Originally Posted by
james michael
Tren
Question at your leisure - the radar surveillance data between the two recorded flights of TNP seemed to work lower on the earlier event when the wx was better.
Do you get much variation in the capability (due refraction, scatter, etc?) between a bright sunny day and a day of heavy cloud/rain?
Can't honestly say I've ever paid enough attention to correlating wx conditions to radar coverage to say...
Certainly radar coverage around the BLA/AY/CRG area does vary greatly from day to day, and even intraday. Night time seems to have particularly poor coverage around CRG - we regularly lose SW4 off radar for 50-80 miles at FL150 down the CB-CRG-ELW track. Atmospherics perhaps similar to HF (and to a lesser extent VHF) signals?
Today I had an SR22 overhead AY at A090 who mostly stayed on radar, but ended up dropping off for a few minutes. The SF34 inbound from ML behind him dropped off at A067 while the inbound DH8C from SY dropped off around A059. That's fairly typical of most days - lighties over the top will disappear for between 1 and 10 minutes depending on the strength of their transponder; turboprops and the virgin jungle jet around A060 to the north and A070-A090 to the south.
I've had bad days where I lose lighties for the best part of 1/2 an hour, and don't see the RPTs below F120. I've had good days where I've watched a PA28 from the north track almost all the way into the cct at A030.