Not impossible, just extremely difficult. I'm a ham and getting some contacts over moonbounce is a personal goal of mine. Historically this kind of thing has required some pretty large antenna arrays and very high power though:
It's been being done for 70 years or so. You just need to be able to generate quite a lot of power on VHF upwards, and have a very low-noise antenna preamp, and a large array of directional aerials to focus the signal.
If you're reasonably handy with simple hand tools you can build a moonbounce array for a couple of thousand and a month or so of evenings.
The big dish antenna at Stanford University (visible from I-280) was, among many other things, used to monitor Soviet radar signals from Sary Shagan in Kazakhstan, that bounced off the moon some of the time.
which has this tidbit which explains why it works as well as it does when it works:
"Fortunately for us, the moon appears only slightly rough to radio waves; most of the reflected energy comes back from an area at the near point just a few miles in diameter. The bulk of the energy striking farther around on the side is reflected out into space and never returns to earth."
Yeah... so free space path loss at legal frequencies for hams this thing can transmit on is ~283dB. Neat idea but consider me skeptical. Having said that I can see some interesting applications for this kind of gear, EME seems overly optimistic though.
I got to see this in person at pacificon a few weeks ago. Also the creator is my friend from UIUC who I consider a brilliant rf/DSP engineer.
The demo was able to show and end to end tx chain from gnuradio to a receiver.
Really excited to see this! As there are a myriad of other things that this hardware can be used for as well.
If the goal is only to communicate with people on the other side of the world, HF ionosphere skip can do that with cheap 100-year-old technology (although transistors make it easier).
I assume the goal is to do something cooler than that.
That's very impressive and I'm even more impressed if you can manage to sell tiles at that low price.
PA looks suspiciously similar to SE5004L. I just needed some for my own projects but every distributor is out of stock. I wonder if this is where all of them went?
I’d wondered about using moon bouncing in order to distribute video streaming keys (piracy) in a way which would make it impossible to locate the sender. Unlikely to be viable at scale, as the moon isn’t always visible, but it’s an intriguing covert broadcast mechanism.
Really cool phased array. However, I don't think this will really make EME more accessible when their EME version is $2499+. Maybe the 4 element version would be fun to play around with.
While it isn't exactly communication, the Moon is not the only planetary body of which signals have been bounced off. Radar is workable within the solar system, including the moons and rings of the outer planets.
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[ 740 ms ] story [ 172 ms ] threadhttps://hamradio.engineering/eme-moonbounce-bouncing-signals...
http://www.g4ztr.co.uk/app/download/13284489/RaCcom_Feb14+EM...
http://www.g4ztr.co.uk/app/download/13300096/Radcom_Mar144+E...
If you're reasonably handy with simple hand tools you can build a moonbounce array for a couple of thousand and a month or so of evenings.
The wikipedia article:
https://en.wikipedia.org/wiki/Stanford_Dish
links to:
https://web.archive.org/web/20201108114110/https://www.cia.g...
which has this tidbit which explains why it works as well as it does when it works:
"Fortunately for us, the moon appears only slightly rough to radio waves; most of the reflected energy comes back from an area at the near point just a few miles in diameter. The bulk of the energy striking farther around on the side is reflected out into space and never returns to earth."
Tx power: 1 W per antenna
Yeah... so free space path loss at legal frequencies for hams this thing can transmit on is ~283dB. Neat idea but consider me skeptical. Having said that I can see some interesting applications for this kind of gear, EME seems overly optimistic though.
Announced on the EME Facebook Group: https://www.facebook.com/share/p/19zLsGZiE7/?mibextid=wwXIfr
Output power was 500w
The demo was able to show and end to end tx chain from gnuradio to a receiver. Really excited to see this! As there are a myriad of other things that this hardware can be used for as well.
I assume the goal is to do something cooler than that.
PA looks suspiciously similar to SE5004L. I just needed some for my own projects but every distributor is out of stock. I wonder if this is where all of them went?
Wonder how they prevent usage as radar as this thing could pretty much be a drop-in missile seeker.
https://www.jpl.nasa.gov/news/radar-astronomy-used-to-resear... (1991)