Db - Decrease default floor to -150dB.

sdrbase/util/db.h

@@ -26,7 +26,7 @@
 class SDRBASE_API CalcDb
 {
 public:
-	static double dbPower(double magsq, double floor = 1e-12);
+	static double dbPower(double magsq, double floor = 1e-15); // Floor at -150dB
 	static double powerFromdB(double powerdB);
 	static double frexp10(double arg, int *exp);
 };