Selected Topics In Propagation 15m/12m/10m Long Path Carl Luetzelschwab K9LA k9la@arrl.net PVRC Webinar May 2011 K9LA

What We’ll Cover 10m long path Recent openings 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

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

10m Long Path PVRC Webinar May 2011 K9LA

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

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

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

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

K2ARO: Long Path to JA Short path is 11,000 km Long path is 29,000 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 short K2ARO JA April 15 long sunrise on one end, not too far past sunset on the other end PVRC Webinar May 2011 K9LA

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

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

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

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

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 14

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

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

Recent Openings PVRC Webinar May 2011 K9LA

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

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

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

West Coast Openings W6 to VU area at W6 sunrise 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

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 22

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

NT5C Log John NT5C provided his log 10m long path after sunrise 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

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

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

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 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

Q & A PVRC Webinar May 2011 K9LA