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  2. 80-meter band - Wikipedia

    en.wikipedia.org/wiki/80-meter_band

    The nominal "80 meter" band begins at 3.5 MHz (85.7 m wavelength) and goes up to 4.0 MHz (74.9 m wavelength).The upper part of the band, mostly used for voice, is often referred to as 75 meters, since in Region 2, the wavelengths in that section are between 80–75 meters (adjacent to or overlapping a shortwave broadcast band called by the same name: "75 m").

  3. Amateur radio frequency allocations - Wikipedia

    en.wikipedia.org/wiki/Amateur_radio_frequency...

    The nominal "17 m" band actually covers 16.6–16.5 m. The nominal "15 m" band actually ranges from 14.28–13.98 m. By common sense, the "15 m" band ought to be called "14 m", but that name has been in longtime use for a shortwave broadcast band. 80 metres or 80 / 75 meters – 3 500–4 000 kHz – 85.65–74.95 m actual

  4. Amateur radio direction finding - Wikipedia

    en.wikipedia.org/wiki/Amateur_radio_direction...

    ARDF events use radio frequencies on either the 2-meter or 80-meter amateur radio bands. These two bands were chosen because of their universal availability to amateur radio licensees in all countries. Each band requires different radio equipment for transmission and reception, and requires

  5. Loop antenna - Wikipedia

    en.wikipedia.org/wiki/Loop_antenna

    Loop antenna, receiver, and accessories used in amateur radio direction finding at 80-meter (260-foot) wavelength (3.5 MHz). As long as the loop perimeter is kept below about ⁠ 1 / 4 ⁠ wave, the directional response of small loop antennas includes a sharp null in the direction normal to the plane of the loop, so small loops are favored as ...

  6. T2FD antenna - Wikipedia

    en.wikipedia.org/wiki/T2FD_antenna

    A 20-meter-long T²FD antenna, covering the 5-30 MHz band. The T ilted T erminated F olded D ipole ( T²FD , T2FD , or TTFD ) or B alanced T ermination, F olded D ipole ( BTFD ) - also known as W3HH antenna - is a general-purpose shortwave antenna developed in the late 1940s by the United States Navy .

  7. Skywave - Wikipedia

    en.wikipedia.org/wiki/Skywave

    On October 10, the Third National Radio Conference made three shortwave bands available to U.S. amateurs [8] at 80 meters (3.75 MHz), 40 meters (7 MHz) and 20 meters (14 MHz). These were allocated worldwide, while the 10-meter band (28 MHz) was created by the Washington International Radiotelegraph Conference [9] on 25 November 1927

  8. FM broadcast band - Wikipedia

    en.wikipedia.org/wiki/FM_broadcast_band

    The 4-meter band (70–70.5 MHz) amateur radio allocation used in many European countries is entirely within the OIRT FM band. Operators on this band and the 6-meter band (50–54 MHz) use the presence of broadcast stations as an indication that there is an "opening" into Eastern Europe or Russia. This can be a mixed blessing because the 4 ...

  9. Inverted vee antenna - Wikipedia

    en.wikipedia.org/wiki/Inverted_vee_antenna

    For example, a dipole antenna for the 80 meter band requires a ground length of about 140 feet (43 m) from end to end. An inverted vee with a 40-foot (12 m) apex elevation requires only 115 feet (35 m). For radio amateurs living on small parcels of property, such savings can make it possible to use the lower frequency amateur bands.