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Spectrum Monitor

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Features & Benefits

  • Full 850 MHz Span for International Satellites
  • L-Band and 70 MHz IF Inputs
  • Designed for Satellite News Gathering
  • Easy, Reliable Operation
  • Cost-effective
  • On-screen Ku- or C-band Frequency Readout
  • On-screen Setup Menu
  • Selectable 2 dB/div or 10 dB/div Sensitivity
  • Resolution Bandwidth Switchable to 10 kHz or 300 kHz
  • Span Range and Video Filter Selection
  • Bright, Clear Display


  • Identification of Satellites/Transponders in OB Vans
  • Monitor Satellite Spectrum at Downlink Facilities

1705A menu flow.

The 1705A is a compact, specialized spectrum monitor designed for operators of portable television earth stations to adjust transmission equipment and to correctly access geostationary satellites operated by public and private communications organizations. The 1705A offers expanded capabilities for observing the 850 MHz wide frequency band used by international satellite carriers.

Dual Band Operation

Separate signal inputs allow connection to the two primary signals of interest in a television uplink/downlink system. A 45-100 MHz band allows observation of the television exciter at the 70 MHz IF monitoring point for a check of video deviation and aural subcarrier injection. A 950-1800 MHz band, with a separate RF input, allows observation of the full satellite downlink spectrum as down converted by the antenna-mounted, low-noise block down converter (not supplied). The input levels available in typical satellite television systems match the input sensitivity of the 1705A without need for operator adjustable input attenuators.

In addition to a span of the full spectrum in each band, the 1705A allows a selection of narrow spans and resolution filters for observation of individual satellite transponders, the video FM modulation envelope, or associated audio carriers.

Using the 1705A, the operator can quickly identify the assigned satellite and transponder and correctly adjust the direction and polarization of the portable uplink/downlink antenna. Precise antenna pointing is facilitated by a selectable 2 dB or 10 dB per major division vertical screen sensitivity with vertical position control.

Compact Size

The 1705A is unique in size, shape and utility. 8.5 in. (215.9 mm) wide and 5.25 in. (133.4 mm) high, it fits into a standard Tektronix dual half-rack WFM7F05 Option OO cabinet, along with a matching 1700 Series waveform, vector or combination monitor.

Microprocessor Control

A menu selected readout offset allows on-screen indication of the Ku-band or C-band satellite operating frequency in steps of 10 MHz. The offset may be set for local oscillators operating above or below the received signal. The status of all front panel buttons is stored when power is removed and all modes are restored on power-up, ready for quick operation. Function indicators are lighted for visibility in television operating environments.

RF Spectrum Display

Span per division, resolution bandwidth and display video bandwidth may be selected for full satellite, transponder or discrete carrier display. The band of interest is highlighted in the full span mode, with frequency indicated as an alphanumeric readout. In 10 MHz, 1 MHz and 100 kHz span/div modes, the readout indicates the frequency of the spectrum displayed directly under the cursor.

A CENTER FREQUENCY control marks the display in full span and moves the spectral view through the entire selected band in narrower spans.


1705A Rear Panel.

Bright, Full Size CRT Display

The signal is displayed on a bright, mesh type CRT with internal graticule to eliminate parallax. Variable graticule illumination improves readability under difficult conditions. The display is a full 8x10 cm and the bezel accepts camera and viewing hood options designed for Tektronix 1700 Series monitors.

Designed for Rugged Use

The 1705A spectrum monitor is designed to provide reliable operation in portable news gathering applications. The 1705A is built to withstand extremes of temperature, altitude and vibration. Its small size provides a freedom of system design critical in the rapidly changing television news environment.


Frequency Range -

L-Band: 900-2000 MHz (F-type connector), with performance specified over a range of 950-1800 MHz.

70 MHz: 45-100 MHz (BNC type connector).

Frequency Span -

L-Band: Full (900-2000 MHz with 1000 MHz on screen), 10 MHz/div., 1 MHz/div., 100 kHz/div.

70 MHz: Full (45-100 MHz with 50 MHz on-screen), 1 MHz/div., 100 kHz/div.

Frequency Readout - Alphanumeric on-screen display with center frequency marker. Offset may be adjusted to read satellite frequency in range of 0.9 GHz to 20.0 GHz.

Readout Accuracy - ±10 MHz.

Frequency Marker -

Full Span: Bright up marker at indicated frequency. Marked frequency will be on screen in next narrower span.

MHz/div. Spans: Selected center frequency indicated by caret marker.

Span/Div Accuracy -

L-Band: Full span typically 0.5 minor division.

70 MHz: Full span typically 1.0 minor division.

Relative Amplitude Accuracy - Typically ±1 dB/100 MHz over L-Band frequency range of 950-1800 MHz.

Display Sensitivity - Nominally 10 dB or 2 dB/div.

Flatness - L-Band (950-1800 MHz) ±5 dB; 70 MHz (45-100 MHz) ±2 dB.

Positioning Range -

Vertical: ±3 divisions.

Horizontal: ±2 divisions.

Resolution Bandwidth - Filter Bandwidth: 6 dB down 10 kHz or 300 kHz.

Maximum Input Signal Level -

L-Band: -30 dBm, 75 Ω.

70 MHz: -20 dBm, 75 Ω.

Video Filter - Reduces display video bandwidth to approximately 10 kHz.

Low Noise Blockconverter (LNB) DC Supply - +18 V DC ±5%, 250 mA max output through L-Band input connector, switched on/off by rear panel slide switch LED indicator on rear panel.

CRT Display

CRT Viewing Area - 80x100 mm.

Accelerating Potential - 13.75 kV.

Trace Rotation Range - >±1 degree from horizontal. Total range typically 8 degrees.

Graticule - Internal, 8x10 division spectrum monitor graticule with variable scale illumination.

Power Source

Mains Voltage Ranges -

110 V: 90-132 V, 100-132 V with LNB supply switched on.

220 V: 180-250 V, 200-250 V with LNB supply switched on.

Mains Frequency Range - 48 Hz to 66 Hz.

Power Consumption - 25 W, 35 W maximum with LNB supply switched on.


Temperature -

Nonoperating: -55°C to +75°C.

Operating: 0°C to +50°C.

Altitude -

Nonoperating: To 15,240 m (50,000 ft.).

Operating: To 4,572 m (15,000 ft.).

Shock - Nonoperating: 30 gs, 1/2 sine, 11 ms duration, 3 shocks per surface (18 total).

Vibration - Operating: 15 minutes each axis at 0.015 in. (frequency varied from cycles with instrument secured to vibration platform) 10 minutes each axis at any resonant point or at 55 Hz if no resonant point is found.

Transportation - Qualified under NSTC Test Procedure 1A, Category II (30 in. drop).


EMC - Certified to the EMC Directive 89/336/EEC.

Safety -

Approved to: UL1244, CSA231.

Complies with: EN61010-1, IEC61010-1.

Physical Characteristics



















Ordering Information


Spectrum Monitor.

When ordering, please use the nomenclature given here. The standard instrument is shipped without a case or handle. If your application is for bench or portable use, please order the appropriate enclosure from the optional accessories list. The 1705A is a UL-recognized component and meets the requirements for listing when used in the appropriate enclosure.

Includes: Instruction manual, adapter, F-type male connector to BNC female connector, power cord (with correct plug for the selected power plug option). Please specify power plug when ordering

1705A Options

Opt. 74 - Substitutes white phosphor CRT.

Power Plug Options

Opt. A0 - US Plug, 115 V, 60 Hz.

Opt. A1 - Euro Plug, 220 V, 50 Hz.

Opt. A2 - UK Plug, 240 V, 50 Hz.

Opt. A3 - Australian Plug, 240 V, 50 Hz.

Opt. A5 - Swiss Plug, 220 V, 50 Hz.

Opt. AC - China Plug, 50 Hz.

Opt. A99 - No Power Cord.

Optional Accessories

1700F00 - Plain Cabinet.

1700F02 - Portable Cabinet.

WFM7F05 Option OO - Rack Adapter.

1700F06 - Blank Panel.

1700F07 - Utility Drawer.

016–0475–00 - Viewing Hood.

200-3897-01 - Front Panel Cover.

Support Options

Contact your local Tektronix representative.