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Unaohm S48+ Spectrum Analyzer

The Unaohm S48+ is a DVB-S / DVB-S2 satellite spectrum analyzer with NIT & Satellite ID capability.

The S48+ is a DVB-S and DVB-S2 spectrum analyzer featuring an "Automatic Satellite Locator" (ASL) function, which allows users to easily identify satellites.

This outstanding feature lets the installer operate the instrument hands-free, until the dish is coarsely aligned on the correct satellite. Once the satellite has been identified, normal level-based adjustment can used for accurate/fine antenna peaking.

The ASL function consists of a sophisticated identification algorithm, by which the spectral signature of a chosen satellite is compared to the spectral signature received by the instrument. When the signatures match, the instrument confirms the correct position of the dish! Up to 20 spectral signatures can be stored in the instrument by the user. As satellites and signatures change, the user can update his satellite definitions via the click of a button.

In addition to the ASL function, the S48+ features a "Network Information Table" (NIT) card that allows the user to list the contents of any VIDEO/AUDIO Mpeg-2 DVB carrier.

The NIT function is available BER mode, where you can punch in the Symbol Rate of the transponder to analyze it and retrieve NIT information, which will also provide satellite identification, orbital position and a list of the services available.

This instrument is manufactured by Unaohm.

You can download Unaohm's spec sheet (in PDF format) and the instruction manual. We have also posted an example of on field use with the S48+/48+.

Buy!the Unaohm S48+ online.

Unaohm S48


Quality is one of Unaohm's trademarks. All instruments are made in Italy and must go through individual quality control before being released on the market. The components used inside and outside each instrument guarantee years of service without any or very little maintenance.

Durability wise, the sturdy case of the S48 is further protected against falls and blows by a thick rubber holster. The weatherproof keyboard and the RF input connector have also been designed for construction site environment , where hostile elements such as dust and humidity are present.

When it comes to accuracy, Unaohm only incorporates the best RF components in its instruments. Furthermore, each S48 is individually calibrated to ensure accurate level and frequency readout. Frequencies on the S48 can be selected with 0.1MHz precision and the level readout is available with 0.1dB accuracy in analogue and digital mode.

If you are new at satellite installation, this instrument also comes with our acclaimed booklet: Locating and Peaking Satellites with a Spectrum Analyzer. We will also provide you with a list of frequencies and symbol rates for each North American satellite, allowing you to lock in almost anything without spending more time than you should looking for a signal (this list is updated every quarter).

Other standard features of this instrument include:

  • Log capabilities of up to 1500 acquisitions.
  • Satellite identification.
  • Cumulative count of errors over time.
  • Hold mode (MIN or MAX) to catch sporadic signal presence or interference.
  • DiSEqC 1.1 and 1.2 protocols (preset and user configurable functions).
  • Aural tone in MEAsurement mode with higher tone pitch when the signal gets stronger.
  • Automatic and Manual attenuation modes.
  • Histogram representation (DLPrg) of 1 to 27 user-defined frequencies.
  • Tilt function in DLPrg mode to compare max and min levels along with level delta.
  • Up to four user-defined L/O frequencies for direct satellite frequency readout.
  • User-defined level measurement unit (dBm, dB or dBµV).
  • RS232 interface to preset or extract program information.
  • Printer interface with logo (installer or company name) to printout results on the field or back at the office.


Level and Frequency Range:

  • 40 to 120 dBµV from 920 to 2150 MHz (Analogue SAT and 1 MHz BW digital level).
  • 44 to 124 dBµV from 920 to 2150 MHz (30 MHz BW digital level).
  • Aural tone proportional to signal level.

Unit of Measure:

  • dB for ratio (relative) measures.
  • dBµV - dBmV - dBm (user-defined) for level and power measures.


  • 0 to 50 dB in 10 dB steps. Manually selectable or automatic.
  • Accuracy: ± 2dB.

Measure and frequency readout:

  • Numerical level readout with 0.1dB resolution.
  • Numerical frequency readout with 0.1dB resolution.
  • Analogue through the MEAsure signal bar or in DLPrg mode.

Measurement Bandwidth (RBW):

  • 5 MHz @ -3dB.

Input Impedance:

  • 75 ohm unbalanced.
  • 50 ohm input impedance available as a special feature.

Input Connector:

  • Female “F” connector with a protective L-shaped adapter.

Maximum Applicable Voltage:

  • ± 100 Vdc and 5 Vpp RF.

LCD Indication:

  • Numeric for level, four digit, 0.1 dB resolution.
  • Numeric for DCP, four digit, 0.1 dB resolution.
  • Analogue by means of a bargraph.
  • Analogue by means of a histogram.

Frequency Range:

  • 920 to 2150 MHz.
  • ± 2 dB accuracy throughout the entire frequency range.

Tuning Selection:

  • By frequency. Continuous PLL frequency synthesis in 125 kHz steps.
  • By program. Recall of any program out of those stored, up to 100.

Frequency Reading:

  • Frequency reading is rounded off to the nearest 100 kHz in IF mode and to the nearest MHz in L.O. mode.

Spectrum display:

  • Spectrum (full and expanded). 200, 100, 50, 20, 10 MHz expansion steps from 920 to 2150 MHz.
  • Histogram mode. Up to 28 user-defined-program.
  • Hold max, Hold min, Freeze.
  • Two independent markers for frequency and level reading; reading of differences between markers on LCD readout.

Data Logger:

  • Approximately 1500 single program data-captures (acquisitions).

Digital Analysis:

  • DVB-S (QPSK) and DVB-S2 (QPSK & 8PSK)
  • Symbol Rate: 1.45 to 36 MS/s (1.0 to 42 typical).
  • Code Rate: Automatic.
  • Spectrum Polarity: Automatic.
  • Constant "LOCKED" or "UNLOCKED" indication on the LCD readout.
  • CH BER Measurement: 0 to 1. 210-7 resolution.
  • CH BER Display: Numeric, in exponential notation) and analogue, via a bargraph.
  • Post Viterbi BER Measurement: 0 to 5*10-2 to 2*10-8 resolution. Numeric reading.
  • MER: 5 to 20 dB. Numeric reading.
  • RU count: Count of uncorrected errors past the Reed Solomon algorithm (up to 65535 errors).
  • Relative power index: LOw, OK and HIgh for low, correct and high level.
  • CFO: Shows the offset from nominal center frequency in MHz.

NIT Card:

  • Provides NIT information when correct frequency & symbol rate is provided for any given Mpeg-2 DVB transponder modulated in QPSK.

Power Inputs & Outputs:

  • 0; 13 and 18 V ± 0.5V user-selectable. 350 mA max current.
  • Overload warning indication and continuity of external circuit provided.
  • 22 kHz ± 1 kHz / 0.6 Vpp tone. Square wave.
  • DiSEqC 1.1 and 1.2 (for steerable dishes) protocols.

LCD Readout:

  • Backlit (switchable) 128 x 64 dot matrix graphic LCD readout. 71 x 39 mm.

RS232 Serial Port:

  • Female 9 pin “D” type socket for data exchange to a PC, serial printer, modem.


  • Internal Vdc Power: 6 V/ 3.8Ah Ni-MH rechargeable battery pack. 11/2 hours continuous operational run (when current draw to LNB is 100 mA max.).
  • External Vdc Power
    • 7.5 to 8 V / 3 A max for operation and battery charge.
    • 5.5 to 8 V / 3 A for operation only.
  • Mains: 100 to 240 Vac through an external power supply/charger unit, provided.
  • Battery Charger: Through external power supply/charger unit, provided.
  • Full battery charge time: 8 hours.


  • Dimensions: 200x105x45 (7.8”X4.1”X1.7“) mm, WxHxD.
  • Weight: 0.9 kg with battery pack and holster included.
  • Finishing: The unit comes with a sturdy antishock protective rubber holster.

Ambient & Calibration:

  • Calibrating Temperature: Tolerance quoted refers to an ambient temperature @ 23 °C ± 5 °C.
  • Operating Temperature: 5 °C to + 40 °C.
  • Relative Humidity: 80 % for a temperature up to 31 °C (linear derating to 50 % @ 40 °C).
  • Storing Temperature: -10 °C to +60 °C.

Standard Accessories:

  • L-shaped F/F input adapter.
  • Rubber holster.
  • Neck and transport strap.
  • Instruction Manual.
  • Power Supply/Charger Unit BCH 7.5/3.3
  • Internal 6 V / 3.8 Ah Ni-MH battery pack.

Optional Accessories:

  • Spare waistband-held battery pack BP6.
  • Nylon bag for transport C20.


The Unaohm S48 fits in your hand (S22 shown)

Backlit LCD screen provides perfect visibility in sunlight or in darkness (S22 shown)