1705A Spectrum Monitor 1-1
Section 1Introduction
The TEKTRONIX 1705A Spectrum Monitoris an 8½”wide by 5¼”high
special purposespectrum analyzer. It weighs approximately8½pounds and is
powered froman ac source. The crt occupies approximately two-thirdsof the
front-panel area, with the control pan el taking up the remainder of the space.
Operation is controlledby a microprocessor that polls the front-panel switches.
Front-panel switchesare of the momentary touch type with lighted functional
indicators. Inaddition to polling the front panel, the microprocessor provides
the charactersfor an alphanumeric crt readout.
The signal is displayedon a bright crt. It is of the mesh type, for better
geometry,and uses an internal graticule to reduce parallax. Variablegraticule
scale illumination provideseven lighting over the usable graticule area to
improve measurement accuracy and the quality of display photographs.
The 1705A Spectrum Monitor is a swept front-end superheterodyne-type
spectrum analyzerwith two inputs; L--Band to accommodate Low-Noise
Amplifier/Block Down Converter(LNB) outputs, and 70 MHz for use with
VideoExciters. The L--Bandinput (950 to 1800 MHz) is through an F-type
connector,while the 70 MHz input is through a standard bnc connector. The
L--BANDINPUT connector is the output for the selectable 18 V supply that is
the Block Down Converterauxiliary power.

TypicalConfigurations

The TEKTRONIX 1705A Spectrum Monitor is designed primarily for use in
locating satellitesand monitoring their signals. It is designed so that it can be
rack mounted, in adual-width rack adapter, along with a half-rack waveform
monitor,such as a TEKTRONIX 1740-Series Waveform/VectorMonitor.
However,it can be used as a portable instrument. It is intended to be connected
to the rf feed with a directional connecto r. See F igure 1-1. It is capable of
providing the dc powerrequired to run an LNB. The auxiliary LNB power is
turned on or offby a rear-panel slide switch. An indicator on therear panel
lights when the +18V supply is operating normally.