Beam Steering on 160 MetersHamSDRAmateur Radio 光束转向160米hamsdr业余无线电.ppt
Beam Steering on 160 Meters,Victor Kean,K1LTContest ForumDayton HamventionMay 17,2008,2 Element End-Fire Array,Classic cardioid patternNull aimed up about 20 degrees,4 Element Broadside Array,Bidirectional pattern1:1:1:1 amplitude assignment for max directivity,4 Element Broadside Array,Bidirectional pattern1:3:3:1 amplitude assignment for no sidelobes,8 Element Broadside/End-Fire Array,Product of end-fire and 1-1-1-1 broadside patternsEnd-Fire null not as wide as broadside main lobeMany back and side lobes yet max directivity,8 Element Broadside/End-Fire Array,Product of end-fire and 1-3-3-1 broadside patternsEnd-Fire null not as wide as broadside main lobeLeaves two little back lobes,8 Element BS/EF Array Steered,Pattern broadens as steered away from normalUsing no-sidelobe 1-3-3-1 feed patternSteered 10 degrees,20 degrees,8 Element BS/EF Array Steered II,Pattern broadens as steered away from normalPattern degenerates to bidirectionalSteered 30 degrees,40 degrees,8 Element BS/EF Array Steered III,Pattern broadens as steered away from normalAfter 60 degrees,secondary lobe becomes biggestSteered 50 degrees,60 degrees,8 Element BS/EF Array Numbers,8 Element BS/EF Array Numbers,RDF Compared to Other Antennas,Short Vertical Design,Slightly scaled W8JI short vertical designMore numerous but shorter radials,Array Layout,North to the left,Africa is upNeeds more real estate than a Beverage,Array of Arrays,Each pair(1&5,2&6,etc.)is an end-fire arrayThere are 4 end-fire arrays in phase,End-Fire Reversing Switch,Decouples relay power from feedlineFirst transformer inverts signal from east verticalSecond transformer converts 37 to 75Phasing specs from ON4UNs book,Block Diagram,M-Audio Delta 1010LT,Softrock v6 Receivers&DDS 6.0 VFO,Calibration is Annoying,Softrock input filter very inconsistentAntennas vary despite careful tuningCalibration accommodates inconsistencyUse of off-site signal best calibration strategyIn-shack calibration source seems almost good enough,Typical Screen Content,Computer Requirements,Just a guess based on my computerFaster than 1.5 GHzProbably 512 megabytes RAMPCI slot for the Delta 1010LTSerial or USB to control frequencyHuge hard drive if you want to make recordings,Software Requirements,Linux 2.6.18 or laterReal Time patchesJack Audio Connection Kit(JACK)DttSP(see dttsp.org for other requirements)SDR_Shell(ewpereira.org/sdr-shell)My phasing softwareNumerous other packagesEventually I will document installation,Advantages,Continuously steerableOptimal best RDF for the real estateFlexible broadside,end-fire,circle,etc.Panoramic display is built-inMultiple outputs simultaneously,Disadvantages,SDR versus traditional radio tradeoffs:Latency versus selectivityWide front end versus narrow front endIntegration:not just an antenna,its a radioLack of knobs,Future Work,Active elements facilitates experimentation9 Element circle array5 Element end-fire arrayIntegrate receiving system with transmitterTransmit beam steering,
