Log entry time 16:33:57 on November 30, 2010

Entry number 342087

AM Preliminary investigation found the Unser/Cavity BCM heater ON, and both downconverters (10 kHz) healthy. LO frequencies were measured: US: 1496.991 MHz DS: 1496.985 MHz

DS is 5 kHz too low, and should be re-tuned. I had surmised the IF shift from 10 kHz to 15 kHz might result in amplitude reduction, due to input filter passband of upstairs electronics. After consulting schematic (Figure 1) and subsequent model (Figure 2), this is not the likely cause. However, we do need to know if your readbacks are from: 1 MHz System 10 kHz System (RMS-DC ) 10 kHz System (HP 3458A Multi-meters)

This information will guide us as we continue to discover the root cause of the ~ 10% (1dB) magnitude change from November. For now, nothing was changed.

J. Musson x7441

Figure1: Filter Schematic

Figure 2: Frequency Response (Magnitude)