To: Edgar Castro

From: Jon Hagen

Date: July 14, 2000

Subject: Report for July, 2000

Mechanical adjustments were made to the side rollers of the new collector, and it has been taken to the platform to be installed on the carriage house for high power tests. The new turnstile is also being installed in order to determine the exact dimensions of the removable waveguide section needed to make the change-over from radio astronomy operation to radar operation.

A second klystron was shipped to California Tube Labs for rebuilding. The first rebuilt tube continues to operate with a higher than normal vacuum - but, it continues to operate. "Flashing" the filament did not speed up what seems to be a long outgassing process.

Some preliminary development work is being done to investigate possible designs for dual- polariztion waveguide cold loads that would allow us to calibrate receivers in situ. A summer student, Miguel Irizarry, has been using the HFSS finite element modeling program to model circular waveguides containing various absorber shapes.

Signatron is correcting a problem with the write circuitry in the VLBI terminal they are building for Arecibo. We are arranging to send the unit to Haystack (where it was designed) for final testing before it is shipped to Arecibo. We have the parts to build phase calibration units for several of our receivers and will soon assemble these units.

One 430 MHz flexible waveguide section was sent to a local company to be shortened. On a second attempt, the work appears satisfactory. Meanwhile, the company that originally built the flex guide sections, Airtron, has been slow to respond to our requests for quotations to do this work.