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Selected Topics In Propagation 15m/12m/10m Long Path

Selected Topics In Propagation 15m/12m/10m Long Path. Carl Luetzelschwab K9LA k9la@arrl.net. What We’ll Cover. 10m long path My first experience K2ARO 10m long path data Skeds with JH3DPB Recent openings Apply East Coast knowledge to other parts of the US

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Selected Topics In Propagation 15m/12m/10m Long Path

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  1. Selected Topics In Propagation15m/12m/10m Long Path Carl Luetzelschwab K9LA k9la@arrl.net PVRC Webinar May 2011 K9LA

  2. What We’ll Cover • 10m long path • My first experience • K2ARO 10m long path data • Skeds with JH3DPB • Recent openings • Apply East Coast knowledge to other parts of the US • Apply 10m knowledge to 15m and 12m • Summary PVRC Webinar May 2011 K9LA

  3. Quick Cycle 24 Update Latest smoothed sunspot number is 23.2 for October 2010 Extrapolate to April 2011 – about 40 Latest smoothed 10.7 cm solar flux is 85.3 for October 2010 Extrapolate to April 2011 – about 95 PVRC Webinar May 2011 K9LA

  4. 10m Long Path PVRC Webinar May 2011 K9LA

  5. An Interesting Night . . . . • Spring of 1980 when I lived in the Dallas/Ft Worth area • Heard a DL on 10m CW around 11:00 PM • His signal peaked towards the southwest • Kind of weak • My first introduction to 10m long path PVRC Webinar May 2011 K9LA

  6. An Interesting Day . . . . • CQ WW SSB 1986 • Early morning • One of the D/FW locals called in on the 2m net • VS6DO was on 10m via long path • Great signal, easy to work PVRC Webinar May 2011 K9LA

  7. I Was All Fired Up • But then we moved back north • I wasn’t back on the air until late 1988 • Read Jerry N6AV’s (SK) article “10 Meter Long Path” in the January 1989 issue of the DX Magazine • It was slanted towards the West Coast, of course, but that got me going again PVRC Webinar May 2011 K9LA

  8. Lots of Good Data • Ran into Gus K2ARO on 10m in late 1991 • He had lots of log data on 10m long path to JA and VK6 • I used his log data to create plots • Openings vs SSN • Seasonal variation • Duration of Openings • Let’s look at this data PVRC Webinar May 2011 K9LA

  9. K2ARO: Long Path to JA short • Short path is 11,000 km • High northern latitudes in darkness a long time • Long path is 29,000 km • Two transits across the robust equatorial ionosphere • High southern latitudes in daylight • Need sunrise at K2ARO • JA can be past sunset, but not too long past sunset • F2 recombination after sunset is much slower than ionization at sunrise • Long path goes over VK6 K2ARO JA April 15 long sunrise on one end, not too far past sunset on the other end PVRC Webinar May 2011 K9LA

  10. K2ARO: Openings vs SSN Looks like a smoothed sunspot number greater than about 60 gives 10m long path PVRC Webinar May 2011 K9LA

  11. K2ARO: Seasonal Variation • Both paths are available from March through October • VK6 appears to have a drop-out in summer to JA to VK6 PVRC Webinar May 2011 K9LA

  12. K2ARO: Duration of Openings • 1979 – average 14 minutes • 1980 – average 16.3 minutes (longest 2 hours 7 minutes) • 1981 – average 28.5 minutes • 1982 – average 26 minutes • 1988 – average 24.7 minutes • 1989 – average 30.9 minutes (longest 2 hours 42 minutes) • 1990 – average 20.4 minutes • 1991 – average 23.5 minutes • 1992 – average 42.6 minutes (longest 1 hour 40 minutes) Overall average = 23 minutes PVRC Webinar May 2011 K9LA

  13. What About the Terminator? • 10% of K2ARO’s JA QSOs were before the spring equinox and after the fall equinox • 23% of K2ARO’s VK6 QSOs were before the spring equinox and after the fall equinox • Prior to the spring equinox and after the fall equinox the overhead Sun is in the southern hemisphere • More absorption along long path K2ARO JA March 8 terminator important for sunrise on one end PVRC Webinar May 2011 K9LA

  14. What About East Coast Sunset? Let’s reverse the path Look for path with one end just after sunrise and not too far past sunset on W2 end VU area fits the bill April 15 path should be there – but not a high ham population PVRC Webinar May 2011 K9LA

  15. Met JH3DPB on 10m LP • We set up daily skeds in April 1992 • Yuu ran a TS-930 barefoot to a 6-element monobander at 110 feet • I ran a TS-180 barefoot to a 4-element monobander at 72 feet • QSOs possible on many days • Two days were noteworthy PVRC Webinar May 2011 K9LA

  16. Noteworthy Days • Contact established at 1100 UTC • 6:00 AM local for me, 8:00 PM local for Yuu • Contact maintained until 1315 UTC • 8:15 AM for me, 10:15 PM for Yuu • Opening sudden in nature • Had to wait for MUF to rise on my end • Closing was a gradual decrease in signal strength • Absorption increased as the sub-solar point moved closer to the path • 2 hours 15 minutes • Could have lasted even longer with amplifiers on both ends • Falls in line with K2ARO’s longest opening PVRC Webinar May 2011 K9LA

  17. Recent Openings PVRC Webinar May 2011 K9LA

  18. W3LPL & K3LR in 2011 ARRL DX • K3LR on 10m in 2011 ARRL DX • CW (19, 20 Feb) • No JAs (or any SE Asia) via long path • Nothing on short path, either • PH (5, 6 Mar) • 4 long path QSOs • 3 JAs and 1 BV • 1236 – 1310 UTC on Sunday morning • 4 short path QSOs with JA • 3 on Saturday evening between 2149 - 2154 UTC • 1 on Sunday evening at 2133 UTC • N4QQ at W3LPL reported similar openings • W3LPL & K3LR on 15m in 2011 ARRL DX • Nothing obvious, but this is not surprising as long path would be at the same time as the morning EU opening • Other recent reports • I’ve seen reports of 15m, 12m, and 10m long path PVRC Webinar May 2011 K9LA

  19. Apply East Coast Knowledge to Other Parts of the US PVRC Webinar May 2011 K9LA

  20. East Coast vs West Coast • W6 to JA long path is 2000 km longer than W2 to JA long path • JA is farther into the dark ionosphere W2 W6 JA JA April 15 April 15 W6 should have an opening to a QTH west of JA (closer to sunset) PVRC Webinar May 2011 K9LA

  21. West Coast Openings EU W6 W6 VU Mideast April 15 W6 to VU area at W6 sunrise (but not a high ham population) W6 to Mideast & EU after W6 sunset (good opening - N6AV wrote about it) PVRC Webinar May 2011 K9LA

  22. Interesting Pattern East Coast has good long path opening after sunrise East Coast should have long path opening after sunset, but population not there on other end West Coast has good long path opening after sunset West Coast should have long path opening after sunrise, but population not there on other end How about QTHs in between the East Coast and West Coast? Could they have two opportunities – one at sunrise and one at sunset? PVRC Webinar May 2011 K9LA

  23. Texas – Sunrise and Sunset EU Texas Mideast Texas SE Asia There should be two opportunities for long path PVRC Webinar May 2011 K9LA

  24. NT5C Log • John NT5C provided his log • March 1989 through April 1992 • 10m long path after sunrise • BY, JA, KH6, P2, S2 VK, VR2, YB • 10m long path after sunset • A9, DL, EA, F, FR, HA, HB, HZ, I, LY, OK, ST0, UA, UA9, UB, UH, UI, UL, VQ9, VU, YU, Z2, ZS, 3B8, 5H, 5Z, 9K PVRC Webinar May 2011 K9LA

  25. Apply 10m Knowledge to 15m and 12m PVRC Webinar May 2011 K9LA

  26. 15m and 12m • K2ARO’s data says a smoothed sunspot number of 60 is needed for consistent 10m long path openings • That agrees with VOACAP predictions • Similar work with VOACAP says 15m long path should be possible when the smoothed sunspot number is greater than 25 • We’re past that, so look for 15m long path now • And 12m long path should be possible when the smoothed sunspot number is greater than 40 • We’re right around that now • Remember that the F2 region is very dynamic on a day-to-day basis, so we’ll see intermittent cases of 12m and 10m long path before the smoothed sunspot number reaches 40 and 60, respectively (example: K3LR and W3LPL QSOs on 10m in 2011 ARRL DX PH) PVRC Webinar May 2011 K9LA

  27. Summary of 15m/12m/10m LP • Best months are March through October • East Coast • After sunrise to JA and SE Asia • After sunset to VU area – but lack of ops on this end • West Coast • After sunset to Mideast and EU • After sunrise to VU area – but lack of ops on this end • Texas • After sunrise to JA and SE Asia • After sunset to Mideast and EU • Bands • 15m should be happening now • 12m should get better this summer (per Cycle 24’s ascent so far) • 10m should get better this fall (per Cycle’s 24 ascent so far) PVRC Webinar May 2011 K9LA

  28. Q & A PVRC Webinar May 2011 K9LA

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