RECEIVING ANTENNAS

DIRECTIVE ANTENNAS FOR SMALL LOTS

HIGHER PERFORMANCE ANTENNAS FOR LARGER LOTS

VERY PERFORMANCE ANTENNAS FOR MULTI ACRE LOTS

 Why Receiving Antennas?

  • Much better performance especially on 80 and 160 meters and multi-acre lots
  • Much better performance than transmitting antennas, especially on 160 and 80 meters
  • Greatly reduced footprint
  • Reduced height
  • Reduced mutual coupling between elements
  • Greatly receiving antenna design
  • Greatly reduced need for high efficiency
  • Greatly reduced cost
  • Greatly reduced height
  • Greatly reduced mutual coupling between elements
  • Combining two antennas with a variable phase controller
  • Diversity reception with dual phase locked receivers (i.e. K3)

Receiving Directivity Factor (RDF)

  • RDF is an accurate, proven measure of receiving antenna performance
  • Forward gain at the desired azimuth and elevation angle compared to average gain over the entire hemisphere
  • Nearby antennas and power lines degrade actual RDF, especially high RDFs
  • 4 dB: Small diameter loop
  • 5 dB: A single vertical antenna (1/4 wavelength vertical and short verticals)
  • 4 - 6 dB: 250 - 400 foot Beverages and Beverage on Ground (BOG)
  • 6 - 8 dB: Array of small loops (flag, pennant, ewe, K9AY, shared apex loop array)
  • 9 dB:   Two element array of short verticals or a triangle array (65 foot spacing)
  • 10 dB: 500 - 600 foot Beverage
  • 11 dB: wo close spaced 500 - 600 ft Beverages staggered 65 feet
  • 12 dB:800-900 foot Beverage
  • 12 dB:4-square array of short verticals only 65 feet on a side  (1/10 acre)
  • 13-14 dB:  4 short verticals or a steerable 8-circle array of short verticals (1 - 3 acres)
  • 14 dB 2 broadside, staggered 800-900 ft Beverages separated 350 ft (8 acres or more)
  • 14-16 dB:  3 broadside 800-900 ft Beverages and arrays of 8 short verticals (5 - 20 acres)

Popular Receiving Antenna

Loops

  • Small diameter loop (High Q Factor)
  • Fixed unidirectional loop (flag, pennant, ewe, K9AY)
  • Mechanically rotatable unidirectional loop (rotatable flag)
  • Electrically steerable compact array of loops (K9AY, Shared Apex Loop Array

Beverages

  • Single wire Beverage
  • Beverage on ground (BOG)
  • Two wire bi-directional Beverage
  • Two close spaced Beverages, staggered 65 feet
  • Phased broadside Beverages spaced 350 feet
  • Phased broadside staggered Beverages (350 feet broadside, staggered 65 feet

Arrays of short verticals (2 elements to 8 elements or more

  • Active  high impedance verticals with amplifiers at the base of each vertical
  • Passive low impedance verticals with radials and umbrella wires

Small Diameter Loop (Q factor needs a tuning capacitor for multi-band use

  • Inexpensive and very easy to build and use
  • 24 - 36 inch diameter
  • Bidirectional 160 degree 3 dB beam width
  • 4 dB RDF

Electrically Steerable Loop Arrays

  • Two K9AY Loops
  • Switchable in four directions
  • Footprint is only 25x25 feet and 25 feet tall
  • 120 degree 3 dB beam width
  • 7 dB RDF
  • Shared Apex Loop Array
  • 8 dB RDF
  • Loop antennas produce very low signal levels
  • High gain, low noise, high dynamic range preamplifier
  • Switchable in eight directions
  • Footprint is only 50x50 feet and 25 feet tall
  • 75 degree 3 dB beam width
  • Requires careful attention to isolating stray pickup from:

Coaxial feed line

Control cable

Bury cables about 12 inches deep for best null depth

  • Two K9AY Loops
  • 25x25 foot square footprint
  • Switchable in four directions
  • 120 degree 3 dB beam width
  • 7 dB RDF

Shared Apex Loop Array (Array Solutions AS-SAL-30)

  • 50x50 foot square footprint
  • Switchable in eight directions
  • 75 degree 3 dB beam width
  • 8 dB RDF

Single Wire Beverage

A very simple and inexpensive antenna

  • 250 - 400 feet long    4 - 6 dB RDF    100 degree beam width
  • 500 - 700 feet long    10 dB RDF       70 degree beam width
  • 800-900 feet long      12 dB RDF       60 degree beam width
  • Longer than 900 feet often results in degraded performance.

A beverage on the ground

  • A good choice when stealth is important about 220 feet long
  • Longer lengths often degrade performance 70 -100 degree beam width 6 - 8 dB RDF
  • An example of one can be viewed at: http://www.n4dj.com/Beverage.html

A two element Bidirectional Beverage

  • Two directions with full Beverage directivety simultaneous dual reception or switched.
  • This requires two complete antennas phased. Why not just run one Beverage un-terminated.

Staggered Pair of Beverages

  • Significantly enhanced front-to-back ratio compared to a single wire Beverage
  • The deep rear null can be steered by a variable phase combiner
  • 11 dB RDF for 500-600 foot Beverages
  • Diagrams of this system can be viewed at: http://www.w8ji.com/echelon-log_beverages.htm

Phased Short Verticals

  • Two or more high impedance 24 foot verticals
  • No radials
  • No umbrella wires
  • As little as 65 foot element spacing
  • Closer spacing is possible with precise phase and amplitude alignment
  • Needs a high gain amplifier at the feed point of each vertical
  • Requires careful attention to all construction details
  • Switchable in multiple directions
  • Cannot be installed within ten feet of nearby objects
  • Trees
  • Any other conductive or partially conductive structure

http://www.hizantennas.com

Electrically Steerable 4-Square Vertical Array

  • Four high impedance 24 foot verticals
  • No umbrella wires, no radials
  • 80x80 foot square footprint
  • Requires a high gain amplifier at the base of each vertical, switchable in four directions
  • 100 degree 3 dB beam width
  • 12 dB RDF in a small space

Phased Short Verticals

Two or more low impedance 25 foot verticals

  • Requires eight 70 foot radials per vertical
  • Or sixteen 35 foot radials
  • Laid on the ground or shallow buried
  • Requires four 25 foot umbrella wires per vertical
  • Or four 35 foot verticals with no umbrella wires
  • As little as 65 foot element spacing
  • Closer spacing is impractical for optimum performance
  • No amplifiers are needed at the base of each vertical
  • Switchable in multiple directions
  • Tolerant of nearby objects
  • Easy to home-brew your own antenna
  • Large arrays are very tolerant of moderate amplitude and phase errors

Electrically Steerable 4-Square Vertical Array

  • Four low impedance 25 foot umbrella verticals
  • Four 25 foot umbrella wires per vertical
  • Eight 70 foot or sixteen 35 foot radials per vertical
  • 65x65 foot square footprint
  • Switchable in four directions
  • Easy and inexpensive to build
  • 100 degree 3 dB beam width
  • 12 dB RDF in a small space
  • This system can be viewed at:
  • www.iv3prk.it/user/image/site2-rxant.prk_4-square_1.pdf

Electrically Steerable 8-Circle Vertical Array

  • Eight low impedance 25 foot umbrella verticals
  • Four 25 foot umbrella wires per vertical
  • Eight 70 foot or sixteen 35 foot radials per vertical
  • 300 - 350 foot array diameter,
  • Switchable in eight directions
  • Easy and inexpensive to build
  • 45 degree 3 dB beam width similar to a 5 element Yagi
  • 14 dB RDF

Electrically Steerable 8-Circle Vertical Array

  • Eight low impedance 25 foot umbrella verticals
  • Four 25 foot umbrella wires per vertical
  • Eight 70 foot or sixteen 35 foot radials per vertical
  • 300 - 350 foot array diameter
  • Switchable in eight directions
  • Easy and inexpensive to build
  • 45 degree 3 dB beam width similar to a 5 element Yagi
  • 13 dB RDF

The construction details:   http://www.w5zn.org

Reference: Frank Donovan W3LPL Contest University

  • All above vertical arrays are of mono band type optimized for the 160 meter band they can be made modified for multi-band use but the performance will be greatly degraded, it is best to use a separate array for other bands.
  • A good alternative is to use a three to five hundred foot beverage a as they work very well on 30, 40, 80, and 160 meters. I have used mine that is just shy of 400 feet long on 17, 20 and 15 meters with good results.  Jon NJ3I