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

An open-source 240-antenna array to bounce signals off the Moon

moonrf.com

Post reply on HN
Print view View original

41–50 of 72 posts

Re: An open-source 240-antenna array to bounce signals off the Moon

#41

Post by mrtnmcc »

mschuster91 wrote: post #21
Neywiny wrote: post #19

Earlier quoted context omitted.

While true I do worry that it's mandating a pi 5 for each tile? And who knows how specific it is to the 5. Doesn't seem very open relative to something like a usb superspeed, pcie, or 10gbe. USB could be maybe done with the LIFC-33U depending on I/O limitations. PCIe can be done on various FPGAs in the lattice lineup and others. If you use PCIe, theoretically you don't need to reverse engineer how they implemented be…

> While true I do worry that it's mandating a pi 5 for each tile? And who knows how specific it is to the 5. In the multi-tile array it apparently still only needs one Pi [1] as the FPGAs do the heavy lifting. [1] https://moonrf.com/updates/

correct, one Pi-5 for the MoonRF. The beamforming computation is done digitally "on the fly" in round-robin across the sixty QuadRF boards.

Re: An open-source 240-antenna array to bounce signals off the Moon

#42

Post by mrtnmcc »

mschuster91 wrote: post #14

> The target launch price is probably ~$399 (dependent on the tariff landscape over the next month). For that you get the QuadRF tile, an included Raspberry Pi 5, the custom case, tripod, USB-C power supply, cables, and a pre-loaded SD card with a ton of cool SDR applications. Meanwhile... the RPi alone will probably make up 299 dollars of that price tag [1]. It is not a good time to design hardware that needs RAM. A…

The 1 GB RPi-5 is only $45 still, hopefully it stays that way :)

Re: An open-source 240-antenna array to bounce signals off the Moon

#44

Post by jrockway »

blincoln wrote: post #28
HNisCIS wrote: post #4

Earlier quoted context omitted.

I'm struggling to understand the signal chain or antenna architecture here. If those two MAX chips are 2829s this would be 2x2 mimo per tile but I'm not super familiar with that product line and the PCB layout looks like a 4x4 setup. And yeah, the agentic stuff is dumb, I've played a ton with doing low level SDR work on Opus 4.6 and it's truly ass. Also, the "can't radar, plz don't ITAR" is horseshit. Some basic fw t…

> Also, the "can't radar, plz don't ITAR" is horseshit. My assumption is that they're trying to avoid crossing a legal line, as opposed to being personally invested in the idea of preventing radar use by a determined hobbyist.

ITAR feels a lot like Bernstein v. US all over again. Until very recently, everyone who can do anything that would be covered by ITAR was a giant corporation that likes the moat that regulations create, so it's unthinkable to challenge it. But that is changing, just like cryptography was in the early 90s.

Re: An open-source 240-antenna array to bounce signals off the Moon

#45

Post by alexpotato »

tomstokes wrote: post #34
infinitewars wrote: post #2

Wild hardware flex for a garage project. Reverse-engineering the Pi 5's MIPI to push 5.6 Gbps from custom MASH sigma-delta ADCs to a Lattice ECP5 FPGA to the Raspberry Pi is serious engineering. The idea that the RF receiver looks like a "camera" to the Pi while the transmitter is a "display" is super creative. Getting a 1.5 kW, 240-antenna EME array for $2,499 is actually cheap for something like this. Their standal…

> Reverse-engineering the Pi 5's MIPI to push 5.6 Gbps from custom MASH sigma-delta ADCs to a Lattice ECP5 FPGA to the Raspberry Pi is serious engineering Using video interfaces to transfer arbitrary data at high speeds is becoming a common trick for cheap boards with limited interfaces. Video inputs and outputs are generally highly mature and optimized to avoid dropping frames because everyone wants reliable video.…

> Using video interfaces to transfer arbitrary data at high speeds is becoming a common trick for cheap boards with limited interfaces.

There is a line in the book Accelerando about how evolution did this with biological vision.

It's basically the highest bandwidth sense we have and evolved AFTER smell (chemical based) and auditory (gas pressure based) senses.

Re: An open-source 240-antenna array to bounce signals off the Moon

#46

Post by ceejayoz »

thomashabets2 wrote: post #23
ceejayoz wrote: post #16

Earlier quoted context omitted.

Any that forbid or restrict satellite comms? Don’t use this in Iran.

I'm pretty sure the "country restrictions" are about ITAR, not the destination country regulation. When the page says "uh… do not use this to build a phased array radar… even though you could. And if you do, then in no way were we involved. Just don't", this is extremely likely to be about ITAR.

> License: Amateur Radio (Technician+) to operate, country restrictions apply.

This implies it's about operating a radio transmitter.

Iran will absolutely frown on that right now, as they've frowned on Starlink. Their internet shutoff indicates "empowering the public to connect across the world" is not really what they want.

Re: An open-source 240-antenna array to bounce signals off the Moon

#47

Post by CamelCaseCondo »

jacquesm wrote: post #33

I don't think you should call something 'open source' until you've released the source, but other than that this is an extremely impressive project. HAM's have been doing EME since forever ( https://en.wikipedia.org/wiki/Earth%E2%80%93Moon%E2%80%93Ear... ), it is a very neat trick. It almost looks as if the EME bounce capability of this antenna is a fig leaf or an afterthought, my own 'applications' list would be a l…

Apparently it’s a way to attract attention and support. I’ve been following picoIDE which got some attention here on HN 4 months ago [1]. When asked then where the src is, the answer was in a few weeks. Fast-forward a crowd-supply campaign (no mention 4 months ago) to the tune of 350k and the repo is still empty.

[1] https://news.ycombinator.com/item?id=45949352

Re: An open-source 240-antenna array to bounce signals off the Moon

#48

Post by mrtnmcc »

jacquesm wrote: post #33

I don't think you should call something 'open source' until you've released the source, but other than that this is an extremely impressive project. HAM's have been doing EME since forever ( https://en.wikipedia.org/wiki/Earth%E2%80%93Moon%E2%80%93Ear... ), it is a very neat trick. It almost looks as if the EME bounce capability of this antenna is a fig leaf or an afterthought, my own 'applications' list would be a l…

It's open source. Here is the GitHub: https://github.com/open-space-sdr/main

Re: An open-source 240-antenna array to bounce signals off the Moon

#49

Post by wolvoleo »

Pretty cool. And expensive. It's pretty amazing how starlink sells basically this for $200. Pretty sure they subsidize it.

Ps you don't really need this. A phased array is great for communicating with or tracking fast moving objects. For something as slow as the moon a simple parabolic dish, either manually aimed or with an az/el motor will be more cost-effective. Motors get expensive too with wind and rain and longevity (moving around 24/7) but hams don't moonbounce constantly.

Starlink sats move really quickly through the night sky and it tracks multiple so you don't have interruptions this is why for that purpose a phased array is great. For incidental ham use to the moon it's very interesting tech but not exactly necessary.

Re: An open-source 240-antenna array to bounce signals off the Moon

#50

Post by infinitewars »

wolvoleo wrote: post #49

Pretty cool. And expensive. It's pretty amazing how starlink sells basically this for $200. Pretty sure they subsidize it. Ps you don't really need this. A phased array is great for communicating with or tracking fast moving objects. For something as slow as the moon a simple parabolic dish, either manually aimed or with an az/el motor will be more cost-effective. Motors get expensive too with wind and rain and longe…

Well this is roughly 2 thousand times higher power than a Starlink user terminal.

Aand of course it's open source, https://github.com/open-space-sdr/main/

Post reply on HN