HANG GLIDER PLT WAS INVOLVED IN NMAC WITH A CORPORATE JET WHILE GLIDING ABOVE 10000 FT IN THE LOS ANGELES BASIN.

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AT THE TIME OF THE INCIDENT; I HAD JUST COMPLETED A CLB TO APPROX 10500 FT MSL AND WAS EXITING THE THERMAL. I OBSERVED THE APCHING JET ALREADY CLOSE TO ME AND NEAR/AT MY ALT. WINGS LEVEL; IT WAS ON COURSE TO PASS JUST E OF MY POS. MY HDG WAS ALREADY WBOUND EXITING THE THERMAL. I ACCELERATED (DOVE) TO MAXIMIZE SEPARATION AND MINIMIZE THE RISK OF WAKE TURB. TFC IS A REGULAR CHARACTERISTIC OF THIS AREA AND SURVEILLANCE/AVOIDANCE IS THUS A PRIORITY. NORMALLY; A THERMAL INVERSION CAPS HANG GLIDER OPS AT APPROX 5000 FT MSL. UNDER THESE CONDITIONS; CHIEF CONCERNS ARE FROM DSNDING; SBOUND TFC: COMMERCIAL ACFT; INBOUND TO BUR ARPT; DSNDING ACROSS THE RIDGELINE AT 4000-5000 FT APPROX 2 NM E OF THE INCIDENT LOCATION; AND GA ACFT; INBOUND TO WHITEMAN; BUR AND VNY ARPTS; DSNDING THROUGH THE PACOIMA DAM PASS AT 2500-4500 FT APPROX 4 NM ESE OF THE INCIDENT LOCATION. SCAN ATTN; ALTHOUGH SPREAD UP/DOWN AND IN ALL DIRECTIONS; CAN BE PRIORITIZED UPON THESE FAMILIAR TFC PATTERNS. DSNDING TFC IS COMPARATIVELY EASY TO SPOT AGAINST A BACKGND OF SKY; RATHER THAN GND. AND; BOTH COMMERCIAL AND GA PLTS ARE AWARE OF HANG GLIDER OPS IN THE AREA AND HEIGHTEN THEIR OWN SCANS; AS WELL. HOWEVER; THE DAY'S UNUSUAL WX CONDITIONS CHANGED THIS TYPICAL BAL OF TFC CONCERNS. ABSENT AN INVERSION; THERMAL CLBS TO MORE THAN 10000 FT MSL WERE POSSIBLE. THESE CLBS ADDED A DIFFERENT TFC MIX; INCLUDING GA OPS THROUGH/ABOVE THE NEWHALL PASS; JET TFC CLBING OUT OF VAN NUYS; AND CRUISE TFC ALONG V165. ATTN HAD TO BE SPREAD AMONG CLBING; DSNDING; AND CRUISE TFC ON ALL HDGS. HAVING LEFT LIFT; I WAS DSNDING. THE JET WAS THUS INITIALLY BELOW ME AND DIFFICULT TO DETECT AGAINST THE URBAN BACKGND TO THE S OF MY POS. DESPITE HEIGHTENED AWARENESS; I DID NOT SPOT IT UNTIL IT WAS ALREADY CLOSE TO MY POS. AND I WOULD SUSPECT THAT THE JET'S PLT MAY NOT HAVE BEEN EXPECTING HANG GLIDER TFC AT +10000 FT. EVASIVE ACTION WAS POSSIBLE AND WAS TAKEN. HOWEVER; THE GOAL MUST BE TO REDUCE THE RISK OF A SIMILAR CLOSE ENCOUNTER IN THE FUTURE. THE SIMPLE AND OBVIOUS ANSWER IS THAT I MUST AND SHALL CONTINUE TO IMPROVE MY TFC SCAN SKILLS; ESPECIALLY IN TERMS OF DETECTING CLBING (OR SLIGHTLY-LOWER-ALT) TFC AGAINST AN URBAN/TERRAIN BACKGND. HOWEVER; I ALSO PLAN TO INVESTIGATE THE FEASIBILITY OF MOUNTING A PORTABLE COLLISION ALERT DEVICE AND/OR A XPONDER ON MY HANG GLIDER. SUCH A DEVICE WOULD BE ESPECIALLY USEFUL ON DAYS WHEN WX CONDITIONS PERMIT OPS TO HIGHER-THAN-NORMAL ALTS AND FURTHER AWAY FROM OUR NORMAL PRACTICE AREA. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THIS LOCATION IS POPULAR FOR HANG GLIDING ACTIVITY. A LAUNCH SIGHT IS NEARBY; AND A SUITABLE LANDING AREA IS AVAILABLE. THE ALT ATTAINED IN THIS REPORT WAS UNUSUAL. WHEN CONDITIONS PREVAIL TO ALLOW HIGHER ALTS TO BE ACHIEVED; AN ATTEMPT IS NORMALLY MADE WITH THE LOCAL FSS TO ISSUE A NOTAM. SUCH WAS NOT THE CASE IN THIS INSTANCE.