How to talk to a 36-year-old space probe with GNU Radio, a USRP and a big dish

http://www.jmalsbury.com/how-to-talk-to-a-36-year-old-space-probe-isee-3-with-gnu-radio-a-usrp-and-a-big-dish/

by liotier • 12 years ago

226 18 12 years ago

pronoiac• 12 years ago

Oh cool! They presented this at Dorkbot-SF a couple of weeks ago. A bit I particularly liked was that, because of the relative speed of the probe, a couple of km/sec, the frequencies sent and received had to be separately adjusted. And also, Arecibo was broadcasting with enough power to boil birds that flew over it.

It's cool space shit, is what I'm saying.

Edit: here's some video: https://www.youtube.com/watch?v=NTljlMH-0oM

smoyer• 12 years ago

"Arecibo was broadcasting with enough power to boil birds that flew over it"

Birds that flew over the parabola of the antenna or birds that flew between the focal point and the parabola? I can't imagine the amount of energy the former would take (and the latter is impressive by itself)!

spitfire• 12 years ago

Same thing with the Mig-21 radar, and I presume other fighters. If they powered it up on the ground, bird would drop.

During WWII, soldiers would stand in front of the radar to keep warm. This was before health and safety.

batbomb• 12 years ago

if you think that's crazy, you should know an experiment I worked on had approval to fire an electron accelerator directly into the sky. Of course, we called it an "electron light source".

wyager• 12 years ago

Oh man. This is such a cool example of how open software platforms have made the world more accessible. Imagine how hard it would have been to rig up that modulation system from scratch 30 years ago.

Also, this article made me realize how you can do frequency addition/multiplication on arbitrary signals via complex multiplication/exponentiation! That part of the flow graph really confused me for a bit. So cool!

tommi• 12 years ago

Some glossary to make it easier to read:

USRP, Universal Software Radio Perhipheral - https://en.wikipedia.org/wiki/Universal_Software_Radio_Perip...

SDR, Software Defined Radio - https://en.wikipedia.org/wiki/Software-defined_radio

frozenport• 12 years ago

I got to get me one of those Arecibo dishes! I'm still impressed that they were able to get access to it.

BuildTheRobots• 12 years ago

Looks like we've already thrashed his server (oom errors); so here's a link to a cached version for the lazy: http://webcache.googleusercontent.com/search?q=cache:Qhe6rYL...

mellisarob• 12 years ago

it was amazing the way they accessed it

callesgg• 12 years ago

The hole thing they are doing is very cool and they write and post allot of stuff.

Unfortunately most of the text they post is quite boring and detail less.

It would be nice if they added someone new to the team that was a better writer.

How to talk to a 36-year-old space probe with GNU Radio, a USRP and a big dish

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