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> @@ hp - agilent 415E 0-60 db swr analog meter @@
@@ hp - agilent 415E 0-60 db swr analog meter @@
The analog meter movement is a mirrored type where you look for the reflection of your eye's pupil bisected by the needle and thus eliminate parallax in the measurement. There is also a mechanical meter zero pot. The correct way to use this is to turn the pot in one direction so that the needle moves up scale and and then comes back down scale and you stop turning when the needle is over "2" on the expanded scale. If you over shoot, do not turn the screw in the opposite direction, but rather, continue turning and approach the zero position from up scale.
The POWER switch has positions for OFF, ON, (and for instruments with the optional internal battery supply: Battery: ON, TEST and CHARGE). The INPUT switch has positions for XTAL IMPED: HIGH, LOW or BIASED (+1.3 VDC on the center contact with 12.6 mA of current capability) and BOLOMETER: 4.5 mA or 8.7 mA. To match a wide variety of input sources. The HIGH position is also used for signal sources that are not from a detector or power sensor. The INPUT is a BNC(f) connector with the shell 50 Ohms above ground. The FREQ adjust pot allows the center frequency of the 415 to be set to match the frequency of the source generator. The BANDWIDTH control adjusts the width of the passband and therefore also controls the signal/noise ratio for faint input signals. If the 415 is used with a sweeper this control should be set fully CCW to increase the BW to allow for signal variations as the sweep progresses. Also the amplifier output should be used to drive a scope or chart recorder instead of the recorder output since the latter has a low pass filter that limits it's bandwidth. The RANGE-DB control has an outer knob with positions for 0, 10, 20, 30, 40, 50, and 60 dB a very large dynamic range, and an inner EXPAND knob with positions of: NORM, 0, 2, 4, 6 and 8 dB. By using the expanded (red) scale positions you can read amplitude to 0.01 dB over the full 60 dB range. On the 0-NORM range you can bring the needle to full scale with an input signal between 0.120 VAC and ____.
