Receiving Antenna Metrics With Examples

Receiving Antenna MetricsWith ExamplesSteps Beyond Gain and F/BJukka Klemola OH6LIFeb 13th 2018

Practical Presentation is longer than typically seen onWWROFWe will have a short break at about 45 minutesAll antenna model files and the Excel WorkbookRX Ant Metrics will be availale via WWROFAs you have questions, please write themdown. Presentation is longQ&A at the end

Contributors Markku OH2RA Dan AC6LA Frank W3LPL Reino OH3MA Maik DJ2QV Ward N0AX

Contents Traditional Metrics Gmax, F/B Receiving Directivity Factor Directivity Merit Figure Noise Margin Leaking Index Receiving antennas for residential locations Better decent size antennas for rural locations Linear Inline Receiving Array

Antenna Gain Maximum

Antenna Gain Maximum

Antenna Front-to-Back

Antenna Front-to-Back16,1 dB16,1 dB

Antenna Front-to-Back

Cardioid Pattern Antenna0.5wl BOG, Flag, 2xGP

Cardioid Pattern Antenna-3 dB-3 dB-3 dB-3 dB

Cardioid Pattern Antenna-3 dB-3 dB-3 dB-3 dBFor a receiving antennaWhich is considered the 'Better' directionThe receiving sector on right orThe attenuated sector on the left?

Cardioid Pattern Antenna-6 dB or better

Cardioid Pattern Antenna-12 dB or better

Modern Metrics

Receiving Antenna RDFReceiving Directivity FactorRDF isMaximum GainAverage GainCalculated through full hemisphere

Receiving Antenna RDFReceiving Directivity FactorRDF isMaximum Gain [dB]– Average Gain [dB]Calculated through full hemisphere

Receiving Antenna RDFReceiving Directivity FactorRDF isAvailable in EZNEC, AutoEZ, 4nec2

Receiving Antenna RDFReceiving Directivity FactorRDFPrinciple introduced byJohn Devoldere, ON4UN,Low Band DXing, Chapter 7

Receiving Antenna RDFReceiving Directivity FactorRDF is3D numeric calculation

Receiving Antenna DMFDirectivity Merit FigureDMF isMaximum Gain [dB]– Back Half Average Gain [dB]Calculated through back halfhemisphere

Receiving Antenna DMFDirectivity Merit FigureDMF isIntroduced as a 3D itemJohn Devoldere, ON4UNLow Band DXing, Chapter 7

Receiving Antenna DMFDirectivity Merit FigureDMF isNot available

Receiving Antenna DMFDirectivity Merit FigureDMF isNot availableSolution release in this presentation

What are the Metrics Good For? Previously unanswered questions:Does my system hear noise from the band oram I limited by electronics thermal noise?

What are the Metrics Good For? Previously unanswered questions:Does my system hear noise from the band oram I limited by electronics thermal noise?How small my directional antenna can be andstill receive the noise from the band?

What are the Metrics Good For? Previously unanswered questions:Does my system hear noise from the band oram I limited by electronics thermal noise?How small my directional antenna can be andstill receive the noise from the band?Which antenna pattern is better?

RX Antenna Development Small antennas

RX Antenna Development Small antennas Flag, FO0AAA, DoubleKAZ, phased antennas Optimize the antenna size Solution proposal in this presentation Most antennas produce side lobes Pattern may leak despite overall average is goodSolution proposal in this presentation

RX Antenna Development New small antennas use a load to form thepattern Antenna's gain is typically negative in dBi Need to design antenna system level sensitivity Best S/N by cleanest pattern adequate amplificationTransmit antennas integrate all noise Transmit antennas' receiving S/N grows by Gmax

Antenna Metrics Development Computers bring opportunities True 3D pattern data available Idea to Need to Requirement to Specification Calculating is easy

Antenna Pattern DataSample based 3D pattern into ExcelDan, AC6LA, made an automatedinput for MMANA Table Angle / Gainand for EZNEC and 4nec2 .pf3 filesMMANA uses MININECEZNEC and 4nec2 use NEC

Antenna Pattern DataSample based 3D pattern into ExcelDan, AC6LA, made an automatedinput for MMANA Table Angle / Gainand for EZNEC and 4nec2 .pf3 filesMMANA uses MININECEZNEC and 4nec2 use NECZenith, Azimuth, Gain at 1 degreeresolutionFirst calculus to steradiansMath basics:hemisphere surface is 2 Pi

Data to MetricsSample based 3D pattern into ExcelDan, AC6LA, made an automatedinput for MMANA Table Angle / Gainand for EZNEC and 4nec2 .pf3 filesMMANA is MININEC while EZNECand 4nec2 use NEC engineMath basics:hemisphere surface is 2 PiZenith, Azimuth, Gain at 1 degreeresolutionFirst calculus to steradiansThen average gain to get RDFand back half average to get DMF

RX Ant Metrics WorkbookRead MMANA .csv File

RX Ant Metrics WorkbookRead MMANA .csv File

RX Ant Metrics WorkbookRead EZNEC or 4nec2 pf3 File

RX Ant Metrics OutputsFront sheet - Avg Gain RDF DMFRDF algorithm same as EZNECDMF available as a new item

RX Ant Metrics OutputsNoise Margin estimates if the receiving system is limited byelectronics thermal noiseThat is, if antenna's Average Gain is big enough to hear theband noise over the receiver's thermal electronics noise

RX Ant Metrics OutputsLeaking Index tells if the antenna pattern leaks outside the Main Lobe

RX Ant Metrics OutputsSummary of Metrics gives an easy to copypaste data set to acollection workbook

New Antenna Metrics Explained

Noise Margin The Sky provides noise to antenna Noise is mostly man-made or atmospheric Directional antenna receives noise bycalculated average gain in relation to fullhemisphere noiseSmaller antenna with smaller amplificationreceives less noise

Noise Margin The Sky provides noise to antenna Noise is mostly man-made or atmospheric Directional antenna receives noise bycalculated average gain in relation to fullhemisphere noiseSmaller antenna with smaller amplificationreceives less noiseTo hear the weak signals, the noise levelreceived from the Sky must exceed the noise ofelectronics, the thermal noise, by a margin

Noise Margin We can calculate the noise power we receive Thermal electronics noise equals Noise Figure We want to have a small, yet highly directiveantenna and receive the smallest possiblesignalsThat is, we want to hear the band noise at mainlobe -3dB points and have the smallest feasibleantennaWe need to understand and evaluate theantenna system Noise Margin

Noise LevelITU-R P.372-13

Noise LevelITU-R P.372-13Shows 46 dBnoise on 160 at 1Hzbandwidth for a quietrural receiving site64dB for a residentialarea receiving site

Noise LevelITU-R P.372-13Shows 46 dBnoise on 160 at 1Hzbandwidth for a quietrural receiving site64dB for a residentialarea receiving siteValidation for NoiseLevel comes from ITU

Noise LevelITU-R P.372-13Shows 46 dBnoise on 160 at 1Hzbandwidth for a quietrural receiving site64dB for a residentialarea receiving siteA B C Noise Levels arestatistical medianD is minimum noiselevel expected

Noise Distribution Noise distribution is even for dA(sr) steradiansurface elements through the hemisphereNoise Mask can be used but Excel file size growsfrom 5MB level to 8M Low angle man-made noise likely dominates0 to 2 degrees elevation gain is small, attenuatesthe low angle noise, lowers importanceLow angle emphasizing noise mask algorithmprototyping showed less than 1 dB differenceNoise Margin algorithm can be improved

Noise LevelCalculate in dB:Noise Level Antenna Gaverage

Noise Level at ConnectorCalculate in dB:Noise Level Antenna Gaverage- Feed System Losses Noise Level atantenna system outputconnector at MainLobe Gmax

Noise Level at -3dB pointsCalculate in dB:Noise Level Antenna Gaverage- Feed System Losses- 3 dB Noise Level atantenna system outputconnector atMain Lobe – 3 dBpoints

Receiver Noise FigureRX Noise FigureReceiver Noise Figurestands on the bottom,limiting the receivingsystem sensitivity

Noise MarginCalculate in dB:Noise Level Antenna Gaverage- Feed System Losses- 3 dB- RX Noise Figure Noise Margin

Noise MarginCalculate in dB:Noise Level Antenna Gaverage- Feed System Losses- 3 dB- RX Noise Figure Noise MarginNoise Margin givesroom for Noise Levelchanges

Noise Margin in RX Ant Metrics

Noise Margin in RX Ant Metrics

Leaking Index

Leaking Index Leaking Index tells how much the antennapattern leaks to unwanted directions

Leaking Index Leaking Index tells how much the antennapattern leaks to unwanted directions Default 80 to 280 degrees AzimuthThe antenna is better when Smaller proportion of pattern leaks Any leaking is attenuated moreThe percentage of leaking is calculated at threelevels; Gmax -12 dB, -18 dB and -24 dB.Leaking Index is the average percentage ofleaking at these three levels

Leaking Index

Leaking Index8028090

Leaking Index8028090

Leaking Index8028090

Leaking Index80280Three levels-12 dB-18 dB-24 dB90

Leaking Index in RX Ant Metrics

Leaking Index in RX Ant Metrics

Leaking Index Bottom Line RDF and DMF are general averagingcalculationsLeaking Index brings up only the amount ofleakingLeaking index calculates more than back halfand is configurable for narrower Main LobesLeaking Index can be the final decision makingcriteria where RDF and DMF provide uncleardifferentiation between antennas

Leaking Index Limitations Leaking index is currently limited to 0-90elevationForward looking high elevation angles are notcounted inLeaking Index drives to improve the pattern to-24 dB level, not furtherLeaking Index algorithm can be improved

Examples

Examples Various antenna examples Also a new antenna concept

Examples FO0AAA triangle / delta Beverage Twin Triangle Linear Inline targetX Antenna - LIXA Staggered beverage Linear Inline Receiving Array - LIRA

Triangle AntennaLoadIdea from Earl K6SEFeedpoint

Triangle AntennaTriangle HeightBottom Wire HeightBottom Wire LengthConstruction WidthWireLoadFeed5.5m (18'4“)3m (10')8m (26'6“)3m (10') struts/guys4mm Cu820-850 ohm800 ohmLoadFor all antennasFeedpoint

Triangle AntennaTriangle HeightBottom Wire HeightBottom Wire LengthConstruction WidthWireLoadFeed5.5m (18'4“)3m (10')8m (26'6“)3m (10') struts/guys4mm Cu820-850 ohm800 ohmEasy to install feed pointLoad placement optimized for patternLoadAlmost like FO0AAA triangle/deltaby Earl K6SEFeedpoint

Triangle Metrics

Triangle RDF, DMF

Triangle Noise Margin

Triangle Noise MarginQuiet Rural QTH

Triangle Noise MarginResidential QTH

Triangle Noise MarginResidential QTH-5.4 dB to 12.6 dB difference comes from changeto Residential from Quiet Rural

Triangle Noise MarginResidential QTH-5,4 dB to 12,6 dB difference comes from changeto Residential from Quiet RuralThat equals receiving site Noise Level change from 46 dB to 64 dB

Triangle Leaking Index

Comparison

Bigger TriangleTriangle HeightBottom Wire HeightBottom Wire LengthConstruction WidthWireLoadFeed7.5m (25')3m (10')15m (50')3m (10') struts/guys4mm Al830-850 ohm800 ohm

Bigger Triangle

ComparisonNoise Margin increased to 2.1 dB from -5,4 dB2,1 dB is not a good enough Noise Margin for theabsolute most quiet QTH

Smaller TriangleRESIDENTIALConstruction HeightBottom Wire HeightBottom Wire LengthConstruction WidthWireLoadFeed6m (20')3m (10')5m (13'4“)2m (8') struts/guys4mm Al740-760 ohm800 ohm

Smaller TriangleRESIDENTIAL

ComparisonNoise Margin shows 3,4 dB at a Residential QTHFor a 5 meters long antenna, the result is surprising

Smaller Triangle 80mRESIDENTIAL

Smaller Triangle 80mRESIDENTIAL

Comparison5 m long, 6m high Triangle antenna justabout functions in a residential area QTH

Beverage 170mTotal construction length 170m (558')Wire height 3m (10')Construction width 2m (6'7“) with strutsLoads 820-850 ohmFeed 800 ohm (0 and 180 deg)Feed 600 ohmLoad 450 ohm

Beverage 170m

Beverage 170m

Beverage 170m Leaking Index

Comparison

Beverage 250m

Beverage 250m Leaking Index

Beverage 250m

ComparisonBeverages show their power compared to the smallest antennas

Twin TriangleTotal construction length 58m (190')Bottom wires at 3m (10')Bottom wire lengths 24m (78'9“)Triangle height 9,5m (31'2“)Construction Width 3m (10')Wire 4mm AlLoads 840-860 ohmFeed 800 ohm (0 and 180 deg)

Twin Triangle

Twin Triangle RDF DMF

Twin Triangle Noise Margin

Twin Triangle Leaking Index-12 dB or better attenuation level area widerthan Leaking Indexdefault 80-280 degrees

Twin Triangle Leaking Index-12 dB or better attenuation level area widerthan Leaking Indexdefault 80-280 degrees