VLBA RFI Bulletin 26: GPS Jamming Continues at WSMR in April: Scheduled testing of GPS jamming equipment will continue at the White Sands Missile Range during April, 1999. The GPS jamming tests are scheduled for Tuesdays, Thursdays, and Saturdays. Observers using the VLBA-PT and VLBA-LA receivers should expect an increased chance of RFI at the 2 GPS frequencies of 1575 MHz (L1) and 1228 MHz (L2) during the scheduled jamming times. The detailed schedule for April, 1999 follows: Tuesdays: 0601 UTC to 1000 UTC Thursdays: 0601 UTC to 1000 UTC