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Tektronix 1705A
Spectrum Monitor
Tektronix 1705A

Produced from 1988 to 2000+

Manuals – Specifications – Links – Pictures

The Tektronix 1705A is a spectrum monitor designed primarily for locating Ku or C-Band satellites and monitoring their signals with a 3 X 4 in. (80 X 100 mm) monochrome CRT display. It operates by using LNB down converters to the L-Band (950 MHz to 1.8 GHz), and monitoring up link transmissions utilizing an Upconverter to the 70 MHz IF (45 MHz to 100 MHz). The resolution bandwidths 10 kHz and 300 kHz provides measurement resolution proportional to the frequency accuracy or span.

The CRT has a graticule that can be lit up or not depending on the internal jumper position. With non-volatile memory (NVRAM) the current front-panel switch settings can be saved, at power down, so that the 1705A can come back with the last front-panel setup. The user interface has on-screen frequency readout, as well as, setup menus. The L-Band readout may be reconfigured to display a satellite frequency in the range of 0.9 GHz to 20 GHz.

Rear panel inputs/outputs are: L-BAND INPUT F connector (Female connector used for the 900 – 2000 MHz input of the L-Band rf, which is down converted by a Low-Noise Amplifier/Block Down Converted (LNB) from the received satellite signal; The LNB POWER switch enables or disables an 18 V supply for the Block Down Converted through the L-BAND INPUT connector); 70 MHz INPUT BNC connector (Female connector used for the input of the 45MHz – 100 MHz rf).

Specifications based on 2000 published documentation, unless otherwise specified.

Key Specifications

Frequency Ranges L-Band:950 MHz to 1.8 GHz; 70 MHz band: 45 MHz to 100 MHz
Frequency Span Ranges L-Band: Full, 10 MHz/div, 1 MHz/div, and 10 kHz/div; 70 MHz: Full, 1 MHz/div, and 100 kHz/div
Resolution Bandwidth Range -6 dB bandwidth selections are 300 kHz, and 10 kHz
RF Input impedance 75 Ω
Maximum Safe Input Power L-Band: -30 dBm; 70 MHz: -20 dBm
Minimum Signal Input -80 dBm
Video Filter Reduces Video Bandwidth to ≈ 10 kHz
RF Attenuator Range No built-in internal attenuation. Apply an external attenuator to keep the maximum safe input power below the rating listed above
Sweep Speed Range 20 ms to 200ms, variable
Included Accessories Instruction Manual; F-type Male Connector to BNC Female Connector Adapter; and Power Cord
Weight Standard accessories: 3.8 kg (8.5 lbs)
Power 90 − 250 VAC, 48 to 66 Hz, 35 W
Operating Atmospherics Temperatures: 0 °C to +50 °C; Humidity: 95% for five days; Altitude: Up to 4.8 km (15,000 ft)


  • Opt. 74: White CRT Phosphor
  • 1700F00: Plain Cabinet
  • 1700F02: Carrying Case
  • WFM7F05: Side-by-Side Rack Adapter
  • 1700F06: Blank Panel
  • 1700F07: Utility Drawer