20 pointsby austinallegro2 days ago5 comments
  • hilbert422 hours ago
    Those who've had experience with either transmitting or receiving on the HF band and or lower frequencies (≤30MHz) and who've knowledge of ionospheric propagation just know that short, medium and longwave RF bands are still essential in this digital/cable/satellite era for reasons that when all other communications systems have failed then communications on these frequencies will still be reliable.

    Moreover, in wartime or during some other major catastrophe when technical infrastructure is likely to be impacted or destroyed then establishing and maintaining communications services on these frequencies is easy for reasons that the technology is low-tech and easy to understand—and there's an enormous amount of engineering experience to fall back upon (about 100 years' worth).

    That we even have to raise this discussion is a quintessential example of intergenerational information loss.

    Given their strategic importance, governments should put priority on educating the smartphone/streaming generation that these other modes of electronic communication actually exist and that they may even have to depend upon them.

    I only need to refer to the current debate over retaining AM-band reception in car radios to illustrate the paucity of understanding. That EV manufacturers are pushing for the removal of the AM band in their car radios is proof-positive of how little the current breed of electronics engineers knows about these frequencies let alone their strategic importance.

  • thenthenthen4 hours ago
    Shortwave is magic, I recently made this [0] receiver and it is so much fun (in Europe I received about 10 stations with it on a random wire)

    [0] https://www.qsl.net/pa2ohh/08regrx.htm

  • 2 days ago
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  • euroderf2 days ago
    Having a shortwave (with a decent antenna) is fun. You twiddle the dial and find all kinds of goodies. Pretty soon you'll be scouring teh interwebz for programming schedules.
    • sneak2 days ago
      I have never been able to pick up anything on my SW radio with its integrated antenna.

      What am I doing wrong?

      • thenthenthen4 hours ago
        Check for noise sources (tube lights, solar equipment) as well. A friend had an old thinkpad and the psu brick was so noisy, it was blanking out my radio within 6-10 meters…
      • the-grump2 days ago
        It helps to be high up and to have an unobstructed view.

        An antenna extension (https://www.dxengineering.com/parts/sgn-ant-60) would help.

        Even better would be an active antenna. I have only heard great things about the MLA30+ though I don't own one myself.

        WWCR (4840) has always been the easiest broadcast for me to pick up in the US.

        • sidewndr462 days ago
          Height isn't going to make any real difference for shortwave reception unless you're seriously high up and putting up a very efficient antenna like a dipole. At that point it's kind of moot, as you don't need an efficient antenna anyways to receive shortwave.
          • cf100clunk2 days ago
            Correct about altitude... it is a common misconception that height always improves reception, because it doesn't take into account that radio waves propagate in vastly different ways according to their frequency and wavelength. Thankfully there are organizations like the IRAU and ARLL that have vast amounts of info on what does and doesn't work in a wide variety of locations, bands, and altitudes:

            https://en.wikipedia.org/wiki/List_of_amateur_radio_organiza...

          • euroderf2 days ago
            I've read (but not tried) that what works is a verrry loooong wire strung up like between trees or in a barn.
            • cf100clunk2 days ago
              Regarding simply stringing long wire, if you have a huge, flat land area and don't mind overhead wires, erect a rhombic antenna on dedicated poles for extremely high gain but with a few downsides worth reading about, such as the sheer size needed for shortwave. Don't string wires between trees as they are guaranteed to snap in the wind.

              https://en.wikipedia.org/wiki/Rhombic_antenna

              • sidewndr462 days ago
                To my knowledge there is basically one person doing non-commercial work with rhombics in north america: https://www.k0uo.com/

                The same guy also owns an airport from what I recall.

            • sidewndr462 days ago
              It's not a bad choice, but the tiny tecsun radio I have has a telescopic antenna that is about 3 ft long when extended. It receives shortwave very well.

              If there is some distant broadcast (maybe overseas) that you want to receive you can definitely build a very efficient antenna system for that broadcaster's frequency. Be prepared to shell out well over $10,000 for this.

            • UncleEntity2 days ago
              I tried that with my buddy's shortwave while on guard duty in Iraq and fried the thing due to atmospheric electrostatic energy discharge (or it's actual scientific name), needless to say he was less than happy with me. First clue probably should have been the visible sparks coming off the antenna wire. Second clue should have been I was sitting in a truck insulated from the ground. Yep, he definitely should have known better.
              • sidewndr462 days ago
                its more likely that the wire coupled in a very large amount of RF power from a transmitter that was at the base, damaging the unit. I obviously don't know your units deployment equipment, but the transmitter at the base is often greater than 100 watts of output
                • UncleEntity2 days ago
                  Could be, I always just assumed it was from the high prevalence of static electricity in the desert. When I lived in Phoenix I would always touch the back of my hand to anything metal (like doorknobs) before touching it with my fingers because I've been shocked way too many times.
          • the-grump2 days ago
            It helps as far as avoiding obstructions is concerned. I can barely pick up anything in my porch. On my ceiling it's many times better.