back to article LoRa to the Moon and back: Messages bounced off lunar surface using off-the-shelf hardware

A team of scientists has managed to bounce a LoRa message off the Moon, setting an impressive record of 730,360km for the furthest distance such a data message has travelled. While much of the technology was off-the-shelf (Semtech's LR1110 RF transceiver chip was used) the signal was amplified to 350w using the 25-metre dish …

  1. IanRS

    Off the shelf equipment?

    Some people must have large shelves if they have a 25m radio dish sitting around on one.

    1. imanidiot Silver badge

      Re: Off the shelf equipment?

      Possibly unique in the world. The dish they're using was originally built for scientific research (and was the largest in the world for a bit). In 2007 it was given to a group of amateur radio astronomers and they've spent a lot of time rebuilding the dish and making the whole thing operational again. Since iirc 2016 the radiotelescope is now available for amateur radioastronomers and other people interested in doing something with large dish like that who can convince the people running it that what they want to do makes sense and won't break the thing (barring apparently some internal kerfuffles within the organisation running the scope and the whole global virus stuff).

      See also: www.camras.nl and the wiki page on the Dwingeloo radio telescope

      1. ICL1900-G3 Bronze badge

        Re: Off the shelf equipment?

        Brilliant. Just brillant.

  2. Doctor Syntax Silver badge

    Great range, pity about the laency.

    1. Anonymous Coward
      Coat

      So you're saying even if I get a 25m telescope it's no good for Doom?

  3. Neil Barnes Silver badge

    At least with Venus

    You've probably got time for a cuppa between sending and receiving. Even at it's closest distance, it's a five minute round trip so there's at least time to get the kettle on.

    1. herman Silver badge

      Re: At least with Venus

      Err… Five minutes for very small values of a minute.

      1. Neil Barnes Silver badge

        Re: At least with Venus

        Ach, my bad: I read closest approach of 40M km as 40M miles.

        Call it a quarter of an AU; about two minutes each way. So still time to get the kettle on.

  4. Primus Secundus Tertius Silver badge

    It would help if the article briefly explained what LoRa was, instead of assuming we would Google it.

    1. My other car WAS an IAV Stryker

      Not Google

      I always go straight to Wikipedia. I don't need to maintain a search history of random knowledge and trivia. Google mixes the results with So Many Ads these days that I can't find info I need.

  5. Naich

    "...we transmit, immediately switch to the receive mode and receive our own message back."

    So it's basically data storage.

    1. Mast1

      Health & Safety would love it: at least it would be safer than mercury delay line storage.

      https://www.computerhistory.org/storageengine/edsac-computer-employs-delay-line-storage/

      Extra terrestrials might see it as another piece of space "junk"......

  6. Spoobistle
    Holmes

    EME (Moonbounce)

    Radio hams have been doing this for years, without needing 25m dishes, and using equipment that fits into the average back garden. The RSGB has a page for anyone interested.

    1. Dafyd Colquhoun

      Re: EME (Moonbounce)

      The stuff doesn't even have to fit in a garden. I witnessed 10 GHz moonbounce between Queensland and Texas at a ham radio conference. VERY shallow angles, but a 30cm antenna has good gain, and when driven with a 50W amplifier put out a big signal.

      Lora over that distance is impressive. Getting up there with Joe Taylor (K1JT) work using Arecibo. 61dBi gain at 433 MHz is massive, and that allowed one other party to use a handheld radio with a rubber ducky (or so is claimed). Believable since the spot size of the beam was 1/2 the diameter of the moon. https://physics.princeton.edu/pulsar/k1jt/Moonbounce_at_Arecibo.pdf

      1. My other car WAS an IAV Stryker
        Facepalm

        Re: EME (Moonbounce)

        Darn you... You said "radio" and "rubber duck(y)" in the same sentence and my mind immediately went to "CB radio" and the song "Convoy".

        (The music of which -- as I've said long ago -- was written by Chip Davis, leader/arranger/composer for Mannheim Steamroller; given the season, it's time to warm up the Steamroller's Christmas playlist.)

        1. Evil Scot

          Re: EME (Moonbounce)

          OMAHA!!!!!

          (Multiple exclamation marks because thanks for the ear worm)

        2. Zebo-the-Fat

          Re: EME (Moonbounce)

          Rubber ducky is a rubber (or plastic) covered helical antenna usually used on hand held mobile radios

    2. Antron Argaiv Silver badge

      Re: EME (Moonbounce)

      I happen to have a friend in the broadcast business.

      When his station was converting from analog to DTV, he was managing the project to strengthen the existing tower and another project to design the new DTV antenna, to be shared by a number of broadcasters using the tower.

      He also happens to be a radio ham. His plan was, during the weekend after the antenna was mounted, but before all the users powered up, to attach a 440MHz ham radio to the feedline and see who he could work.

      Sadly, the schedule didn't work out. I can see much the same thing going on here. I wonder how many of those involved were (or had been at one time) hams

      I admire the investigators who managed to write a project proposal and succeeded in getting time on the dish for this experiment.

      1. werdsmith Silver badge

        Re: EME (Moonbounce)

        Bit of a mismatch there, will need to use ATU for the 40MHz + difference.

        But anyway, in the UK 70cms is so quiet these days, even repeaters are asleep most of the time.

    3. herman Silver badge

      Re: EME (Moonbounce)

      One can bounce off of lots of things - the space station - an aircraft - space junk - meteor trails...

  7. Detective Emil
    Headmaster

    Please, Sir …

    What's LoRa?

    1. Arthur the cat Silver badge
      Trollface

      Re: Please, Sir …

      Does this help?

      1. Version 1.0 Silver badge
        Happy

        Re: Please, Sir …

        "Does this help?" - not really but all your down votes demonstrate that the majority of El Reg readers have decent brains and want to find out the technical information about everything ... that's why we are all here and not on social media. LOL so you have made a good point.

        1. ICL1900-G3 Bronze badge

          Re: Please, Sir …

          I thought this was social media... for largely unsociable grown-ups.

          1. Wellyboot Silver badge
            Pint

            Re: Please, Sir …

            As a grumpy old techie I'd describe it as a modern BBS.

            Have one of these, today is one of the best Fridays for knocking off early :)

    2. vtcodger Silver badge

      Re: Please, Sir …

      Reasonable question -- deserves an answer.

      LoRa is a proprietary spread spectrum technology that is used in license free bands. It presumably allows multiple user pairs to communicate over the same band simultaneously without requiring them to find a free frequency slot. The Wikipedia article is at https://en.wikipedia.org/wiki/LoRa

      There's also a Wikipedia article on EME (Earth Moon Earth) communications in general at https://en.wikipedia.org/wiki/Earth%E2%80%93Moon%E2%80%93Earth_communication

  8. Arthur the cat Silver badge

    "low power, low cost and very very small"

    the signal was amplified to 350w using the 25-metre dish

    Yep, nothing says "low power, low cost and very very small" more than that.

    1. swm Silver badge

      Re: "low power, low cost and very very small"

      "the signal was amplified to 350w using the 25-metre dish"

      350 watts is 350 watts. I think they are comparing the power of an omni-directional antenna with a beam which has a db gain if you are within the beam.

  9. A Non e-mouse Silver badge
    Joke

    Size Matters

    This is low bandwidth stuff, but also low power, low cost and very very small

    If a 25m dish hooked up to a 350w transmitter is low power and very very small, I'd hate to see what high power or "big" is!

    1. Antron Argaiv Silver badge
      Facepalm

      Re: Size Matters

      also...Far Away!

    2. John Sager

      Re: Size Matters

      I'd hate to see what high power or "big" is!

      Talk to NASA. They have done Marsbounce with the Deep Space Network and Arecibo before it died. Possibly Venusbounce and Mercurybounce too.

  10. Pete 2 Silver badge

    What would be more interesting ...

    ... is if they had got a reply!

  11. Antron Argaiv Silver badge
    Facepalm

    You know what they say

    When all you have is a 25m dish, you start looking around for things to hook up to it!

    1. Arthur the cat Silver badge

      Re: You know what they say

      Or cook a humungous stir fry.

  12. Anonymous Coward
    Anonymous Coward

    Whuuu?

    "We could actually see the sphere of the Moon simply by looking at the message that was echoed back to us"

    OK, someone far, far brighter than me is going to have to explain this in simple steps and terms (and maybe ASCII art). Anyone?

    +1 for the impressive science though.

    1. Tomislav

      Re: Whuuu?

      I believe a LEGO reenactment would be better and more in El Reg style. :)

    2. vtcodger Silver badge

      Re: Whuuu?

      Not that complicated if you've ever had to look at radar return waveforms. A bit puzzling if not.

      If the moon were a glassy smooth sphere, you'd only get one return signal -- from the center of the moon. Any other reflections would go off to your sides. But the moon is bumpy. Craters and such. So in addition to the return from the center point, you'll get some signal bounced back from other lunar features. Those are further away from you than the center of the moon. It takes a tiny bit longer for your signal to get to them and a bit longer for the signal reflected from them to get back. Result: instead of one tidy set of pulses that is mirror image of your outgoing signal, you'll get a reflected signal that's smeared out over (I'd guess) 20 or so milliseconds.

      I may have some of the details wrong. It's not like I spend my spare time bouncing radio signals off the moon. But I think the above is the general idea.

      1. swm Silver badge

        Re: Whuuu?

        You also get information from the different frequency shifts due to the (slight) rotation of the moon. So you get radial information from the center because of the delay and "left to right" information from the frequency shifts. Doing this several times allows one to disambiguate various areas and get a radar picture of the whole moon.

  13. nobody1111

    As worded this isn't really anything special. Ham radio operators have been doing this for decades and with smaller antennas. Some just by leaning a Yagi against the garden fence.

    I suspect ignorance on the reporters part, though. A signal is not "amplified to 350w using the 25-metre dish of the Dwingeloo Radio Observatory in the Netherlands" just by changing the antenna. A more likely case is that a couple of milliwatts sent through the dish had an ERP (effective radiated power) equivalent to a 350 watt sent to a dipole. A pretty good accomplishment but hardly headline worthy.

    Come back to us when you are doing it through a a handheld Yagi.

    1. werdsmith Silver badge

      Ham radio operators have been doing moon bounce since long before I read about it in RadCom back in the last millenium, true. But with reading back data, bouncing off a pretty rapidly shifting moon? A dopplering reflector? That's a bit more tricky than a CW contact.

      1. PyroBrit
        Thumb Up

        EME, LORA and Meteor Scatter

        Yep, first read of the story didn't say anything spectacular. In the HAM world, we have done this for quite a while with some cheap gear.

        I don't see a mention on the Frequency used by Lora and considering the modules are available in 433Mhz, 868Mhz and 915Mhz, it may make a difference. Certainly 433Mhz would be quickest to get working with a borrowed ham yagi and suitable amp.

        Might be harder with 915Mhz but i've not read up on the propagation properties of this frequency at distance. Normally higher frequency = less penetration.

        What I find more of an achievement is the use of Meteor Scatter for communications. Bouncing your radio signal off of the ionised trail of a meteor passing through the upper atmosphere when that trail may only last from a few seconds to 30 seconds.

      2. Antron Argaiv Silver badge

        Had to know this stuff for my Amateur Extra class exam. Two sources of frequency shift: one due to the orbit and one due to the rotation.

  14. Dizzy Dwarf

    Short message

    I hope it was: Sod it, the bloody thing's stuck again

    1. Androgynous Cupboard Silver badge

      Re: Short message

      I've been doing lots of mucking around with LoRa - the things that most people seem to use it for when testing are either the current temperature, or paxcounter.

      If the latter I trust we can presume the number of persons detected was zero...

      1. herman Silver badge

        Re: Short message

        Listening to aircraft ADSB is more fun than counting how many gadgets in a geek’s pockets.

  15. We're all in it together

    Research first before acting

    Bought two LoRa modules from the Pihut - one plugged into my Pi4, the other via my mobile running a terminal app. Wrote a bash script to send a message every second with timestamp, and set the mobile to receive. Walked about five miles away from home.

    What I should have done is checked the ground profile first, as my route after a quarter of a mile blocked the signal due to terrain. Haven't bothered since but intend to plan the next route. As I have a relative perched on a hill in Ryde, Isle of Wight, I'd like to see if it would work over on the ferry to Portsmouth. Don't see why not?

    Now what would be really scary is if the message that bounced back from the moon responded with 'hello we're fine up here how's the weather on earth?'

  16. herman Silver badge

    Jupiter

    With an HF receiver and a backyard full of antenna, you can listen to Jupiter at between 15 and 40 MHz.

    1. Kevin McMurtrie Silver badge

      Re: Jupiter

      Presumably in an electrical quiet area. In Silicon Valley, a paperclip in the antenna jack will kick in AGC for just about any radio band.

  17. Avatar of They
    Coat

    I can hear.

    Somewhere literally a few angry conspiracy nut jobs demanding that the moon was never visited and doesn't have mirrors on it. But they don't frequent this place.

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