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K9AY Loop Arrays for Low Band Contesting
Richard C. Jaeger, K4IQJ
May 16, 2013
Dayton 2013
INTRODUCTION
K4IQJ Interests /Background Introduction
RDF Definition Basic K9AY Loop Pair
K9AY Array Comparisons 2-3-4 Element Arrays
4 Element Array Design & Simulation Array Implementation
Discussion / Observations
Dayton 2013
Dayton 2013
INTRODUCTION
Interests Low Band Contesting
NAQP CW ARRL & CQWW 160 Contests Stew Perry CW Sprints (Alabama Low Power Record)
DXing Top of the Honor Roll, Need P5 on CW, CQ WAZ 300+ Countries Worked on 80 – 10 255 Countries Worked on 160M
Dayton 2013
Dayton 2013
INTRODUCTION
Need to Hear Well on 160/80 M Big Advantage in NAQP and DX Contests
Loops Seem Most Effective Receiving Antennas in My Locations (Poor Ground Conditions)
Discussed 2-Element Arrays - 2012 Presented 3-Element End-fire Array – 2011 Latest Effort - 4-Element Array (15.1dB RDF)
100 foot spacing (330’ total length) RDF greater than individual beverages
Dayton 2013
Dayton 2013
BACKGROUNDRDF: Receiving Directivity Factor
Design Goal Here: Maximize RDF
RDFdB = Gfor(dB) - Gavg(dB)
Noise generally comes from all directions RDF compares the main antenna lobe gain to
the average gain over the whole hemisphere of the antenna
Attributed to W8JI
Dayton 2013
Dayton 2013
BACKGROUND Reference Antenna - Short Vertical (20’)
RDFdB = Gfor(dB) - Gavg(dB)
RDFdB = Gfor(dB) - Gavg(dB)
RDFdB = 1.0 – (-3.9) = 4.9 dB
Dayton 2013
Dayton 2013
BACKGROUNDBasic K9AY Loop
• 85’ Triangular Loop• 25’ High, 30’ Wide • Resistive Termination• Directional Antenna
- Easily switched in 2 directions
- 4 directions with an orthogonal pair of loops
• 9:1 Matching Transformer to Coax
Gary Breed, “The K9AY terminated loop – A compact, directional receiving antenna,” QST, vol. 81, no. 9, pp. 43-46, September 1997.
Signal Arrival
RDFdB = Gfor(dB) - Gavg(dB)
RDF = (-24.7) - (-32.1) = 7.4 dB
Dayton 2013
LOOP ARRAYSMulti-Element Endfire Arrays
“Lossy” Antennas Resistive termination Little or no mutual coupling
Loops are Broadband – Usable over a Wide Frequency Range
Array Output Decreases as Number of Elements Increases (-24 dBi) (-40 dBi)
Luis, IV3PRK: “K9AY Loops Always Seem to Work”
Dayton 2013
Dayton 2013
TWO-ELEMENT END-FIRE ARRAY80’ Spacing – 200o phasing
Element 2 Phasing (-200o)
• Two-Element Array- Equal amplitudes- Single phasing line- Rear element lags front
element by > 180o
• Gain: -25.6 dBi
• RDF: 10.5 dB (+3 dB)
• Beam Width: 96o
• W/C F/B: 16.6 dB
• Take Off Angle: 25o
Dayton 2013
Dayton 2013
TWO-ELEMENT END-FIRE ARRAYSimulation Results - 160 M
RDF 10.7 dBGain -26.4 dBiF/B 15.2 dB
Note: RDF Falls as Gain Drops RDF = 7.5 dB at 45o points
Dayton 2013
LOOP ARRAYS3 & 4 Element Endfire Arrays
Binomial Endfire Array Nominal Amplitudes 3 EL (1-2-1) 4 EL (1-3-3-1)
RDF Optimization (1-2-1) (1-1.84-1) (1-3-3-1) (1-2.4-2.4-1)
Dayton 2013
LOOP ARRAYS3 & 4 Element Endfire Arrays
3 Element Array 80’ Spacing Gain: -29.5 dBi (20o) Beamwidth: 66o
RDF: 12.5 dB 4 Element Array
100’ Spacing (Sensitivity) Gain: -35.6 dBi (16o) Beamwidth: 49o
RDF: 15.1 dB
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K9AY ARRAYSRDF Comparisons
(1-2.4-2.4-1) (0.42-1-1-0.42)
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ARRAY IMPLEMENTATIONCross-Fire Feed (W8JI)
Dayton 2013
From Low Band DXing [3]
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ARRAY IMPLEMENTATION0o Hybrid Combiners
Z
Z
From Low Band DXing [3]
Dayton 2013
Dayton 2013
4 EL ARRAY IMPLEMENTATIONAmplifiergs & Coax Phasing Lines
Desired Gains (Hi-Z Plus-6 Amplifiers) Elements 1 and 4: 0.42 or -7.5 dB
Adjust Output Resistance Elements 2 and 3: 1.00 or 0 dB
Output Resistance at 75 W
Desired Phase Delays on 160 M Element 1: 0o
Element 2: 190o = 180o + 10o Element 3: 380o = 360o + 20o 20o
Element 4: 570o = 540o + 30o 180o + 30o
Dayton 2013
Dayton 2013
4 EL ARRAY IMPLEMENTATIONAmplifier & Coax Phasing Lines
Desired Phase Delays on 160 M Element 1: 0o
Element 2: 190o = 180o + 10o Element 3: 380o = 360o + 20o 20o
Element 4: 570o = 540o + 30o 360o + 180o + 30o
Combiner: DX Engineering 4 Square Controller Uses Three Separate Delay Lines Two Inputs Go Through 180o Phase Inversion Transformer Two Inputs Have 0o Shift Within the Controller Antennas Reversed With External Switching
Dayton 2013
Dayton 2013
ARRAY IMPLEMENTATIONCoax Phasing Lines Network or Antenna Analyzer
Measure The Resonant Frequency Or Fault Of Open-circuited Line Calculate Phase By Frequency Scaling
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FOUR-ELEMENT ARRAY Simulation Results – 160 M
Dayton 2013
Spacing: 100 FtAmplitudes: 0.42-1-1-0.42Crossfire Phasing: 0, -190o, -380o, -570o
FOUR-ELEMENT ARRAY Simulation Results (Cont.)
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FOUR-ELEMENT ARRAY Simulation Results - 80 M
Dayton 2013
Spacing: 100 Feet Between LoopsAmplitudes: 0.42-1-1-0.42Crossfire Phasing: 0, -200o, -400o, -600o
FOUR-ELEMENT ARRAY Simulation Results - 80 M
Dayton 2013
Dayton 2013
ARRAY IMPLEMENTATIONLoop Termination and Switching
DPDT Relay
Dayton 2013
560 W Termination
ARRAY IMPLEMENTATIONLoop Design and Array Control
Loop Support, Direction Control Box, Hi-Z Amplifier
• Loops as Identical as Possible
• High Impedance Amplifiers
- (Hi-Z Plus 6)
• ac Coupled (loop dc short)
• Single 510-W Termination
• Flooded RG-6 Coax
• DPDT Relay Switching
• A 3’ Ground Stake at Loop Center
• Four 20’ Radials Under Each Loop (45o relative to loop)
• Fiberglass Poles (MaxGain Systems)
• Aluminum Can Also be UsedHi-Z Amplifier Direction Control
Dayton 2013
4 EL ARRAY IMPLEMENTATIONLoop & Controller
Individual Loop Controller During Installation
Dayton 2013
Dayton 2013
4 EL ARRAY IMPLEMENTATIONLoop Alignment!
N/S Array E/W ArrayFiberglass Support Poles (Max-Gain Systems)Control Cables and Coax in PVC on GroundArray Looking NE Array Looking SW
Dayton 2013
Dayton 2013
ARRAY IMPLEMENTATIONSystem Design
Combiner – Spare DXE 4 Square Controller Hi-Z Plus 6 Amplifiers
500 antennas connected directly to amplifier inputs Must Switch Loop Terminations with Controller
Direction Simple Switching of Inputs to Controller to
Reverse Array “Common-mode” Chokes (The Wireman)
Dayton 2013
ARRAY IMPLEMENTATIONSystem Design
Delay 3Delay 2
Delay 1
Dayton 2013
Verticals are Easier to Install No Direction switching
Vertical Footprint Somewhat Smaller Extra 30-40 ft Needed for Loops
Loops Appear More Independent of Ground Conditions
Simulation Gives Loops a Slight Advantage in RDF (0.5-0.6 dB)
Simulation Gives Verticals a Large Output Advantage (Not realized!)
MULTIELEMENT ARRAY COMPARISONS
Dayton 2013
K9AY LOOPS & SHORT VERTICALSComparison of Simulation Results
Comparison - K9AY Loops (85’) and Verticals (26.5’)
# of Elements
RDF (dB) Output (dBi)
Loops Verticals Loops Verticals
1 7.4 4.9 -23.6 5.8
2 10.5 9.8 -25.6 5.8
3 13.1 12.4 -29.2 7.9
4 15.1 14.7 -35.6 9.6
*Note: The actual output of the verticals is much lower when connected to high impedance amplifiers
Dayton 2013
K9AY LOOPS & SHORT VERTICALSExperiment Underway
• Interlaced 3- Element Arrays NE/SW Array
• K9AY Loops and 26.5’ Verticals
• Aluminum Loop Supports form• Vertical Array
• Single Switch between Arrays
• In Operation for 6 Months Through this Year’s 160 M Season
Dayton 2013
Simulation Aluminum Supports Do Not Disturb K9AY Loops Loops Must be Floated to Avoid Vertical Array Pattern
Distortion Hearing of Both Arrays is Similar
Loop Array Almost Always has a Small but Perceptibly Better SNR (Ears can hear the 0.5 dB difference).
F/B of Loop Array is Better Output of Loop Array is Actually Higher than that of
Vertical Array
K9AY LOOPS & SHORT VERTICALSQualitative Results Thus Far
Dayton 2013
Dayton 2013
SUMMARY
I Hear Well on the Low Bands Big Advantage in NAQP and DX Contests
The Arrays Act Similar to Yagis Often Hear Signals Well that are Unreadable on
My Transmit Verticals Signals Pop Out of the Noise Gain and F/B are Apparent Unfortunately Not Rotatable
Frequently Usable on All Bands (Although with Unknown Patterns)
Dayton 2013
Dayton 2013
REFERENCES1. Gary Breed, “The K9AY terminated loop – A compact, directional receiving antenna,”
QST, vol. 81, no. 9, pp. 43-46, September 1997.
2. Gary Breed, K9AY, "Arrays of K9AY Loops: "Medium-sized" low band RX antenna solutions," Sept. 15, 2007. http://www.aytechnologies.com
3. John Devoldere, ON4UN's Low-Band DXing, Fourth & Fifth Editions, ARRL, Newington, CT: 2005 & 2011.
4. Dallas Lankford, http://groups.yahoo.com/group/thedallasfiles
5. http://www.fcc.gov/mb/audio/m3/index.html
6. Hi-Z Antennas 4-Square, http://www.hizantennas.com
7. DX Engineering 4-Square, http://www.dxengineering.com
8. Max-Gain Systems, http://www.mgs4u.com
9. The Wireman, http://www.thewireman.com
10. Richard C. Jaeger, K4IQJ “Multi-Element End-fire Arrays of K9AY Loops,” expanded version of 2011 Dayton presentation, May 15, 2011, available at http://www.k4iqj.com_. Also 2012 Presentation on 2 Element Arrays.
11. Richard C. Jaeger, “Multi-Element End-fire Arrays of K9AY Loops,” QEX, pp. 22-31, Jan./Feb. 2013.
Dayton 2013
