Presentation on theme: "Software Defined Radios A Contester’s Perspective by Bob Wilson, N6TV Visalia DX Convention Contest Forum April 26 th, 2008 With thanks to."— Presentation transcript:
Software Defined Radios A Contester’s Perspective by Bob Wilson, N6TV firstname.lastname@example.org Visalia DX Convention Contest Forum April 26 th, 2008 With thanks to Jeffrey Pawlan, WA6KBL Ilberto di Bene, I2PHD
This is not a technical talk I will not try to explain how SDRs work I will try to show how they could be used by contesters
What you will see Brief overview of some available SDR hardware Demo of WinRad software, by I2PHD The “Waterfall display” Demo of CW Skimmer by VE3NEA An SDR on the Web Implications and Discussion
How to add an SDR “Band Scope” to your current transceiver Feed IF out to an SDR tuned to IF freq. - or - Share your transmit antenna with an SDR receiver 1.Connect “Rx Ant Out” to input of a 2-way Power Splitter Output 1 SDR’s “Antenna” connector Output 2 Rig’s “Rx Ant In” 2.Press “RX ANT” button Rig’s T/R circuit protects SDR front end QSK works fine
WinRad demo Playback of a 10 min. recording made with a Perseus SDR Captured low end of 20m (~ 122 kHz wide) Antenna: 5 ele 20m yagi, 42’ boom Instructions at http://www.kkn.net/~n6tv http://www.kkn.net/~n6tv – WinRad Software: 1.4 MB –Recording: 300 MB (zipped!)
Advantages of the “Waterfall” Display Scan a band with your eyes instead of your ears You can see faint signals and “new” signals You can find “holes” where you can call CQ –Or call in a pileup Clicking is faster than turning a knob Significant improvement over legacy “band scopes”
CW Skimmer Demo CW Skimmer running in “3 kHz mode” With a compatible SDR, you could watch up to 96 kHz of a band with CW Skimmer
CW Skimmer CW Skimmer = Code reader + bandscope Simultaneous decoding of multiple channels Another program can take CW Skimmer output and feed it into your contest software “bandmap” window –Or automatically post packet spots to a remote cluster (e.g. N4ZR)
An SDR on the Web 40 and 80m remote SDR in the Netherlands http://websdr.ewi.utwente.nl:8901/ http://websdr.ewi.utwente.nl:8901/ Note: contest rules generally prohibit the use of remote receiving sites, even for M/M –They are not within the property limits / 500m circle –They are not spotting nets –They are not a “remote base” But great for “testing propagation”
The CW Skimmer Controversy Can single-ops legally use a local CW Skimmer in a contest? –Code readers are not prohibited –Band scopes are not prohibited –A local CW Skimmer is not a spotting net –Nothing in ARRL rules seems to prohibit it –CQ WW rules may prohibit it if K3EST says CW Skimmer counts as “other DX Alerting Assistance”
Editorial Opinion CW Skimmer represents a major advance in the radio arts It is far from perfect – banning them now seems premature Let the radio arts advance We never banned tape recorders, memory keyers, computer sent CW, computer logging, super check partial windows, pre-fill databases, code readers, band scopes, etc., so what’s the big deal?
Remember the Turbine-powered car? Built by Andy Granatelli of STP Entered in 1967 and 1968 Indy 500 –Driven by Parnelli Jones, Joe Leonard Almost won both races Never “banned” outright but … –So outclassed everything else that USAC reduced the allowable intake area sufficiently to strangle the engines and render them non-competitive. Should we write rules that stifle innovation?
What you just saw SDR hardware Demo of WinRad and the “Waterfall display” Demo of CW Skimmer by VE3NEA An SDR on the Web Still missing: integration of SDRs with contest software
What’s Next? RTTY Skimmer? SSB Skimmer? A “robot” – a totally automated op? –“Z80 OP” – developed by N6TR, in 1986! Let’s sponsor an “X-Prize” –First totally automated op. to make Top Ten box in the CW NA Sprint Competition encourage advancements in the radio arts –Don’t write rules that stifle innovation