K9AY Loop Arrays for Low Band Contesting Richard C. Jaeger, K4IQJ May 16, 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 DXing 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

BACKGROUND RDF: 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 = 1.0 – (-3.9) = 4.9 dB RDFdB = Gfor(dB) - Gavg(dB) Dayton 2013 Dayton 2013

BACKGROUND Basic 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 Signal Arrival RDFdB = Gfor(dB) - Gavg(dB) RDF = (-24.7) - (-32.1) = 7.4 dB Gary Breed, “The K9AY terminated loop – A compact, directional receiving antenna,” QST, vol. 81, no. 9, pp. 43-46, September 1997. Dayton 2013 Dayton 2013

LOOP ARRAYS Multi-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

TWO-ELEMENT END-FIRE ARRAY 80’ Spacing – 200o phasing 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 Element 2 Phasing (-200o) Dayton 2013 Dayton 2013

TWO-ELEMENT END-FIRE ARRAY Simulation Results - 160 M RDF 10.7 dB Gain -26.4 dBi F/B 15.2 dB Note: RDF Falls as Gain Drops RDF = 7.5 dB at 45o points Dayton 2013 Dayton 2013

LOOP ARRAYS 3 & 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 ARRAYS 3 & 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 Dayton 2013

K9AY ARRAYS RDF Comparisons (1-2.4-2.4-1)  (0.42-1-1-0.42) Dayton 2013

ARRAY IMPLEMENTATION Cross-Fire Feed (W8JI) From Low Band DXing [3] Dayton 2013 Dayton 2013

ARRAY IMPLEMENTATION 0o Hybrid Combiners Z From Low Band DXing [3] Dayton 2013

4 EL ARRAY IMPLEMENTATION Amplifiergs & 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 IMPLEMENTATION Amplifier & 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 IMPLEMENTATION Coax Phasing Lines Network or Antenna Analyzer Measure The Resonant Frequency Or Fault Of Open-circuited Line Calculate Phase By Frequency Scaling Dayton 2013 Dayton 2013

FOUR-ELEMENT ARRAY Simulation Results – 160 M Spacing: 100 Ft Amplitudes: 0.42-1-1-0.42 Crossfire Phasing: 0, -190o, -380o, -570o Dayton 2013

FOUR-ELEMENT ARRAY Simulation Results (Cont.) Dayton 2013

FOUR-ELEMENT ARRAY Simulation Results - 80 M Spacing: 100 Feet Between Loops Amplitudes: 0.42-1-1-0.42 Crossfire Phasing: 0, -200o, -400o, -600o Dayton 2013

FOUR-ELEMENT ARRAY Simulation Results - 80 M Dayton 2013

ARRAY IMPLEMENTATION Loop Termination and Switching 560 W Termination DPDT Relay Dayton 2013 Dayton 2013

ARRAY IMPLEMENTATION Loop Design and Array Control 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 Used Loop Support, Direction Control Box, Hi-Z Amplifier Hi-Z Amplifier Direction Control Dayton 2013

4 EL ARRAY IMPLEMENTATION Loop & Controller Individual Loop Controller During Installation Dayton 2013

4 EL ARRAY IMPLEMENTATION Loop Alignment! N/S Array E/W Array Fiberglass Support Poles (Max-Gain Systems) Control Cables and Coax in PVC on Ground Array Looking NE Array Looking SW Dayton 2013 Dayton 2013

ARRAY IMPLEMENTATION System 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 Dayton 2013

ARRAY IMPLEMENTATION System Design Delay 1 Delay 3 Delay 2 Dayton 2013

MULTIELEMENT ARRAY COMPARISONS 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!) Dayton 2013

K9AY LOOPS & SHORT VERTICALS Comparison of Simulation Results Comparison - K9AY Loops (85’) and Verticals (26.5’) # of Elements RDF (dB) Output (dBi) Loops Verticals 1 7.4 4.9 -23.6 5.8 2 10.5 9.8 -25.6 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 VERTICALS Experiment 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

K9AY LOOPS & SHORT VERTICALS Qualitative Results Thus Far 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 Dayton 2013

SUMMARY I Hear Well on the Low Bands The Arrays Act Similar to Yagis 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

REFERENCES Gary Breed, “The K9AY terminated loop – A compact, directional receiving antenna,” QST, vol. 81, no. 9, pp. 43-46, September 1997. Gary Breed, K9AY, "Arrays of K9AY Loops: "Medium-sized" low band RX antenna solutions," Sept. 15, 2007. http://www.aytechnologies.com John Devoldere, ON4UN's Low-Band DXing, Fourth & Fifth Editions, ARRL, Newington, CT: 2005 & 2011. Dallas Lankford, http://groups.yahoo.com/group/thedallasfiles http://www.fcc.gov/mb/audio/m3/index.html Hi-Z Antennas 4-Square, http://www.hizantennas.com DX Engineering 4-Square, http://www.dxengineering.com Max-Gain Systems, http://www.mgs4u.com The Wireman, http://www.thewireman.com 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. Richard C. Jaeger, “Multi-Element End-fire Arrays of K9AY Loops,” QEX, pp. 22-31, Jan./Feb. 2013. Dayton 2013 Dayton 2013

THANK YOU FOR YOUR ATTENTION QUESTIONS? k4iqj@mindspring.com www.k4iqj.com Dayton 2013 Dayton 2013