To: Edgar Castro

From: Jon Hagen

Date: April 12, 2000

Subject: Monthly report for February and March, 2000

New axles were made in Ithaca to refurbish the old 430 collector (high-power traveling waveguide probe). This collector which will be kept as a spare when the two new collector have been installed. All the pieces for the first new collector have been made in Ithaca and welding will begin in April.

HFSS was used to design a short tuning post to bring the center frequency of the new half-height turnstile down to 430 MHz from 435 MHz. The post was built in Ithaca and shipped to Arecibo. The waveguide transition for the turnstile's receiver port was changed to use a larger 1 5/8"

diameter coax. A calibration kit - three shorts - was built to calibrate the network analyzer for this size line.

Parts have been received for the new PIN diode receiver protectors used in the 430 MHz radar system. Construction of these units should begin in April.

The first rebuilt klystron from California Tube Labs will be shipped soon to Millstone. Arecibo continues to operate with a single klystron and hopes to receive one of the first rebuilt tubes.

Improvements in the lightning protection system, control system, and documentation continue to be made to the active tie-down stations.