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System Bus Radio: Transmits AM radio on computers without transmitting hardware

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Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#11

Post by mark-r »

braythwayt wrote: post #8
mark-r wrote: post #6

Earlier quoted context omitted.

I saw it done in the 1970s on a PDP-8 at the University of Minnesota. It wasn't just a couple of tones, it was playing complete songs. Later on a Z80 micro. Computers really emitted a lot of RF back then!

For good tones, you had to get down close to "the metal." I recall that there were a few programs like this, but I believe they were written in assembler or machine language so as to control the cpu and bus directly.

Back then most programming for those machines was done at that level!

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#12

Post by braythwayt »

godelmachine wrote: post #10
braythwayt wrote: post #5

In the 1970s, I read about people doing this at MIT or some such, on real computers. Our high school had a Nova 1220 minicomputer, but we had no access to assembly for it, so all I could do was write programs in BASIC. After a bit of experimentation, I was able to produce two or three distinct tones of discordant buzzing with loops. Computer music!

I think you are referring to "Foot on the Hill" being played on that Altair 8800, which cunningly made use of the radio frequency interference/ static controlled by the timing loops by the program - created by Steve Dompier . Bill Gates was confounded and astounded, and described it as, "the best demo program I've seen for the Altair…". He could not figure out how the computer could broadcast to the radio. You can re…

I seem to recall reading about this running on minicomputers or mainframes, as described in another reply, and I also think this predated the Altair, as I first became smitten with computers around 1972.

Here's a video of a minicomputer generating AM radio music in 1971:

https://www.youtube.com/watch?v=akvSE5Z474c&lc=D5Mdy7u7Cxwsk...

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#13

Post by zenkat »

Zenst wrote: post #3
dvaita99 wrote: post #2

Can you someone do a ELI5 on this project? Tried to read but couldn't move further.

Computers emit radio waves, by varying the processing upon the computer you can influence those emissions. Thus you are able to control those emissions and produce a radio signal you can pick up upon a standard radio.

What part of the computer is emitting the radiation? And how is this program manipulating it to generate a song?

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#14

Post by braythwayt »

mark-r wrote: post #11
braythwayt wrote: post #8

Earlier quoted context omitted.

For good tones, you had to get down close to "the metal." I recall that there were a few programs like this, but I believe they were written in assembler or machine language so as to control the cpu and bus directly.

Back then most programming for those machines was done at that level!

When I first laid eyes on the "High Speed Job Stream" in UofT's Sanford Fleming building (that particular building has since burnt down and been replaced), students were running jobs in PL/1, WATFIV, LISP, SPITBOL, COBOL, and many others.

In the labs, there were IBM Selectric terminals dedicated to APL.

And there was a BASIC dialect over at what was then "Ryerson Polytechnic." There was a room with terminals and acoustic couplers, no security to keep you out.

You need a username and password to use the terminals, but the username and password for each class was posted on a corkboard, so you would write your own programs as long as you didn't get in the way of actual students trying to finish their assignments.

I don't doubt that "most" programming was done in assembler, but there was no shortage of higher-level programming going on.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#17

Post by univacky »

godelmachine wrote: post #10
braythwayt wrote: post #5

In the 1970s, I read about people doing this at MIT or some such, on real computers. Our high school had a Nova 1220 minicomputer, but we had no access to assembly for it, so all I could do was write programs in BASIC. After a bit of experimentation, I was able to produce two or three distinct tones of discordant buzzing with loops. Computer music!

I think you are referring to "Foot on the Hill" being played on that Altair 8800, which cunningly made use of the radio frequency interference/ static controlled by the timing loops by the program - created by Steve Dompier . Bill Gates was confounded and astounded, and described it as, "the best demo program I've seen for the Altair…". He could not figure out how the computer could broadcast to the radio. You can re…

You can watch and listen to it on an Altair 8800b and get the octal object code for toggling into your own Altar here: => https://www.youtube.com/watch?v=fgYhVnmeWrk

PDP-8 music here => https://www.youtube.com/watch?v=vfx5H7ikA7Y

DECUS documentation entry for "PDP-8 MUSIC PLAYING PROGRAM" available on punch tape, 1976; written in assembly (PAL8) and fit in 4K words (12 bit word) of core memory. Worth a read. => http://www.pdp8online.com/miscdocs/DECUS/Decus%208-804_MUSIC...

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#18

Post by univacky »

braythwayt wrote: post #12
godelmachine wrote: post #10

Earlier quoted context omitted.

I think you are referring to "Foot on the Hill" being played on that Altair 8800, which cunningly made use of the radio frequency interference/ static controlled by the timing loops by the program - created by Steve Dompier . Bill Gates was confounded and astounded, and described it as, "the best demo program I've seen for the Altair…". He could not figure out how the computer could broadcast to the radio. You can re…

I seem to recall reading about this running on minicomputers or mainframes, as described in another reply, and I also think this predated the Altair, as I first became smitten with computers around 1972. Here's a video of a minicomputer generating AM radio music in 1971: https://www.youtube.com/watch?v=akvSE5Z474c&lc=D5Mdy7u7Cxwsk...

I think that computer was built in 1971; the video mentions that the software used is Richard Wilson's player, which was written in 1975 (the DECUS entry is dated 2/11/1976).

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#19

Post by godelmachine »

zenkat wrote: post #13
Zenst wrote: post #3

Earlier quoted context omitted.

Computers emit radio waves, by varying the processing upon the computer you can influence those emissions. Thus you are able to control those emissions and produce a radio signal you can pick up upon a standard radio.

What part of the computer is emitting the radiation? And how is this program manipulating it to generate a song?

The CPU colloquially called the processor does this. When you feed a program to the CPU, it switches between logic gates (read - transistors turning on and off), to process the program. As the processing elements switch between power levels of 0 and 1 (0V & 5V / 0V & 12 V), there are electromagnetic fluctuations.

These EM fluctuations are the emmissions we are talking about here.

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