4 ms·

> even though there was no computer on Earth at the time fast enough to decode it I'm not sure what is meant by that. Not fast enough to decode in real time?

> even though there was no computer on Earth at the time fast enough to decode it I'm not sure what is meant by that. Not fast enough to decode in real time? There is/was no need to do that. The transmissions would have gone to tape in any case. Here is a link describing how to decode such a tape: https://destevez.net/2021/09/decoding-voyager-1/ https://destevez.net/2021/09/decoding-voyager-1/

throwup238 3y ago
TFA: >I will use a recording that was done back in 30 December 2015 with the Green Bank Telescope in the context of the Breakthrough Listen project. That recording was made in 2015 on a modern radio telescope, it is not from a tape. The GP has the details wrong though: when the Voyager design was finalized in the early 70s with the Viterbi encoder, there wasn’t enough computational power to decode the signal. By the time it launched in ‘77, there was enough and it launched with the Viterbi encoder enabled.
- Gibbon1 3y ago
  I wrote test firmware for a very early spread spectrum transceiver that used something close to Viterbi encoding. It consumed 220mA in receive mode and 60-120mA in transmit mode. I was told some of that was the RF amps and ADC but a lot of it was the decoder.
apitman 3y ago
I called it a legend deliberately. One of the things I love about this anecdote is that it makes less sense the older and more experienced I get. It was told to me 12 years ago as a young, starry-eyed junior developer by my supervisor who had a PhD in RF research, while we were working on what we considered to be a world-changing wireless technology at a startup in San Francisco (it wasn't). Who knows how many of the details I misinterpreted or am misremembering, or that he was. Where did he hear it originally? Maybe a grizzled old professor who worked directly on the project? Maybe a TA who made up the whole thing? Whether true or not, it inspired me then as it does now to strive to be a better engineer, to think outside the box, to attempt hard things. I continue sharing it hoping that one day Cunningham's Law will take effect and someone will share the correct details. But there's also a part of me that hopes that never happens.
- thih9 3y ago
  When I read the earlier comment, seeing “tech legend” didn’t make me assume that the story would be false. Grandparent’s clarification was helpful for me.
- DonHopkins 3y ago
  Sounds like that old legend that the Cray 1 could execute an infinite loop in 7.6 seconds!

throwup238 3y ago

TFA: >I will use a recording that was done back in 30 December 2015 with the Green Bank Telescope in the context of the Breakthrough Listen project. That recording was made in 2015 on a modern radio telescope, it is not from a tape. The GP has the details wrong though: when the Voyager design was finalized in the early 70s with the Viterbi encoder, there wasn’t enough computational power to decode the signal. By the time it launched in ‘77, there was enough and it launched with the Viterbi encoder enabled.

Gibbon1 3y ago
I wrote test firmware for a very early spread spectrum transceiver that used something close to Viterbi encoding. It consumed 220mA in receive mode and 60-120mA in transmit mode. I was told some of that was the RF amps and ADC but a lot of it was the decoder.

apitman 3y ago

I called it a legend deliberately. One of the things I love about this anecdote is that it makes less sense the older and more experienced I get. It was told to me 12 years ago as a young, starry-eyed junior developer by my supervisor who had a PhD in RF research, while we were working on what we considered to be a world-changing wireless technology at a startup in San Francisco (it wasn't). Who knows how many of the details I misinterpreted or am misremembering, or that he was. Where did he hear it originally? Maybe a grizzled old professor who worked directly on the project? Maybe a TA who made up the whole thing? Whether true or not, it inspired me then as it does now to strive to be a better engineer, to think outside the box, to attempt hard things. I continue sharing it hoping that one day Cunningham's Law will take effect and someone will share the correct details. But there's also a part of me that hopes that never happens.

thih9 3y ago
When I read the earlier comment, seeing “tech legend” didn’t make me assume that the story would be false. Grandparent’s clarification was helpful for me.
DonHopkins 3y ago
Sounds like that old legend that the Cray 1 could execute an infinite loop in 7.6 seconds!