RX antenna - 2el end-fire beverage array antenna

This revision is from 2020/11/09 14:18. You can Restore it.

<<- Web page *

The beverage is a long wire antenna installed very close to the ground. The antenna should be longer than 1 wavelength and installed at a height of less than 0,05 wavelength above ground. The beverage is usually terminated in a resistance at the end (opposite the feedpoint). Beverage antennas provide one of the least expensive and most reliable ways to improve DX capabilities on the low frequencies. If you are after improved directivity in the rear of the antenna (improving the DMF), you can put up two Beverages fed as an end-fire phased array.The Beverages you wish to phase together need to be identical (same height and length). In an end-fire Beverage array it is important that the two elements have a similar F/B, as you are going to subtract the signals from both elements. You only get zero if you subtract two identical numbers. It does not matter what the numbers are though. Two Beverages with a 10-dB F/B can produce 30 to 40-dB nulls in an array, just as much as a pair where the individual elements already show 25 dB F/B. (source ON4UN)

Applications

If you are after improved directivity in the rear of the antenna (improving the DMF), you can put up two Beverages fed as an end-fire phased array.The Beverages you wish to phase together need to be identical (same height and length). In an end-fire Beverage array it is important that the two elements have a similar F/B, as you are going to subtract the signals from both elements. You only get zero if you subtract two identical numbers. It does not matter what the numbers are though. Two Beverages with a 10-dB F/B can produce 30 to 40-dB nulls in an array, just as much as a pair where the individual elements already show 25 dB F/B. (source ON4UN)

  • You can compare Single wire and 2el End-Fire array:

Building

  • Please use google and you can find a lot of very nice articles about end-fire arrays.
  • I really recommend:
    • Enhanced F/B Beverages by W8JI
    • Ideas For Enhanced Beverage Antenna Performance by N2NC
    • And the best book called ON4UN's Low Band DXing at dx engineering
      • Chapter 7 and 2.16.3. The End-Fire Beverage Array
  • And some notes:
    • Both antennas must be the same
    • The same height and length
    • Tune terminators to the best flat SWR - should be under 1:1,3 (on 50 ohm feeder)
    • Select null direction if needed from table
    • Calculate phasing line
    • Do not forget on Length L - 2 * L + phasing line must be more than diagonal between feeders !
.
  • Table with Phasing lines vs. element spacing and NULL:

Comparations

Examples