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Software Defined Radios A Contester’s Perspective

Software Defined Radios A Contester’s Perspective. With thanks to Jeffrey Pawlan, WA6KBL Ilberto di Bene, I2PHD. by Bob Wilson, N6TV n6tv@arrl.net. Visalia DX Convention Contest Forum April 26 th , 2008. This is not a technical talk. I will not try to explain how SDRs work

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Software Defined Radios A Contester’s Perspective

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  1. Software Defined RadiosA Contester’s Perspective With thanks to Jeffrey Pawlan, WA6KBL Ilberto di Bene, I2PHD by Bob Wilson, N6TV n6tv@arrl.net Visalia DX Convention Contest Forum April 26th, 2008

  2. 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

  3. 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

  4. Softrock-40

  5. Softrock 6.1

  6. RFSpace SDR-IQ

  7. Microtelecom Perseus(used to make demo recordings)

  8. FlexRadio Flex-5000A

  9. FlexRadio Flex-5000C

  10. 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 • 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” • Press “RX ANT” button • Rig’s T/R circuit protects SDR front end • QSK works fine

  11. 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 • WinRad Software: 1.4 MB • Recording: 300 MB (zipped!)

  12. 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”

  13. 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

  14. 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)

  15. An SDR on the Web • 40 and 80m remote SDR in the Netherlands • 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”

  16. 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”

  17. 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?

  18. 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?

  19. 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

  20. 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

  21. Discussion

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