back to article Hey, turn down that radio, it's alien season and we're hunting aliens

Some clever folks have started an experiment that will hunt for signs of alien civilisations using the Murchison Widefield Array – a low frequency radio telescope in western Australia. Eggheads at Curtin University, Down Under, and the Istituto Nazionale di Astrofisica in Italy, have published a paper outlining the experiment …

  1. Mage Silver badge

    Won't work

    See Cosmic background noise vs Frequency (rises sharply as frequency reduced), Shannon's Law (Information) and Inverse Square Law. Also dish gain is related to the cube of frequency, thus 1/10th frequency gives 1/1000th gain on same size dish.

    Only spectroscopic analysis is likely to give results, starlight affected by planetary transits. Radio is good only to a few light years or a bit more if someone is pointing THEIR massive array with Gigawatts of power at us.

    1. Destroy All Monsters Silver badge

      Re: Won't work

      SETI Institute waited to be told by some commentard.

      So done!

    2. Gotno iShit Wantno iShit

      Re: Won't work

      Yes, that thing you thought of in a few moments reading a page on the internet, the SETI boffins won't have thought of that for sure.

    3. JeffyPoooh

      Re: Won't work

      Once upon a time, an edition of a radio communications magazine published advice to try the technically challenging EME (Moonbounce) communications in the 160m band (1.8 MHz).

      "Fewer Wavelengths to the Moon" ...

      ...was the logical basis, as per the well known 'Pathloss Equation' (the one with 32.45 dB, etc.). Lower frequency = less pathloss.

      Yep. It was the April edition.

    4. Howard Long

      Re: Won't work

      Check your maths. Swings and roundabouts on antennas and path loss vs frequency.

      Gain for a given antenna aperture area is proportional to frequency squared, not cubed. Note this is area, not diameter.

      However pathloss over a given distance is proportional to frequency.

      The reason to go up in frequency traditionally has been to avoid noise, terrestrial as well as galactic.

      1. JeffyPoooh

        Re: Won't work

        HL, it's not exactly "swings and roundabouts" if it's square vs. proportional.

        Just sayin'. :-)

        1. Howard Long

          Re: Won't work

          Jeffy poohs, It is swings and roundabouts if you include path loss, as you'll see I specificallly mentioned.

          However as I also mentioned, going down in frequency also increases the ambient noise floor.

          But then making very low noise receivers is easier at lower frequencies.

          But then your beam width increases with lower frequency, so more noise.

          But then increased beam width means more simultaneous coverage.

          But then wider coverage area means more difficult to pinpoint the source.

          Lots of swings and roundabouts, but my main point was around the size of the antenna aperture combined with path loss, and all other things being equal means that the change in gain due to frequency is offset by the change in path loss. It's all part of an RF link budget calculation.

          Just sayin' ;-)

    5. tony2heads

      Re: Won't work - Dish gain

      Dish gain only really helps you if you know where to look. The advantage of arrays like the MWA is that they can make multiple phased-arrays, scanning in multiple directions simultaneously.

    6. Anonymous Coward
      Anonymous Coward

      Re: Won't work

      OP - NM the trolls that don't know anything there isn't an app for, those of us involved in radio know how valid your concerns are.

      Fortunately, noise cancellation is somewhat an easy process with differential samples. Doesn't take care of everything, but does make the S/N ratio go on par with the noise temp of the LNA.... THAT is still a serious problem even with cryogenics at ground level.

      1. JeffyPoooh

        Re: Won't work

        GG "...make the S/N ratio go on par with the noise temp of the LNA..."

        At HF and below, the noise is set by the external environment. At UHF and above, it's pretty much down to the NF of the LNA. At VHF (e.g. 100 MHz), it's the area of transition. As LNAs have gotten better over the years, the 'crossover' has drifted upwards. These days, at VHF (the subject here), it isn't all that difficult to get into the external noise.

        Even nearly 30 years ago, met a guy that was into the external noise at UHF. The Sun passing across his 20-foot dish caused a big noise peak. NF less than a half dB. A long time ago.

        ~40 years in Comms. (Geesh, I'm closer to death than that.)


        __... ...__

  2. Anonymous Coward
    Anonymous Coward


    can't SETI just trot over to Edwards Air Force Base, and ask someone there if they're wasting their time?

    1. Rich 11

      Re: FFS

      "I can neither confirm nor deny that you are wasting your time, sir."

    2. Anonymous Coward Silver badge

      Re: FFS

      Yes, you are wasting your time, by coming here and asking me... among other reasons.

  3. Roger Kynaston

    I for one

    Welcome our low frequency overlords.

    had to be done.

    1. Uffish

      Re: I for one

      And I for one would like to ask them, or one of their boffin friends, why they call it the Low Frequency Array when it operates in the VHF band (Very High Frequency).

      1. Roger Kynaston

        Re: I for one take 2

        Well looking at frequencies in the MHz range as opposed to the GHz range is I suppose relatively long wavelength.

        I am not very good with radio propagation but very long wavelength (on the order of KHz) bounces off the ionoshere so I presume that just as SW radio can travel round the world any incoming SW would bounce back out into space.

        I am going to fit the boat with an HF with a pactor modem set at some point so will have to learn more about all that sort of stuff.

        Beer because it is nearly time.

        1. JeffyPoooh

          Re: I for one take 2


          First tidbit: kHz, not KHz.

          :-) !!!

        2. This post has been deleted by its author

          1. JeffyPoooh

            Re: I for one take 2

            TE "...the MUF is quite low..."

            Yes, it can be.

            1. Graham Dawson Silver badge

              @jeffypoooh Re: I for one take 2

              Comment quality around these parts had taken a real dive...

              1. Graham Dawson Silver badge

                Re: @jeffypoooh I for one take 2

                A downvote? Seriously? Does context mean nothing to you people?

                1. JeffyPoooh

                  Re: @jeffypoooh I for one take 2

                  GD "...context mean nothing to you people?"

                  I appreciate your sense of humour.



                  It cracked me right up.

              2. JeffyPoooh

                Re: @jeffypoooh I for one take 2

                GD "...a real dive..."

                I see what you did there. Have an upvote.

            2. Yer Mother You Will

              Re: I for one take 2

              I wish contesting on HF could be banned. There is no need for this noise.

        3. Uffish

          Re: Low, very high, frequencies

          The radioastronomy boffins say that useful results from terrestrial observations have been obtained at frequencies from 2 MHz to 1 000 GHz and above.

          All I suggested is that they should use the appropriate ITU band designation (VHF) instead of writing the first thing that came into their heads.

          After all it is the ITU that coordinates the world-wide protection from terrestrial interference for the radioastronomy frequencies.

        4. This post has been deleted by its author

        5. Yer Mother You Will

          Re: I for one take 2

          I will suggest you study radio propagation before buying any HF transceiver. It's like telling a 5-year-old you have bought him his very own motor vehicle. Comprehension of ALL aspects of radio propagation and the F1-F2-E-layer and D-layer should be studied and fully absorbed before opening the box. g6ypk QTHR and

      2. Francis Boyle Silver badge

        Re: I for one

        "And I for one would like to ask them, or one of their boffin friends, why they call it the Low Frequency Array when it operates in the VHF band (Very High Frequency)."

        Astronomers have a different sense of scale. Hence the local group (of galaxies).

      3. Anonymous Coward
        Anonymous Coward

        Re: I for one

        VHF is called "low frequency" due to a historical oddity. In the early days of radio the frequencies used were quite low. The technology level required for radio goes up with frequency, so the lowest freaks were all they could manage. That was "radio" as far as anyone was concerned.

        Then as tech improved they were able to shorten wavelengths down to where reasonable antenna lengths became possible, letting the public in on the action generally. They had to call the new frequencies something, and the 'standard' frequencies were actually extremely low, so they had nowhere to go but up. Thus we got high frequency (HF), very high frequency (VHF), ultra high frequency (UHF) and so forth.

        So what was then considered high is now considered low, but no one ever bothered to change the terminology.

  4. JeffyPoooh

    Certainly there's no intelligent life between 103 and 108 MHz

    That's the top end of the FM Broadcast band. Not much signs of intelligent life there. LOL *

    Above 108 MHz, you'll soon be into VHF Navigational Beacons and Aircraft pilots chattering away like magpies.

    As already noted, "low frequency" is a defined frequency range, 30 to 300 kHz. One will find intelligent life within that band, specifically BBC Radio 4 'Longwave' on 198 kHz.

    (* Acknowledge in advance that BBC 4 is also on 103.5-104.9 MHz. The joke is worth the discrepancy.)

    1. Zippy's Sausage Factory

      Re: Certainly there's no intelligent life between 103 and 108 MHz

      BBC Radio 4 is also available on long wave, at lower frequency, with more cricket. Some would argue that this increases the IQ of the station considerably...

      1. JeffyPoooh

        Re: Certainly there's no intelligent life between 103 and 108 MHz

        Yes, 198 kHz. As was mentioned. :-)

  5. Brian Allan 1

    If those aliens are smart...

    Those aliens have probably already looked at homo sapiens and decided they want ABSOLUTELY nothing to do with us! They'll keep really quiet!!

    1. Anonymous Coward

      Re: If those aliens are smart...

      The aliens wrote us off after their own SETI effort picked up "Rick & Morty's Drivetime Top 40 Fantasy!! Brought to You by the Good People at Mattress Mart."

  6. John Brown (no body) Silver badge

    Murchison Widefield Array

    Is that the same guy with a Mote in his eye?

  7. Mark Simon

    What do they expect to find?

    Some of the targets are billions of light years away. That means they’re looking for signals that are billions of years old. Than means they’re looking for a civilization that was transmitting billions of years ago. Which means that they’re looking for a civilization which is billions of years ahead of us.

    Here’s the funny part. Suppose we’re even 100 years too early, before this civilization has developed the means to send a signal in the first place. Wouldn’t that be a bummer.

    On the other hand, suppose they actually get a signal. What are the chances that they’re still around billions of years later, or still care?

  8. Yer Mother You Will

    The hydrogen line is chosen because the radio noise is far lower at those frequencies, this, listening for ultra-weak signals become less problematic. Even to, on has to cryogenically perform front end miracles. "The Water Hole"? Never heard of this before, must be made up journalistic claptrap.

    Nothing will be found. I emailed the extra terrestrials and asked them to keep quiet.

    1. JeffyPoooh

      "The Water Hole"? Never heard it, must be journalistic claptrap.

      Wiki says, "The term was coined by Bernard Oliver in 1971."

      For what it's worth, I have heard of the term (in this context) innumerable times.

      And I don't even pay all that much attention to SETI. 'Passing interest'


  9. TheDillinquent

    low frequency radio waves?

    Isn't 103 to 133MHz in the VHF band?

    Just saying...

  10. Conundrum1885


    Also worth mentioning, thunderstorms can emit very strange signals especially "EM bursts" linked to ball lightning.

    Some folks on the amateur bands claim that "whistlers" are actually BL confined to a storm or the almost legendary "dark" variety which has not yet become visible.

    These show up on IR scanners sometimes and have been linked to car alarms sounding just after (8-90 seconds) a storm as has been observed here not once but twice.

    For more information see my research.

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