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#dipole — Public Fediverse posts

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  1. (reposting public, rather than quiet)

    #HamRadio question: What types of #RF cable to buy and from where.

    Low power < 1 watt
    700 M to 5Ghz typical
    DC to 6G sometimes.
    Low loss is nice
    50 Ω

    Specific uses
    1) making #antennas with matching or stubs.
    Indoor and outdoor.
    900 mhz #yagi
    900 mhz folded #dipole

    2) connecting antennas on patio to indoor radio.

    ( 900 mhz, UV / weather resistant outdoor, fire resistant indoor. Possibly flat cable at door. Lightning arr.)

    3) connecting boards together indoors (filters, amps, SDR, etc)

    What I think that requires:

    5 feet of moderately stiff cable for making antennas, #LMR 240/400 or equiv?

    10-20 feet of low-loss outdoor cable (not buried)

    1-2 feet of thin / flat cable to pass around door.

    10-20 feet low-loss indoor cable. Fire resistant?

    10 feet thinner flexible indoor cable to interconnect boards.

    Tools for cutting & crimping. SMA, RPSma, but ideally also other types (TNC, N, maybe BNC, maybe ufl)

  2. Now the new fan #dipole is finally finished. Spacers made from cable ties. Lightweight. Works at 40m, 20m, and 15m. I'm excited. vy73
    #Amateurfunk #hamradio #Antenna

  3. Finally got the $10 ten-meter dipole out of the attic and into the air. I feel like a real ham now lol.

    Interesting that I don't immediately notice a strong directionality difference in my FT8 contacts, though the antenna is nearly perpendicular to the attic direction and the 'inverted v angle' [what's that called?] of the radiators has been small in both instances.

    #10meters #FT8 #dipole #antennas #HamRadio

  4. Mapping the Mozambique Channel

    The Mozambique Channel boasts some of the world’s most turbulent waters, driven by eddies hundreds of kilometers wide. Eddies of this size — known as mesoscale — determine regional flows that influence local biodiversity, sediment mixing, and how plastic pollution moves. To better understand the region, scientists measured a mesoscale dipole from a research vessel.

    Illustration of flows in the Mozambique Channel. The anticyclonic ring in dark blue rotates counterclockwise and consists of largely uniform water (labeled Ring: R1). To the south, in green, a cyclonic eddy rotates in a clockwise sense (labeled Cyclone: C1). This area is chlorophyll-rich and has varying salinity levels. Between the two is a filament of chlorophyll-rich water being drawn from the near-shore region (labeled Filament: F1).

    The dipole consisted of a large anticyclonic ring (shown in dark blue) that rotated counterclockwise and a smaller cyclonic eddy (shown in green) that rotated clockwise. Between these eddies lay a central jet moving up to 130 centimeters per second that drew material out from the shoreline. In the anticyclonic ring, researchers found largely uniform waters with little chlorophyll. The cyclonic eddy, in contrast, was high in chlorophyll and had large variations in salinity. Those smaller-scale variations, they found, helped to drive vertical motions of up to 40 meters per day.

    In situ measurements like these help scientists understand how energy flows through different scales in the ocean and how that energy helps transport nutrients, sediment, and pollution regionally. Such measurements also help us to refine ocean models that enable us to predict this transport and how regions will change as climate patterns shift. (Image credit: ship – A. Lamielle/Wikimedia Commons, eddies – P. Penven et al.; research credit: P. Penven et al.; via Eos)

    #dipole #flowVisualization #fluidDynamics #mesoscale #oceanography #physics #science #turbulence

  5. Very cool to see a lot of people on Mastodon! Here is a little communication on a work:

    New performance "An Eye from Above" premiere in tsonami Festival - Valparaiso - 18 jan 25.

    For over 20 years, the three NOAA satellites have been crossing our sky at over 20,000 km/h, continuously scanning the Earth's clouds and radiant energies.

    An Eye from above is a performance that attempts to receive a live signal from one of these satellites, using an adapted antenna and a radio tuned to 137 MHz. As the satellite rises above our horizon, its signal slowly emerges from the surrounding noise, giving rise to a characteristic pulsation. The antenna acts as a revealer, making perceptible the electrical energy that passes through our bodies and our environment amidst a crowd of other artificial signals.

    Poetry of analog protocols: this pulsation can be decoded into an image. Slowly, line by line, a nephanalysis of the 2000 km that surround us appears. Clouds and infrared radiation from the ground are displayed, offering a shift from our point of view to that of a space object.

    #radioart #soundart #noaa #vhf #137mhz #dipole #sstv

  6. Wago Terminals Make This Ham Radio Dipole Light and Packable - For the amateur radio operator with that on-the-go lifestyle, nothing is more impo... - hackaday.com/2024/12/15/wago-t #amateurradio #radiohacks #antenna #dipole #balun #pota #sota #wago #ham #qrp

  7. Schooling ChatGPT on Antenna Theory Misconceptions - We’re not very far into the AI revolution at this point, but we’re far enough to k... - hackaday.com/2024/11/17/school #common-modecurrent #radiohacks #feedline #amateur #antenna #chatgpt #dipole #radio #coax #ham

  8. `Here we fabricate a single-molecule quantum #sensor at the apex of the metallic tip of a scanning tunnelling microscope..we measure the magnetic and electric dipole fields emanating from a single Fe atom..Our method enables atomic-scale quantum sensing experiments of electric and #magnetic fields on conducting surfaces and may find applications in the sensing of spin-labelled #biomolecules and of spin textures in #quantum #materials`

    nature.com/articles/s41565-024

    #nanosensor #magnetic #dipole

  9. Matchbox Transceiver Pushes the Spy Radio Concept to Its Limits - The Altoids tin has long been the enclosure of choice for those seeking to show of... - hackaday.com/2024/05/09/matchb #amateurradio #transceiver #radiohacks #80-meter #matchbox #sidetone #deadbug #dipole #ne5532 #mixer #morse #ham #cw