To: Edgar Castro

From: Jon Hagen

Date: 2-5-99

Subject: Monthly report for Jan. '99

The overspeed limiter was connected into the emergency stop loop and tested.

The second unit (for the carriage house) was received from Ithaca. Its control box is being assembled at Arecibo and installation should take place in February.

The effort to update the instruction manual and schematics for the 430 MHz transmitter is about 70% complete. Using a generator and a carefully calibrated power meter, the waveguide loss was found to be 1.2 dB +/- 0.1 dB. This value is probably normal. The expected loss of the 1400 run of WR2100 is 0.48 dB. The remaining 0.7 dB loss is distributed among the other components: the coax-to-waveguide transitions used in the measurement, the rotary joint, the 5- probe tuner, the slotted line, and the travelling collector. As time permits, we will measure these individual losses to better understand the overall loss budget.

Work is underway to diagnose the troublesome and unexpected stopping of the tiedown drive systems. The motor power supplies go into foldback after two seconds of overload. But even after foldback, the current should still be sufficient to drive the motors. We will check the jacks for mechanical binding.

Bill Sisk and I have blocked out a new design for the tertiary drive systems. In this design, local control will not require the local computer. We think that we could have this part of the system working within two or three months.

Paul Goldsmith has suggested that the Gregorian 430 radar project be simplified to use a bolt-in rather than a motorized waveguide connection. This would perhaps leave enough space for a turnstile and eliminate the need to build a quarter-wave plate and the need to rebuild the dual- linear OMT. Meanwhile, we will check the fit of the spare collector in the new slotted waveguide.