify my suppositions. That would at least tell you how many tracks are involved and define the inter-block spacing, if applicable.

There's a faint possibility that these might also be analog telemetry tapes, but a view with a magnetic developer would verify that. However, what I can see of the partially-covered label seems to indicate a standard digital tape, but the note on the label that says "audio" is puzzling. Were that the case, you should be able to get something using an audio recorder to play these back.

I was under the impression that tapes used for analog telemetry back in the 60s was very different from standard 10.5" 1/2" tape, but you never know.

They're definitely digital tapes if you have blocks of data separated by approximately 3/4" of erased space. That's standard 7 track format.

Finally, a lot of these tapes are simple recertified "scratch tapes"--that is, used tapes returned to the scratch pool and run through a certifier (which erases all data). A tape label that specifies contents and the name of the programmer holds out the best hope, but even so, in the lots I've handled, about 10% were recertified scratch. NASA, like a lot of government operations, re-used tapes heavily, trimming off tape at the beginning when it wore out and applying a new BOT marker. Some of the tapes that I've worked on have several hundred feed sacrificed.

A lot of this stuff is mixed-format data (some text, a lot of binary) data that may be very difficult to suss out without the program that created it. For example, here's one of the tapes that I did: Mostly 7094 floating-point data with a few bits of 7090 BCDIC mixed in."

Me:"Really cool that you worked on NASA tapes before, how did that come to be? and how do the tapes usually end up in the 'wild'?

There are many unknowns, but with small steps I believe we can figure this out.

I looked around for Kyread, and buying from their website the shipping cost alone is 150 dollars. I can buy magnetic viewing film much cheaper, do you think it has enough resolution to view the tracks?

If it does have analog telemetry, is there a special type of audio recorder we need to play them on? or will any 7 track multi track recorder do? I do not know if a 1/2 inch 7 track audio recorder exist, 1/2 inch 8 track tape recorders were more common. Today I spooled the tape through my 1/4 inch 4 track stereo recorder again, this time there were 4 to 5 distinct frequency tones in the spectogram instead of one. Could it be overlapping tracks?

Is it possible rectifying a tape causes this continuous tone?

I may get some NASA tapes soon that have a greater potential to hold data."
*Pictures of tapes for sale*

Contact:"My tapes came directly from NASA JPL in Pasadena. I do not own them--and they were returned after data retrieval, along with the data retrieved from them. In other words, it's JPL's property, not mine and I treat it that way.

Kyread is nothing more than 1 to 3 micron iron particles in a fast-evaporating fluid (it used to be a type of Freon, but since that was banned, methyl perfluoroisobutyl ether is used). It is relatively inert, so it does not affect the coating or base material. You shake the bottle up and drop a drop of the suspension on the tape and allow the solution to evaporate. Since the iron particles are so small, you can visualize very small features in the tape. With a decent chemistry lab, it should not be difficult to mix some of this up in your location, assuming that the carrier liquid is legal in the EU.

When I have a new tape, unless I'm very certain about the content, this is always the first step. Tapes labeled as 9 track often turn out to be 7 track and vice-versa. What are you going to believe, your eyes or some lying label?

The other thing is preparation of the medium. Normally, the procedure is to "bake" the tape, then run it through a tape cleaning machine. Additional treatment may be necessary, such as lubrication, to get the tape to read. After all, you have no idea of the storage conditions during the 50 or so years that the tape has been in storage. It's not uncommon for splicing tape (used to attach leaders) to dry out and let go, so you have to be prepared for that. BOT and EOT markers similarly dry out and fall off...

The tapes you pictured above are certainly data tapes and definitely 7-track (9 track tapes don't usually occur with even parity). But you can't get your expectations too high. The Apollo program involved hundreds of subcontractors who generated probably tens of thousands of tapes. The GE tapes you show above may be nothing more than engine test data--and like such things, you need a Rosetta stone to interpret it, since it's unlikely that the data will contain any clues. Before the days of high-speed telecom and big disk drives, tape was king. Outfits like NASA ordered tapes by the truckload.

But, if you're willing to take a shot, I'm willing to have a go at it. I'll PM you my shipping address."

Our conversation continued in private and got quite technical.

I will try to get the tracks visualized on the tape currently with me and am looking into getting it played on a multitrack 1/2 recorder, if it is analog telemetry we might get something.

As for the data tapes, my contact will handle those.

Regards,
Apollo16uvc
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 12, 2018, 03:22:23 PM
"You can see an HP 7970 tape drive demonstrated at about 7:11 in this video:



Mine is a 7970B, modified to use a 7-track head instead of the standard 9 track one. The interface is "raw", which feeds into an STM32F407 microcontroller, which writes to a micro SD drive. While I could probably write 7 track tapes, mine is configured as read-only.

For 9 track tapes, I have several drives, but the one that I used most is a Fujitsu M2444 drive. It's impossible to see it working, as the door must be closed for it to operate. That is fed by a 16-bit ISA controller in a PC. The whole affair is rack-mounted."

The first tape has been send: https://www.ebay.com/itm/332544367534?ViewItem=&item=332544367534

As for the "Audio tape" I will be getting someone locally to play it with a multi track audio recorder. It is this tape: https://www.ebay.com/itm/Vintage-NASA-Audio-Data-Tape-Reel-From-The-1960-039-s-Who-Knows-What-May-Be-On-This-/332455504748
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 17, 2018, 02:40:00 PM
Tape: NASA Automatic Data Processing 4141 has arrived.

Update written by contact:

"Niels,
 
 The tape arrived today--the photos don't do it justice(?).    The reel is chipped and absolutely filthy--it looks as if it spent the past 50 years on the floor of someone's garden shed.
 
 At this point, it's difficult to tell how much of the tape is intact.   This is my plan:
 
 1.  Bake the tape for a day or two
 2.  Run it through the cleaning machine a couple of times to remove as much of the dirt as possible
 3.  Clean the reel and re-spool the tape
 4.  Try to see if there's anything readable
 
 How does this sound?"

"Well, I unreeled a bit of the tape; I didn't find a BOT marker, so I suspected that the first few meters of the tape are history
 
 Here's what I see when I look at the tape:
 
 9-track, not 7!  If the date on the tape is correct, this means it was produced on an IBM System/360, as almost nobody else had working 9 track drives then.    Even in 1965, IBM was shipping the first S/360s out with 729 7-track drives.   It took them awhile to get the bugs out of the 2400 series drives.
 
 Testing the very beginning of this very wrinkled tape shows data on the first few cm, so if there was a leader, it's been long gone.
 
 I'll bake and clean the tape and attach a BOT marker about 3 m in and see what I can see with my 9-track drives.  This may take a few days."
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 18, 2018, 07:36:10 AM
The tracks on the tape visualized with a magnetic viewing solution:

(https://i.imgur.com/9IToU7E.jpg)
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 25, 2018, 06:13:08 AM
A even greater magnification closeup of the tracks:
(https://i.imgur.com/ihPptbk.jpg)
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on March 03, 2018, 07:30:42 PM
The NASA ADP tape may not be readable with conventional computer tape drives, as the ADP contains telemetry and not data. We may figure out a way to digitize it eventually.

We have had a succes with two other tapes though! Switch-Action TP 1820 and 2909 have been read and successfully converted to .tap and ASCII text. I have had a look and think it is absolutely fascinating.

When I have the time and some more info I will make a public archive and put the files there.

Cant wait to share this with you!

Regards,
Niels
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on March 04, 2018, 05:30:22 AM
The tapes with their files can be found here:

https://archive.org/details/SpaceData

(https://ia601500.us.archive.org/3/items/SpaceData/SwitchActionTp1820Photo-1.png)

All thanks go to Chuck for reading the 7-track tapes for me. This would not have been possible without his help. More tape recovery may come from him later so stay tuned.
Title: Re: Digitizing NASA data tapes
Post by: ajv on March 04, 2018, 01:43:58 PM
12 12 L DI 0276  SIC LOX BUBBLING DUCTS 1 + 3  M DO 0276 ON

Cool!
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on March 17, 2018, 01:29:59 PM
Two more tapes have arrived this week, a quick update below:

"The second set of tapes arrived in good form. At first blush, they seem to be more switch panel data, but we'll know more later.

Unlike the last batch that were equipped with poly "tape hanger" strips, these were in 60s-era 3M hard styrene cases. That was good news and bad news. The good news is that the cases use a weatherstrip-type rubber foam to seal the edges of the two case halves. The bad news is that the foam has gone the way of all old rubber and deteriorated, essentially gluing the case halves together. With some coaxing and hard pulling, however, they came apart. I removed the bad foam so that this won't be a problem in the future.

I baked and cleaned the tapes (1179 was a bit sticky) and did a quick run-through of them.

2090 reads perfectly; no issues--the data looks much like the previous tapes; 132-character records of what I'm supposing are switch legends. Only one single parity error (I can isolate it to a single byte). 14,404 records amounting to about 2 MB.

1179 starts off the same way, but after about 663 blocks, everything goes to hell. Parity errors, short blocks, incomplete records. The only way I can think of resurrecting anything is to simply read without retrying all the data I can, and then trying to make some sense of the result. My suspicion is that the tape was stored (for years) close to a magnetic field and so became partially erased. Physically, the tape is in fine condition; not shedding or displaying any other physical damage."
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on March 18, 2018, 04:20:50 PM
Uploaded 2090
(https://ia801500.us.archive.org/3/items/SpaceData/SwitchActionTP2090Photo-Front.JPG)
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on March 20, 2018, 12:32:25 PM
We are currently brainstorming on the best way to digitize 1179. When processing the BCDIC data to ASCII we get mostly garbage and the occasional readable string.

The best way might be to read it without any retries and try and make something out of it, this may requirements a firmware hack of the drive. The .TAP format does support forward and backwards retries but it reads the same errors each time.

(https://www.dropbox.com/s/6a3718t7kxlfbmu/Switch%20Action%20TP%201179.JPG?dl=1)
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on July 08, 2018, 07:38:18 AM
Working on four other tapes.

I'm starting here with the tape QK7992H from NASA in the lot of 4. I suspect that it's the best as it's probably the original.

(https://www.astroforum.nl/filedata/fetch?id=1384978&d=1531000484)

The SIMH file can be downloaded here: https://archive.org/download/SpaceData/QK7992H.zip

At any rate, count this as a test only--there appears to be only one uncorrected parity error in block 130.

Note that any text in these is EBCDIC, not ASCII. The data structure appears to be fixed length records of 83 (total) bytes, each record starting off with its number in EBCDIC. Initial records are entirely in text; subsequent records are binary data.

For example, the first physical block (translated from EBCDIC to ASCII) is:

Code: [Select]

20 20 20 20 |..Block 0:.. |
00000010 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000020 20 20 20 20 30 30 30 31 30 30 30 31 30 37 36 38 | 000100010768|
00000030 30 37 36 38 20 20 20 31 20 32 20 32 30 32 30 20 |0768 1 2 2020 |
00000040 31 35 33 30 20 20 20 20 20 20 20 20 20 20 20 20 |1530 |
00000050 31 20 20 43 20 20 20 20 20 20 2a 20 20 20 20 20 |1 C * |
00000060 20 2a 20 20 20 20 20 20 2a 20 20 20 2a 20 20 20 | * * * |
00000070 2a 20 20 20 37 32 30 2a 20 20 20 20 20 20 2a 20 |* 720* * |
00000080 20 20 2a 20 20 2a 20 2a 20 2a 20 2a 20 2a 20 2a | * * * * * * *|
00000090 20 20 20 20 20 2a 20 20 32 20 20 43 4c 57 52 31 | * 2 CLWR1|
000000a0 35 33 30 20 20 20 56 45 53 54 41 2c 31 32 4d 49 |530 VESTA,12MI|
000000b0 4e 2c 53 4d 2e 41 50 2e 2c 4c 4f 2d 44 49 53 50 |N,SM.AP.,LO-DISP|
000000c0 20 20 5a 45 4c 4c 4e 45 52 2f 4d 41 59 20 32 31 | ZELLNER/MAY 21|
000000d0 2c 31 39 37 38 20 20 20 20 20 20 20 20 20 20 20 |,1978 |
000000e0 33 20 20 43 43 41 4d 20 32 20 49 4d 41 47 45 20 |3 CCAM 2 IMAGE |
000000f0 31 35 33 30 20 20 20 20 20 20 20 20 50 52 4f 43 |1530 PROC|
00000100 20 56 45 52 53 4e 20 32 31 31 20 50 41 52 41 4d | VERSN 211 PARAM|
00000110 20 53 45 54 20 4e 4f 20 38 20 20 20 20 20 20 20 | SET NO 8 |
00000120 20 20 20 20 20 20 20 20 34 20 20 43 20 20 20 20 | 4 C |
00000130 20 20 20 4e 4f 20 4c 41 4d 50 2d 45 58 50 20 54 | NO LAMP-EXP T|
00000140 49 4d 45 3d 37 31 39 20 53 45 43 53 20 20 20 20 |IME=719 SECS |
00000150 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
*
00000170 35 20 20 43 |5 C

I think you should read the text like this:

530 Vesta, 12 MIN, SM.AP., LO-DISP

ZELLNER / MAY 21 1978 3

CCAM 2 IMAGE 1530 PROC VERSN 211

PARAM SET NO 8 4 C

NO LAMP-EXP TIME = 719 SECS


The "ZELLNER" and "VESTA" surprised me, as neither Pioneer 10 nor Pioneer 11 did any imaging in the asteroid belt (Vesta is a big asteriod).

A little Googling makes this clear:
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780021064.pdf

"Dr. Benjamin H. Zellner
Lunar and Planetary Laboratory University of Arizona
Tucson, Arizona 85721 "

"B. ZELLNER. Geography of the Asteroid Belt ..................... 99"

Benjamin H. Zellner is an astronomer who was in the UofArizona at that time. His specialty was asteroids. As far as I know he still lives - hopefully he can tell us what's on the tape?

In the document he talks about UBV, in my opinion color or intensity data of asteriodes observed with an observatory. This explains the exp time of 719 seconds. Can CCAM stand for a CCD sensor?

How is that for an imitation of Sherlock Holmes? Give me a role rusty mylar and I find the owner.
Title: Re: Digitizing NASA data tapes
Post by: ka9q on July 09, 2018, 01:06:34 AM
Keep up the good work!!
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on August 04, 2018, 12:25:46 PM
The last Switch Action tape that was having tons of reading problems has been digitized!

"I had another go at 1179 (new code, re-calibratomg read ampliffiers).
Much better results this time, though not absolutely perfect, but pretty
remarkable for a 46 year old tape"

Switch Action Tape 1179, rocket identification SA-511, Apollo 16

 
(https://archive.org/download/SpaceData/SwitchActionTp1179photo-front.JPG)

(https://archive.org/download/SpaceData/SwitchActionTp1179photo-rear.JPG)

De band in de drive:
(https://archive.org/download/SpaceData/SwitchActionTp1179Mounted.JPG)

Info, SIMH bestand en ASCII omzetting: https://archive.org/download/SpaceData/SwitchActionTp1179.rar

The data is comparable with other Switch Action tapes, with some interesting things like it mentioning tthe UI and other specific parts of the rocket. Here is a sample:

Code: [Select]

R/L 40M17360-11   E/O 8S-0411    REV K    D/I 10/11/71   ECP 10-3218   E                                                           

Block 10:

R/L 40M17360-11   E/O 8S-0412    REV L    D/I 10/27/71   ECP 10-3216   E                                                           

Block 12:

R/L 40M17360-11   E/O 8S-0413    REV M    D/I 10/28/71   ECP 10-3206   E   511 FRT-1                                               

Tape mark at 13

S     02 02 L DI 0026  EDV SII INT HY STBY HY CHG C  M DO 0026 ON  C A                                                             

Block 53:

S     02 03 L DI 0027  EDV SII INT HY STBY HY CHG O  M DO 0027 ON  C A                                                             

Block 54:

S     02 04 L DI 0028  EDV IVB AFT SLINE WD SYCHG C  M DO 0028 ON  C A                                                             

Block 56:

S     02 05 L DI 0029  EDV IVB AFT SLINE WD SYCHG O  M DO 0029 ON  C A                                                             

Block 57:

S     02 06 L DI 0030  EDV IVB AFT HY WD GN SYCHG O  M DO 0030 ON  C A           

Block 674:

S     19 21 L DI 0453  INT AUDIO SELECT POS NO. 1    M DO 0453 ON  C B                                                             

Block 676:

S     19 22 L DI 0454  INT AUDIO SELECT POS NO. 2    M DO 0454 ON  C B                                                             

Block 677:

S     19 23 L DI 0455  INT AUDIO SELECT POS NO. 3    M DO 0455 ON  C B                                                             

Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on August 06, 2018, 05:49:42 AM
Replaced .rar with .zip to comply with standard:
https://archive.org/download/SpaceData/SwitchActionTP1179.zip
Title: Re: Digitizing NASA data tapes
Post by: molesworth on August 06, 2018, 04:32:26 PM
Fascinating stuff!  I admire your persistence in digging through all of these - a real labour of love, so to speak  :)

It's real industrial archaeology, and with the 50th anniversary coming up next year, of real significance.
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on August 29, 2018, 03:43:32 PM
greetings! I got great news: We have processed the first image from one of my Pioneer tapes.

All thanks go to Leo for processing the first image on Pione-QK7992H tape. Thanks a lot for your work Leo!

Some info:
The image data should contain two colour channels, blue and red, but for now we have just processed everything as grayscale. We are not sure yet how to process the colour channels. The image data is 6-bit with 64 intensity values. It has been processed into a PNG.

RAW image:
(https://i.imgur.com/wD3eE5i.png)

Contrast equalized:
(https://i.imgur.com/KvJZ30O.png)

https://imgur.com/a/i6l8RUO

Update: A GIF with three images recovered so far:
(https://i.imgur.com/TlVAQNL.gif)
Title: Re: Digitizing NASA data tapes
Post by: nickrulercreator on August 29, 2018, 04:32:34 PM
How much are the tapes you're buying on eBay?
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on August 30, 2018, 01:57:53 PM
How much are the tapes you're buying on eBay?


between 25 and 80 dollars a piece.
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on September 16, 2018, 02:37:08 PM
Hans and Daschmid have been doing some great work on deciphering the Switch Action tapes. Here is some information we found recently.

Here are some more educated guesses about the format:

Example of header:
R/L 40M67790-6 E/O 2T-0038 REV AS D/I 11/10/72 ECP 10-3205 E

  - The headers at the top of each file imply this is controlled
  engineering data.  The strings starting with '40M' look like NASA
  part numbers, and the E/O (Engineering Order), REV (Revision) and
  ECP (Engineering Change Proposal) fields are familiar from other
  NASA documents.

Example of other lines:
S 04 11 M DI 0083 SIB THRUST FAILURE IND L DO 0083 ON C H

  - Columns 7-12: incrementing ID?

  - Columns 13-22: appear to describe the primary hardware operation
    associated with the measurement.  There are a few different
    formats, but I think:

            {L,M} DI #### = Get Digital Input ####
            {L,M} DO #### = Set Digital Ouput ####
            D EE #### = Discrete Event Evaluator ####

The 'L'- and' M'-tags stand for the  'Launch Control Computer Complex' and 'Mobile Launcher'.

  - The three character field starting at column 24 is the systems
    area/responsible position for the measurement/command:

            SIC  - Saturn V 1st Stage
            SIB  - Saturn IB
            SII  - Saturn V 2nd Stage
            IVB  - Saturn V 3rd Stage
            IU   - Saturn Instrumentation Unit
            INT  - Integration
            EDS  - Emergency Detection System
            LSE  - Launch Support Equipment
            NAV  - Navigation
            PL   - Propellant Loading
            PWR  - Power
            OAT  - Overall Acceptance Test?
            EDV  - ?

  - Colums 28-52: Measurement Nomenclature

  - Colums 54-67: (sometimes) hardware operation to execute command
            e.g, if "SIC TERM COUNTDOWN SEQ RESET  L DO 0131 ON"
            writing "ON" to Digital Output #131 would execute
            "TERM COUNTDOWN SEQ RESET"

I think this is a reasonable guess at the formatting.

Lets look at some tapes from Apollo 16 and Skylab 2:

Looking at the headers from each:

Tape 2909, Block 3:
R/L 40M17360-11   E/O 8S-0405    REV D    D/I 06/15/71   ECP 10-3148   E   511 BASELINE

Tape 1179, Block 12:
R/L 40M17360-11   E/O 8S-0413    REV M    D/I 10/28/71   ECP 10-3206   E   511 FRT-1

'511' is AS-511, the launch vehicle for Apollo 16.  'FRT' is 'Flight Readiness Test'.

Detailed info on AS-511: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730025090.pdf

There's a table of prelaunch milestones on page 3-2 (46).  AS-511 had its Flight Readiness Test on 3/7/1972 and was launched 4/16/1972.  Considering the long lead times for checkout and configuring hardware (AS-511's S-IVB arrived at the Cape in July 1970), the dates on the tape seem reasonable.  Note also that Tape 2909 has headers for revisions 'A'-'D' and 1179 has revisions 'E'-'M'

Tape 2090, Block 0:
R/L 40M67790-6    E/O 2T-000000  REV      D/I            ECP 10-
                     Block 2 ends with:
40M67790-6  206 BASELINE

Tape 1820, Block 54:

R/L 40M67790-6    E/O 2T-0038    REV AS   D/I 11/10/72   ECP 10-3205   E
                     Block 56 ends with:
40M67790-6  206 BASELINE

Here '206' is SA-206, the launch vehicle for Skylab 2.

SA-206 flight manual: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740021163.pdf
SA-206 postlaunch evaluation: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730025087.pdf

Again the dates line up(With our tapes)

In the SA-206 postlaunch evaluation there's some discussion of an anomaly at launch, where the ground Digital Events Evaluator (DEE-6), recorded a momentary "thrust failure indication and cutoff start indication".  These two discretes are present on the tape, although unfortunately the evaluation doesn't say which discretes they were:

D           D EE 0083  SIB THRUST FAILURE IND
D           D EE 0085  SIB CUTOFF START IND


I doubt now that this file was associated with the LVOS.  Based on IBM's paper describing the system, it appears that it was first used on ASTP and wouldn't have been in use at the time the tapes were created:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750051202.pdf
 
Very detailed information about the RCA-110A's and their interfacing equipment: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690001882.pdf

The 'L' and 'M' tags in the file are 'Launch Control Computer Complex' and 'Mobile Launcher'.  So:

S     04 11 M DI 0083  SIB THRUST FAILURE IND        L DO 0083 ON  C H

Defines Switch Action #0411:
   Mobile Launcher Digital Input #0083
       name=SIB THRUST FAILURE IND
       on receipt: SET LCC Digital Output #0083 to ON

There's a matching entry for L DO 0083:

S     04 11 L DO 0083  SIB THRUST FAILURE IND             NONE     C H

Which would correspond to a light or other indicator on a Firing Room Console.

There's also a DEE entry, which I'm guessing tells the Digital Event Evaluator to log changes associated with that Digital Out:

D           D EE 0083  SIB THRUST FAILURE IND                     


Check out these two extremely detailed docs:

Saturn Launch Computer Complex Programmer's Manual: http://www.ibiblio.org/apollo/Documents/SLCC_Programmers_Reference_Manual.pdf

AS-503 Verification Test Programs, 73V1201: http://www.ibiblio.org/apollo/Documents/AS-503VerificationProcedures.pdf

You won't find a definition of the the actual Switch Action Table tape format, but the tape is clearly describing the configuration information for the SLCC system.

On page 3-9/3-10 (56 in the PDF) of the programmer's manual, it mentions the "Discrete Executive":
"The Discrete Executive initiates logging at both computers. There are a number of different types of discrete tables each containing specific data. These tables are:
   * LDO and MDO Profile table
   * LCCC and MLC Discrete Status tables for IODC's 5 and 7
   * General Discrete Log table (LDI, LDO, and MDI Changes)
   * MDO Issue table"

Section 4.1.1 on 4-3 (p.66) describes "Launch Vehicle Input/Output, Discrete Input/Output" and give details on LDI/LDO's and MDI's/MDO's, which as suspected are LCCC/MLP Digital Input/Outputs.

73V1201 contains the test procedures for verifying the LCC computer software and interface to the launch vehicle are operating correctly.  There's a lot of interesting details here, but first check out "Discrete Initialization and Modification (NT98/NT99)" (p.24).  Section 5.2.2 (p.27) says:
"5.2.2 Place cards in the card reader to perform the following action table modification:
     MDI 0010 0N - LDO 1200 issued ON
     MDI 1200 0N - LDO 0010 issued 0N
     LDI 0033 0N - MDO 0619 issued 0N
     LDI 0619 0N - MDO 0033 issued ON"

That sounds an awful lot like our tapes.  My guess is they're the input data for the NT98 Discrete Initialization Program, which unfortunately isn't described in detail.  If anyone can locate the following documents, I bet we'd find what we need there:

Specification for the Operating System for the Saturn V Launch Computer Complex, Volume 1, Revision 1.
MSFC No. III-4-440-4

Operator Reference Manual for SLCC Progranrning System,
MSFC No. lII-4-440-5, IBM No. 68-F11-0003, dated 15 June 1968.

User Instructions for Saturn V Launch Computer Complex Operating System and Test Programs
MSFC No. III-4-462-1


There are numerous references to specific LDI/LDO/MDI/MDO numbers in the test procedures and while all of them don't match up with the data in the file, many do.  On page 39 while testing the $DMON display monitor program, LDI0346 and MDI0459 are associated with the "ground camera arm switch" on the vehicle camera networks panel.  Sure enough:

S     15 10 L DI 0346  INT GND CAMERAS ARM COMD      M DO 0346 ON  C B
S     15 10 M DO 0346  INT GND CAMERAS ARM COMD           NONE     C B
S     20 03 M DI 0459  INT GND CAMERA ARMED          L DO 0459 ON  C B


Another interesting example is the Launch Vehicle Data Adapter communication interfaces.  See the "LVDA STATUS CODE CONVERSION CHART" on p.146.   The LVDA sends back binary words on MDI0733-MDI0738:

S     31 13 M DI 0733  IU  MODE CODE 1 IND           L DO 0733 ON  C G
S     31 14 M DI 0734  IU  MODE CODE 2 IND           L DO 0734 ON  C G
S     31 15 M DI 0735  IU  MODE CODE 3 IND           L DO 0735 ON  C G
S     31 16 M DI 0736  IU  MODE CODE 4 IND           L DO 0736 ON  C G
S     31 17 M DI 0737  IU  MODE CODE 5 IND           L DO 0737 ON  C G
S     31 18 M DI 0738  IU  MODE CODE 6 IND           L DO 0738 ON  C G


For example, if MDI0736 and MDI0734 are ON that indicates "PREPARE TO LAUNCH WITH A PLATFORM"

My current thinking is that the tapes are describing the discrete I/O configuration of the two RCA-110A computers used to interface between the Launch Control Center and the Mobile Launcher.  Switches and indicators on consoles in the Firing Room were wired into an RCA-110A computer (The "Saturn Launch Control Computer Complex"), and from there commands could be sent across a serial link to another RCA-110A in the Mobile Launcher.  The Mobile Launcher computer communicated with relay racks and other equipment on the pad and LV, including the Saturn LVDC.
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on September 16, 2018, 02:48:55 PM
Three different processings of duo-colour images from one of the three (RED)-(BLUE) channel images:

(https://i.imgur.com/4RkLpSe.png)
(https://i.imgur.com/lUiZEu7.png)
(https://i.imgur.com/JytCKmg.png)
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on December 29, 2018, 07:15:03 PM
Since last week I have bought 4 NASA tapes from Ebay. It is 1/2 inch tape on a 10.5 inch reel and has 7 tracks. The tapes are recorded with Ampex FR-100 and Ampex FR-600 instrumental recorders. On the tapes are analog telemetry signals from satellites, recorded at NASA stations in 1963.

(https://www.retroforum.nl/uploads/monthly_2018_12/1-1.thumb.jpg.70391b625cc41d3e4fdd398770fbd760.jpg)
(https://www.retroforum.nl/uploads/monthly_2018_12/1-2.jpg.8c4ee71afbbcecc49886cd73653ae65e.jpg)
(https://www.retroforum.nl/uploads/monthly_2018_12/1-3.thumb.jpg.af3057a407c9147965267cb517838bcc.jpg)

It seems that there are 6 telemetry tracks, and 1 voice track.

I do not have have Ampex FR-100 or FR-600, and they are very scarce. Nor do I have a 1/2 inch 8-track recorder.

What now? There are 8-track 1/2 sound recorders. The height difference between 8 and 7-track is so small, I think you can play a 7-track tape on an 8-track recorder.

If you adjust the 8-track head up and down, to align it with 1 track at a time I think we can pick up a good signal. I have talked with someone, and he says the tracks are just analog waveforms. I once played a 9-track 1/2 tape on a 1/4 4-track recorder, and I received an unusable but stable signal.

It would be best to use an Ampex FR-100 and FR-600, but I think it's unlikely that we will encounter them.

Hopefully the satellite tapes will arrive in the next two weeks, then I will be able to judge their condition, and if they need to be baked or not. But because the SSS might be in the middle or end, and not at the start, its going to be difficult as I can't unspool all of the tape.

I am talking with somebody in the Netherlands who has several 8-track 1/2 machines, but has not used them for years and doesn't know if they work correctly or not. If none work, one may have to be repaired. I'll then loan the machine for my tapes. I will also work out if I can buy the repaired recorder or not, that would be great for future projects!

If I setup a crowdfund for the repair would anybody be willing to help fund it?

Currently I am digitizing two 1/4 inch home recordings of Mercury and Gemini news coverage, including John Glen's flight! will be up soon. My Akai X-201D and Revox A77 MK 4 need repairs too but thats an other matter. The Akai X-201D gets a noisy channel after a while (Especially when you turn it off and on) and the Revox A77 has mechanical and relay problems.

Will keep you guys updated!

Happy Holidays,
Niels
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on December 30, 2018, 08:12:41 AM
Is there anybody who can try and identify the satellites? this are the sat identifications on the documentation and tapes:

1963 30B

1963 14B & 14C

?? 63 14A & B

6330213
(or)
63302|3

In order to celebrate (almost) New year, I have decided to release an unfinished version of the processed data from Pione-QK7992H done by Hans.

there are 12 files on the tape, of which we have confirmed 6 to be image files, and have decoded them. There are 3 B/W images and 3 duo-colour images. (file1, 2, 6, 7, 11, 12)

As to what is on them... we do not yet know. If you know anybody that could help, tell him about me!

As for the 6 remaining files, we are not sure what those are. Their ASCII metadata is similar to the image files, but the data is different. By processing some of the remaining files anyway, we get weird patterns that could hint to some kind of image format, but we don't know!

Hans has separated the binary data from all 12 files from the SIMH file and put each in their own folder. When applicable he converted them to images. Each folder is supplied with the raw binary data and readable ASCII metadata.

Note this is unfinished, as some non-image files have only their metadata supplied, not the binary data. This will be done later when Hans has the time.

https://archive.org/download/SpaceData/Pione-QK7992H-Processed-Alpha.zip (https://archive.org/download/SpaceData/Pione-QK7992H-Processed-Alpha.zip)
(File scanned by VirusTotal, no positives: https://www.virustotal.com/#/url/65fdc7a34fb300a82fb02bcaaebdcaf06befbcb89a9013625ef191a69ccc3c63/detection (https://www.virustotal.com/#/url/65fdc7a34fb300a82fb02bcaaebdcaf06befbcb89a9013625ef191a69ccc3c63/detection))

For more discoveries in 2019!
Niels
Title: An update on the satellite telemetry tapes #2
Post by: apollo16uvc on January 03, 2019, 04:14:26 PM
Hello everyone,

Two of the four satellite tapes have arrived, the other two are coming later.

I have good and bad news; first we look at the good:

As you can see in the photos, the reels and tape are in good condition. All reels were carefully packed with original documentation in an aluminum holder. This holder was in two layers of cardboard. The cardboard seems to have a bit of water damage, but the tape has remained protected in the holder, which also has no rust. The reel has no scratches and dents.

The tape does not smell and looks good. I do not notice any mold or rotting. Optically, the tape is clean with little scratching on the playback side.

I have unspooled part of the tape and I do not notice any Sticky Shed Syndrome, although of course I could only check the beginning.

Now then, I dared to attempt to play the tape on my Akai X201D 1/4 4-track tape recorder. I did this by unwinding a piece of the tape and guiding the tape through the tape path guides and capstan. The tape gets pulled through the capstan in another box. With clean gloves, I make sure that the tape runs over the heads at the right pressure.

This was a success in itself because I received a number of signals. By carefully moving the tape up and down, I can try to focus on 1 track. Further than this I did not come.

I am talking to p.lankhaar about borrowing an 8-track tape recorder. He is testing his recorders to see if they are still working properly. Hopefully we can play the tapes better with one of those.

The bottom sound file are the interesting pieces from a few minutes of play on 7-1/2 I.P.S

https://www.dropbox.com/s/k2jbyoka6n50yhh/314N003-10786168-2.flac?dl=0 (https://www.dropbox.com/s/k2jbyoka6n50yhh/314N003-10786168-2.flac?dl=0)

The tapenumber on the boxes and documentation is 3141/2N003
The number on the reel itself is 10786-16-8
Satellite: 1963-014A & B (ERS5)
Recorder: FR-100
Speed: 15 I.P.S
Station Name: GFORKS


With this we have proven that something is on the tape, and it can be picked up with a sound head.

And now the bad news: Tape 10678-159-29 / 330p001 I also tried to play, and I get no signal, just as if there was no tape at all. Maybe this tape has been erased, or recorded with another recorder that does not play on my Akai. Anyway, I do not have a sample of it at this moment.

There are two other tapes on their way, I will give an update as soon as I have tried to play those.

Regards,
Niels
Title: Update #3
Post by: apollo16uvc on January 13, 2019, 05:20:04 PM
Update #3


The other two tapes have arrived. One with audio like the last one, second one without audio. Again I suspect i'm just not able to unspool it far enough. Luckly again no evidence of SSS and tapes are in excellent condition. A fifth tape is on the way and I am looking into buying a sixth one that might have audio from the Vanguard satellite.

I've been talking with a dutch reel to reel recorder enthusiast, and he has several 8-track 1/2 inch recorders. He has Teac 80-8, Tascam 38 and Otari units. Unfortunately, he is very busy with work and doesn't have much free time.

His Otari MX-5050 8 unit is most interesting to me since it can play two speeds, 7/1-2 and 15 I.P.S which is what I need.

After taking a look, all mechanical functions appear to be working. Playback, fastforward/rewind. When he sends a sound from the build-in tone generator to the recording input, all VU meters register correctly and there is sound.

But...there is no sound on playback! its possible there is nothing on the tape, he will try and find an other one to test once he has the time.

Neither of us have the parts, equipment and time to repair and calibrate such a machine. So its likely we have to hand it over to a company for repairs and calibration.

All the best.
Title: Re: Digitizing NASA data tapes
Post by: Obviousman on January 13, 2019, 07:50:45 PM
Great work. If you set up a crowd-funding account, I'll certainly contribute a little to help things out.
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on January 29, 2019, 11:09:34 AM
Update #4

I've got good, and great news.

First the good news, I assembled a small setup to be able to play more of the tapes on my 1/4 inch 4-track recorder. I played the tapes that I previously was afraid had no signals at all, and after some time (8-10 minutes) they too give the expected signals. So far I got 6 tapes, 5 of which hold signals.


The great news i've got, is that I have recorded the reference track briefly by moving the tape up and down. The reference is a 10Khz tone on track 4, as seen on the attached document. Skip to (2:35) on the attached .mp3 file. Its exactly 10Khz on the recording.

314N079 Sample 2 mp3 (https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=46255.0;attach=1541683;sess=54302)

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=46255.0;attach=1541684;sess=54302)
314N079 documents

Later on when I will make proper scans of all documentation and cases.

It would be useful if we knew the track geometry of the FR-100, FR-600 and Otari MX-5050 8. We should be able to actually see this on the tape by using a magnetic developer solution. They are very expensive to buy and ship, so I have talked with Chuck on how to make it myself. It is quite simple, and he tried it on a floppy disk with good results and no damage to the data. With detailed macro photos we can figure out how well the tracks align.

Stay tuned!
Niels
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 02, 2019, 06:42:52 PM
I scored a dual channel 50Mhz Tektronix scope from school. They got digital scopes now and have been giving away their old analog ones to students.

That is going to be really cool for video's.
Title: Re: Digitizing NASA data tapes
Post by: nickrulercreator on February 09, 2019, 06:15:03 AM
Where on eBay do you find these? Like what to search?
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on February 11, 2019, 10:46:45 AM
Where on eBay do you find these? Like what to search?
Usually at the recording media or NASA sections, like so: https://www.ebay.com/itm/RARE-Official-NASA-1961-Scientific-Data-Recording-Speech-Folding-Experiments/183679829736
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc 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 (https://youtu.be/I85-aZuupxM)
(https://forum.nasaspaceflight.com/assets/46255.0/1544287.jpg)
(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=46255.0;attach=1544291;image)
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc 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.
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc 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 (https://archive.org/download/SpaceData/Sat-53123114313-Version1.0.zip) (Object photos, text file.)

Sat-GFORKS-314N003-Version1.0 (https://archive.org/download/SpaceData/Sat-GFORKS-314N003-Version1.0.zip) (Object photos, documentation, Akai RTR sample, visualized tracks)

Sat-GFORKS-314N079-Version1.0 (https://archive.org/download/SpaceData/Sat-GFORKS-314N079-Version1.0.zip) (Object photos, documentation, Akai RTR sample)

Sat-GFORKS-330N100-Version1.0 (https://archive.org/download/SpaceData/Sat-GFORKS-330N100-Version1.0.zip) (Object photos, documentation, Akai RTR sample)

Sat-SNTAGO-120J827-Version1.0 (https://archive.org/download/SpaceData/Sat-SNTAGO-120J827-Version1.0.zip) (Object photos, documentation, visualized tracks)

Sat-SNTAGO-314J019-Version1.0 (https://archive.org/download/SpaceData/Sat-SNTAGO-314J019-Version1.0.zip) (Object photos, documentation)

Sat-WINKFIELD-330P001-Version1.0 (https://archive.org/download/SpaceData/Sat-WINKFIELD-330P001-Version1.0.zip) (Object photos)
Title: Playing back some ESA tapes
Post by: apollo16uvc 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. (http://'http://www.dd1us.de/historical%20sounds%20from%20space.html')


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:
(https://archive.org/download/apollo16uvc_gmail_TD12/ESRO-1A.png)

Spectrogram: seems to show a kind of square wave, would this be satellite data?
(https://archive.org/download/apollo16uvc_gmail_TD12/ESRO-1A-3.png)

Signal played at 20% original speed, sounds like morse code.
 (http://'https://archive.org/download/apollo16uvc_gmail_TD12/TD-1A-3.mp3')

The space between the signals is similar to track 6 of the ESRO 1A tape:
(https://archive.org/download/apollo16uvc_gmail_TD12/ESRO%201A-17.JPG)

TD-1
Oscilliscope : The wave of this signal swells up and comes down again.
(https://archive.org/download/apollo16uvc_gmail_TD12/TD-1-2.gif)
(https://archive.org/download/apollo16uvc_gmail_TD12/TD-1.png)

Spectrogram : And here you can see that too.
(https://archive.org/download/apollo16uvc_gmail_TD12/TD-1-Spectrogram-1.png)

TD-1A
Oscilliscope:
This signal has two harmonic waves:
(https://archive.org/download/apollo16uvc_gmail_TD12/TD-1A-1.png)

And when we zoom out, it has a kind of block pattern:
(https://archive.org/download/apollo16uvc_gmail_TD12/TD-1A-2.png)

But when it is very interesting to delay the signal, it sounds like a morse code again.
Spectrogram:
(https://archive.org/download/apollo16uvc_gmail_TD12/TD-1A-Spectrogram-1.png)

Signal played at 15% original speed, sounds like morse code again. (http://'https://archive.org/download/apollo16uvc_gmail_TD12/TD-1A-3.mp3')

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
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc on March 16, 2019, 04:47:05 PM
Gerald from the unmannedspaceflight forum has the following idea:
(https://archive.org/download/apollo16uvc_gmail_TD12/index.png)

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. (https://archive.org/download/apollo16uvc_gmail_TD12/Sat-SNTAGO-120J827-sample-1.mp3)
Title: Re: Digitizing NASA data tapes
Post by: ka9q 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.
Title: Re: Digitizing NASA data tapes
Post by: apollo16uvc 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)
Title: Re: Digitizing NASA data tapes
Post by: ka9q 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.