To: Edgar Castro

From: Jon Hagen

Date: Mar. 2, 2001

Subject: Report for March, 2001

The VLBA/4 terminal arrived from Haystack. It was unpacked, installed in the control room, and connected to the field system pc. Establishing communication over the serial control lines to the MAT bus (Mark IV components) and the MCB bus (VLBA components) was finally accomplished after considerable digging through VLBI memos, calls for help, and experimentation. The system is ready for the upcoming visit of Frank Ghigo from NRAO who will provide on-site training in the operation of this equipment. Signatron, who made the unit for us, passed along the original Haystack documentation, to which they only added one small block diagram and a wiring list for the back plane of the Data Acquisition Rack. We should write our own high-level documentation - a shell to surround around the detailed schematics and detailed low-level VLBI memos.

I spent some time designing a portable reflectometer to be used with full-height and half-height WR2100 waveguide. The heart of this device is a magic T with one waveguide port and three coaxial ports. This component is being designed using the CAD program, HFSS.

A new design was made for a voltage-controlled oscillator to replace old HP synthesizer used with the radar blanker. The new oscillator be mounted inside the blanker and HP synthesizer can be removed from the control room.

I worked with Phil Perillat on Tiedown 4 to reduce noise pickup in the load cell amplifiers. The fixes will be implemented on the other two tie down stations.

A backup was prepared for the OCU computer (Operator Control Unit) in the Vertex pointing system.