Trans-Ionospheric Pulse Pairs (TIPPs) have been detected by the Blackbeard instrument aboard the ALEXIS spacecraft in the VHF band between 28 and 166 MHz with dispersion indicating a subionospheric source. Using a database that runs from 2 November 1993 to 19 November 1996, the rate and diurnal variation of TIPP detection are calculated for central Africa, Indonesia, and North America. The rate of TIPP detection by Blackbeard in the frequency band from 28--95 MHz is 0.02 and 0.04 TIPPs per second for central Africa and Indonesia respectively. For North America the data were acquired in a narrow band from 28--37.9 MHz and the TIPP detection rate is 0.007 events per second. The diurnal variation of TIPPs resembles the diurnal variation of CG lightning during daylight hours. However the TIPP production remains strong through midnight and into the morning hours, whereas CG flash production tends to decrease more sharply after peaking around 4 PM local time. Thus the diurnal variation suggests that TIPPs are not produced in CG flashes, a conclusion consistent with their correlation with intracloud pulses. ¿ 1998 American Geophysical Union