Tait TB8100 User Manual

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TB8100 Calibration Kit User’s Manual Calibrating the TCXO 23Setup forUnbalanced LineInTo calibrate the unbalanced input and output lines1. Ensure you are already connected to the reciter.2. Select the Reciter Calibration tab, and double-click Unbalanced LineCalibration. The Unbalanced Line Calibration Wizard appears.3. Attach an AC millivoltmeter to the unbalanced line output, and then clickNext.4. Adjust the slider in the dialog box until the audio level on the millivoltmeterreads 1 V PP (0.354 V RMS) to calibrate the unbalanced line output, and thenclick Next.Note: Click Coarse to roughly adjust the audio level, and once youget within range, click Fine for more precise control over thesettings. To move up or down 10 mV PP, click either side of theslider bar.The unbalanced output is now calibrated.5. Connect the unbalanced output to the unbalanced input, and then clickFinish.The unbalanced input is now calibrated.When you have finished calibrating the unbalanced lines, the icon on theReciter Calibration tab indicates that this task is complete.Calibrating the TCXOThe TCXO (temperature compensated crystal oscillator) provides a referencefrequency from which all other RF frequencies are derived.You will need to calibrate the TCXO if you suspect that the reciter (specifically,the transmitter and receiver) is off-frequency. (Off-frequency is defined as beingoutside the range of -1 to +1 ppm.) This may occur for a variety of reasons.Over time the reciter frequency will become less accurate, so it is a good ideato calibrate the TCXO every few years. Exactly how often you do this willdepend on the harshness of the conditions in which the base station is operating.Ideally, you should calibrate the TCXO at a room temperature of 25 ± 5 degreesCelsius. Complete the calibration as quickly as possible since extendedtransmission times increase temperature, which makes the calibration lessaccurate.Equipment Frequency counter RF attenuator (only required if you are using a PA)135 6421 Reciter 3 CTU 5 Unbalanced line input2 25-way cable 4 System interface port 6 Unbalanced line output