Magnetic belt format

It might be this...

Possibly an IBM dictation machine belt:

These guys sound like they're in the business of transcribbling old tapes. They might be more helpful than my guessing.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Similar - but there are some significant differences. The mystery belt has only a single hole in the edge and there appears to be a splice in it (which suggests to me that it was made up from readily-available tape stock by a firm who could not afford to have a special loop format made just for their system).

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~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Hmmmm, nothing like it in the history of recording media I'm familiar with and that covers a broad area. I don't see a need to record anything on that but for maybe voice on a portable device. Given its size and endless loop configuration I can envision an audio head traveling across the width while its running. But recording to reels of tape or wire has been around for 75 years or so.

Could be out of some scientific data recording device that would be left outdoors in a location to record meteorological/geological data.

I don't recognize what it is but I do recognize what it isn't if that makes sense.

I would say you're closer than 'in the ballpark'.

Sorry, I can't help much. Seems that there would be a dropout as the splice went past the head. If it's for data recording, then the index hole would most likely make the recording wait until the splice had gone past the head.

You might well want to see the tracks on the belt. The popular green magnetic viewing film is much too insensitive and has poor resolution compared to other devices and methods.

Of course, once you see the tracks, then you need to figure out what to do with them! That's when the real fun begins.

There used to be (late 1960s, early to maybe mid 1970s) preparations of fine gray magnetic powder in a volatile carrier liquid. You'd shake the container to undo settling, pour some into a little "dish", and dunk audio tape into the liquid. It took a bit of technique, but you'd see the recorded pattern. You'd surely want to clean off the tape afterwards!

Beware of such a preparation that contained iron carbonyl; that's poisonous. Almost certain that what I used was not toxic.

3m made a curious magnetic viewer of that variety, which was re-usable. It had a suspension of fine brown particles in a closed container.

Eventually, Arnold Magnetics took over the distribution and maybe manufacture.

Both the consumable-suspension and Arnold viewer have quite-good resolution and sensitivity.

I must stress that if this is like the one I once owned, it's critically important to treat the bond between the Al foil on the bottom and the plastic body with uncommon care. It's not fragile, but don't drop it. Amazing to think, but even 3M apparently couldn't come up with a satisfactory adhesive that didn't have to be stored wet! That jar with its wet sponge is essential. I'm thinking of buying one; I'll put it into another snap-lid plastic food-storage container with a bit of water, just to be doubly-safe.

Color photo:

Link to PDF that includes info on other things as well as the viewer:

When I called a few years ago, they asked $88 (US).

I trusted the cover gasket on my jar, and it let the water vapor escape over some months of disuse. The dry viewer's adhesive bond was heartbreakingly fragile, and the fluid evaporated in seconds. In a phone call to Arnold a few years ago, they said that their covers are much better. I'm still going to put mine inside another container.

This type of viewer is also available from a Swedish company, iirc for approx. $330 US, iirc! They also have a rectangular version with larger area, at some rather scary price.

Indeed, I'd say that depending upon the value of the data, one would want to consider whether building a reader would be worth the effort.

The Arnold viewer should also show the stripes on plastic cards such as credit cards, and probably floppy discs removed from their housings or jackets.

I'm fairly sure that the Bell System electromechanical phone central offices used seamless rubber belts with magnetic content for analog[ue] voice playback; afaik, the playback head moved to the appropriate track. Voice content was brief messages to the caller.

Conceivable that this belt was used for such a purpose, and that no individual track had enough content to reach the splice. In that event, the belt drive would return it to home position, sensing the hole.

Consider also similar announcing systems for the likes of air terminals and railroad stations.

This could/should be fun!

P.S. : I looked at some other Google hits, and found this:

(Note the scrambled spelling. :) )

I know of Richard Hess, and he knows quite a lot about his business.

"Kyread Magnetic Tape Developer" -- was about 1/5 as costly, but in a spray can.

My Google search string was [arnold Magnetics 1022 magnetic viewer]

HTH!

--
Nicabod =+= Waltham, Mass.
In future decades, will deciphering digital media become
a branch of cryptanalysis?

At the moment, I'd say that it's best not to firmly assume that the recorded info. is necessarily a long helix, so to speak.

However (as I just remembered) brief audio dropouts are not particularly noticeable (see "last-resort" muting in CD playback for coping with corrupted data). I looked more carefully at the photos, and noticed that the splice looks like a butt joint (with a small gap) tape-spliced on the inside.

(Btw, flickr's software has a bug -- it shows only two of the four images from the fancy scrolling selector)

If it has many short tracks and has a homing scheme such as I described in my previous message, the tracks would very likely have visible ends, I'd think. In such a case, they would be parallel to the edge.

I did notice an offer to build a reader. If that's done, the mechanism has to be precise (rollers very close to theoretical cylinders, scrupulously parallel; probably gentle flange on one to keep the belt centered. I don't like the idea of guides, which could easily damage the edges.

instead of making a precision mechanism, perhaps adapt a good-quality unloved inkjet printer for moving the playback head. The print head probably has a nice fine-resolution stepping drive, and perhaps even microstepping to interpolate between steps. It also is likely to have a relatively fine-pitch optical linear encoder (taut plastic strip with fine transverse black lines). As well, the mechanical guides are likely to be quite good -- straightness, repeatability, consistence of position, etc. The gap between print nozzles and paper has to be quite small to get good resolution, and that's not maintained by a servo.

For instance, in an HP DJ(?) 672C, the printhead carrier guide rod must have very tight straightness specs; likewise, the guide rods in an optical (CD/DVD) drive. (As well, spindle runout in a modern HD must be exceedingly small, and the bearings for the head actuator must be really good.)

Of course, the steps are going to be of the wrong size, so if the printer doesn't do microstepping, try to set up a microstepping driver instead of using what's in the printer.

For me, trying to use any of the existing electronics in the printer (other than the power supply) seems formidably difficult, but I'm fairly confident that there are people who know how.

A courteous query to Richard Hess might be very helpful. He's the kind of guy, imho, who might have a quad-head VTR in very good condition, read to run.

Just remembered:

Google on [dead media project] for more. Somebody who was on that list must know exactly what those belts are!

I would welcome e-mail about matters of interest concerning these, but please don't feel obliged. (Please remove the lowered dashes ("underscores")).

Again, HTH!

--
Nicabod =+= Waltham, Mass.
who worked for Sony video tape div. when all of it was open reel
and consumer decks had sliprings

There are many interesting points in both your posts. I don't know if the recording was actually in the form of one long helix or whether it comprised separate tracks, each starting just after the splice. Perhaps the documentation with the belt suggests how it was meant to be recorded, but I don't yet have access to it.

The hole could be there to ensure that the belt begins playing individual messages just after the splice; but splice looks to me as though it might be diagonal, which would knock that theory on the head.

[...]

I had wondered about obtaining a viewer, so thanks for all the info. If the tracks are audio, it would be a simple matter to rig up a transport system and hold a tape head against it by hand just as a first check on how the tracks are arranged.

I have offered to construct a playback machine, but a lot will depend on the economics of the project. If there are dozens of these belts with valuable archives recorded on them, tha cost can be justified; but if there is only one belt with a recording of no particular historic interest, I doubt if it will be worthwhile.

Previous project:

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Very impressive! (As well, an interesting "Dead Medium")

I apologise for being somewhat dismissive in my commentary.

Your work reminds me of a two talented free-lancers I know. One made Vickers hardness-tester diamond indenters, and repaired Rockwell indenters.

The other made a crystal (or just a boule?) puller for synthetic sapphire.

--
Nicabod =+= Waltham, Mass.

It came at an 'interesting time' in world affairs, so I would have expected a lot of valuable historic recordings would start turning up in that format - but so far only the von Manstein trial has been discovered on this side of the pond.

Your comments were most welcome - especially the possibility that the recordings might have been individual announcement tracks which each started from the splice. Nobody else had thought of that.

I have now obtained a littel more information on the belts, including the fact that the splice is slightly skewed, so it seems to be only one long track.

Those projects sound as though they might be more profitable than my line of business. I must find something to make that rich people need....

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk