Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Radio Amateur Copies Signal from Mars-Orbiting Satellite

arrl.org

Post reply on HN
Print view View original

11–20 of 41 posts

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#11

Post by madengr »

schoen wrote: post #9
zokier wrote: post #5

> He uses a homemade 60-centimeter dish that seems surprisingly small. overall, impressive feat. would be interesting to know more about the gear. from the posted video, I guess he is using ettus b200, but thats just a guess.

Apparently the Deep Space Network dishes are (now up to) 34 meters: https://www.nasa.gov/feature/jpl/nasa-s-deep-space-network-w... I guess they achieve higher reliability than amateurs on a number of counts, but that contrast also makes the amateur efforts seem even more impressive. (Since area is proportional to the square of diameter, the DSN dishes would each be over 3,000 times larger than Scott Tilley's dish.)

He is detecting, not demodulating, which is what the big dishes are for. Most deep space comms have carrier leakage (on purpose) for ranging. That’s likely what he is detecting.

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#12

Post by myth2018 »

wrycoder wrote: post #4
myth2018 wrote: post #2

Wow, I'm a ham radio operator and today during Perseverance landing I was wondering if it would be possible to receive signals from orbiters on Mars using homemade equipment. Now I have my answer.

And his dish is only 60 cm dia.

Those 60 cm are probably enough for his requirements. It seems that he's mainly interested on detecting signal presence, but not necessarily demodulating it. Then, I suppose that the signal-to-noise ratio provided by his small dish is sufficient

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#13

Post by myth2018 »

schoen wrote: post #9
zokier wrote: post #5

> He uses a homemade 60-centimeter dish that seems surprisingly small. overall, impressive feat. would be interesting to know more about the gear. from the posted video, I guess he is using ettus b200, but thats just a guess.

Apparently the Deep Space Network dishes are (now up to) 34 meters: https://www.nasa.gov/feature/jpl/nasa-s-deep-space-network-w... I guess they achieve higher reliability than amateurs on a number of counts, but that contrast also makes the amateur efforts seem even more impressive. (Since area is proportional to the square of diameter, the DSN dishes would each be over 3,000 times larger than Scott Tilley's dish.)

Indeed, but there are other important factors besides size.

DSN have way bigger requirements in terms of signal to noise ratios, since they need to demodulate received signals.

Scott Tilley, on the other hand, seems to be mainly interested on detecting the presence of signals, not necessarily extracting information from it. Then, he could build a bigger dish, but he doesn't actually need one to achieve his goal.

I notice that another guy commented here about that. His comment is dead now, but he had a point. I found it informative indeed, I've always asked myself why spacecrafts "wasted" energy with carriers and never realized they make the signal easer to find.

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#14

Post by mhh__ »

geocrasher wrote: post #7

This is nothing short of incredible. Radio is hard, even at HF (1-30mhz). It's very forgiving at HF though, and so is very approachable. This is where I spend my ham radio time dabbling and hacking away at things. VHF is harder, and UHF an order of magnitude harder. But 8-12Ghz? That's not for mere mortals. It's machining pieces at tight tolerances and movement measured in the smallest fractions. If this is what he d…

You have to make a blood sacrifice to the Voodoo gods in high speed electronics if you want it to work (is the saying, anyway) - i.e. the actual shape of the traces on the PCB starts to become important, and one can use this fact to form things like filters and directional couplers.

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#15

Post by schoen »

myth2018 wrote: post #13
schoen wrote: post #9

Earlier quoted context omitted.

Apparently the Deep Space Network dishes are (now up to) 34 meters: https://www.nasa.gov/feature/jpl/nasa-s-deep-space-network-w... I guess they achieve higher reliability than amateurs on a number of counts, but that contrast also makes the amateur efforts seem even more impressive. (Since area is proportional to the square of diameter, the DSN dishes would each be over 3,000 times larger than Scott Tilley's dish.)

Indeed, but there are other important factors besides size. DSN have way bigger requirements in terms of signal to noise ratios, since they need to demodulate received signals. Scott Tilley, on the other hand, seems to be mainly interested on detecting the presence of signals, not necessarily extracting information from it. Then, he could build a bigger dish, but he doesn't actually need one to achieve his goal. I no…

Thanks for that clarification (to you and the author of the dead sibling comment)!

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#16

Post by suifbwish »

zokier wrote: post #5

> He uses a homemade 60-centimeter dish that seems surprisingly small. overall, impressive feat. would be interesting to know more about the gear. from the posted video, I guess he is using ettus b200, but thats just a guess.

60 cm of near infinite resolution is still a crazy amount of data

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#17

Post by jackyinger »

floatingatoll wrote: post #3

I wonder if ARRL knows there’s malicious ads on their site. Reader mode saves the day!

I can confirm that I got some sketchy stuff from this site. It showed me an I’m not a robot butting which I stupidly clicked. Went and cycled my passwords to be safe.

Flagged the post as a result.

Re: Radio Amateur Copies Signal from Mars-Orbiting Satellite

#18

Post by jjulius »

geocrasher wrote: post #7

This is nothing short of incredible. Radio is hard, even at HF (1-30mhz). It's very forgiving at HF though, and so is very approachable. This is where I spend my ham radio time dabbling and hacking away at things. VHF is harder, and UHF an order of magnitude harder. But 8-12Ghz? That's not for mere mortals. It's machining pieces at tight tolerances and movement measured in the smallest fractions. If this is what he d…

>If this is what he does for fun, I wonder what he does for work?

He does electrical work for boats.

https://youtu.be/hMsE1rxeOw4

Post reply on HN