2658A BK Precision Spectrum Analyzer


The 2658A is a 8.5 GHz Spectrum Analyzer from BK Precision. A spectrum analyzer measures the power of spectrums of known and unknown signals. Spectrum analyzers collect information such as the magnitude of an input signal compared to its frequency. As a frequency analyzer, spectrum analyzers’ main use is to document and analyze electrical input signals as well as spectral compositions of other signals.

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Additional Features:

  • Frequency range: 50 kHz-8.5 GHz
  • Impressive 4 hour battery life; easy-to-replace rechargeable Lithium-Ion battery
  • Fast sweep speed, minimum 10 ms, to help locate and identify elusive, transient interference signals
  • DANL (displayed average noise level) of -127 dBm
  • Single sideband phase noise – 90 dBc @ 100kHz offset
  • Large easy-to-read color display, 640 x 480 resolution
  • Measurement functions: channel/adjacent channel power, occupied bandwidth, electric and magnetic field strength
  • Convenient Auto tune function
  • USB interface for PC connectivity
  • External trigger for zero span measurements
  • SCPI-like remote control commands
  • Intuitive PC Software for remote control and documentation of measurement results
  • Conveniently store measurement results and screen shots in bitmap format to USB flash drive


  • Installation, maintenance, and troubleshooting of wireless communication systems such as W-CDMA/CDMA, GSM, WLAN, WiMAX and Bluetooth
  • Detection of signal interference and undesired emissions
  • TV and broadcasting
  • Antenna alignment
  • Electric field strength measurement with dipole antennas (order M401-M406)
  • Magnetic field strength measurement with magnetic field probe (order PR 26M)

Included Accessories:

  • User Manual
  • AC Adapter MA400
  • Soft Carrying Case LC2650A, Accessory Pouch
  • PC Software and USB Cable
  • Lithium Battery MB400

The BK Precision 2658A is a compact, light weight and cost-effective spectrum analyzer for quick and precise signal investigations, especially away from the bench. At a weight of only 4 pounds (1.8 kg), the BK Precision 2858A is by far the lightest full-featured spectrum analyzer available, yet it delivers performance and features comparable to a full-size bench spectrum analyzer and can operate up to 4 hours on a single battery.

With its ease of use, measurement flexibility and unmatched portability, this spectrum analyzer is an indispensible tool for engineers and technicians who conduct field measurements in the 50 kHz to 8.5 GHz range.

Versatile measurement functions

Channel power measurement

Allows you to measure the total power or noise power in a user-specified bandwidth.

Adjacent channel power

Measure the ratio of power leakage (from the wanted signal) into adjacent channels. Center frequency, adjacent channel bandwidth, and offset between main carrier and adjacent channels can be set.

Users can select from any of the following three measurement methods based on the reference carrier definition: total power (of displayed spectrum), peak power (reference level) and in-band power (user-specified band width).

Occupied Bandwidth

This measurement calculates the bandwidth containing the total integrated power occupied in a given signal bandwidth. Two measurement methods are available: The user can specify N% of total power or the X dB down point relative to the carrier peak level.

Electric field strength measurement

A dipole antenna (options M401 – M406) connected to the RF input enables the measurement of electric field strength. Users can choose from 6 antennas based on the frequency range under investigation. Each antenna’s resonance point is optimized for the frequency spectrum of a specific wireless standard:

  • M401 is suitable for GSM 850/900
  • M403 for W-CDMA and GSM 1800/1900
  • M404 for 2.4 GHz wireless LAN and Bluetooth
  • M406 for 5 GHz wireless LAN

Combined with the MAX HOLD function and a 10 ms sweep time, the M404 dipole antenna is capable of measuring the electric field strength of Bluetooth systems and systems using direct sequence spread spectrum/frequency hopping modulation techniques.

Using multiple dedicated dipole antennas leads to better measurement results compared to the conventional method of using only a single wide band antenna in which case the frequency range under investigation is typically located far away from the antenna's resonance point, resulting in poor dynamic range. Measuring at or near the resonance point where the antenna gain is at a maximum translates into high dynamic measurement range.

Since the antenna gain factor compensation data is preloaded into the analyzer, the field strength is displayed directly in dBuV/m. The analyzers also support downloading of user-defined gain factor tables for custom antennas.

Magnetic field strength measurement

Using a magnetic field probe (option PR 26M), the 2650A series is capable of accurately measuring the magnetic field distribution on a PCB (printed circuit board) or IC (integrated circuit). The magnetic field strength detector inside the probe consists of a shielded loop structure using a glass ceramic multi-layer board technology with high frequency characteristics.

This enables the detection of magnetic field components only. The probe can measure over a wide frequency range of 10 MHz to 3 GHz. Since the probe’s compensation data is already preloaded into the analyzer, the magnetic field strength is displayed directly in dBuA/m.

Typical applications of this magnetic field probe are evaluation of the effectiveness of a bypass capacitor located near the power supply terminal of an IC or evaluation of the microstrip layout on a PCB. Due to the probe’s high spatial resolution (approximately 0.25 mm), it is not affected by adjacent patterns.

Calculation and Marker functions

Max and Min Hold

Max Hold: At each displayed frequency, the currently-measured value is compared to the previously-measured value and the larger one is retained and displayed. This feature is useful for observing a bursted or intermittent signal or for measuring the electric field strength of systems using direct sequence spread spectrum/frequency hopping modulation techniques.

Min hold: At each displayed frequency, the currently-measured value is compared to the previously-measured value and the smaller one is retained and displayed.

In both cases, the number of sweeps can be set to 2N, where N is from 1 to 10 or infinite.


The analyzer continuously sweeps, then calculates and displays the average value over the total number of sweeps. The number of sweeps can be set to 2N, where N is from 1 to 10. Averaging is useful for detecting signals buried in the noise floor because random noise is averaged out.


The results of each consecutive sweep are displayed and the screen is not cleared after each sweep. This lets you observe the long term variations of a signal.

Marker Function

Two different modes are available for marker measurements:

  • Normal marker mode measures the frequency and level of the marked point
  • Delta marker mode measures the frequency and level differences between the two markers

Peak Function

Two different modes are available for peak search:

  • Normal peak search mode searches for the highest level on the screen. In this mode, you can also use the NEXT button to locate the marker on the next smaller peak.
  • In-zone peak search mode searches for the peak level in the range specified by the center value and width.

Easy operation

The 2650 series handheld spectrum analyzers are straightforward to operate and provide many functions to facilitate quick and easy measurements:

  • Smart one button “Auto Tune" function which automatically scans the full frequency range, detects and centers the maximum signal, and configures optimum values for RBW, VBW, sweep time and reference level
  • Input attenuator and internal preamp are set automatically to optimal values based on the reference level
  • Easy configuration of frequency, span, and amplitude
  • Marker and peak search functions enabling rapid measurements
  • 200 setups and reference spectrum measurements can be stored and recalled from either internal memory or USB flash drive
  • Filenames can be customized and include a date and time stamp.
  • Large easy-to-read display. The backlight is adjustable and monochrome mode can be used for extreme lighting conditions

Long battery life

The 2650A provides a battery operating time of up to 4 hours (approximately 3 ½ hours with back light set to typical settings). Battery replacement is simple and doesn’t require any hand tools. To fully charge the lithium-ion battery takes only approximately 4 hours (analyzer must be turned off). A two color LED indicates the charging status “charging”, “charge completed”, “no battery detected” and “charging error”.

Simple and flexible documentation of your measurements

The 2650A series includes easy-to-use software for documentation and further analysis of your measurements. Connect the analyzer via USB cable to your PC, configure the analyzer remotely, then download measurement data and instrument settings for storage and further analysis.

  • Continuously sweep and transfer trace data to the PC.
  • Capture 1001 trace data points (twice the number of display dots) and store the data in CSV (comma separated values) format for detailed analysis (e.g., import into a spread sheet)
  • Save the screen to a bitmap file or to the clipboard
  • Control all instrument settings from the PC
  • Download custom antenna gain factor compensation data to the instrument

Hardcopy to USB printer

Generate a hard copy of the display by directly connecting the optional USB printer to the 2650A series analyzer.

Conveniently save measurement data to USB flash drive

Easily save and recall measurement data and settings in CSV format directly to and from the USB flash drive. Filenames can be customized and have a time and date stamp. Users can choose to store measurement data and setups in separate files or combined in one file.

Using the Copy function, a screen image in bitmap format (BMP) can be directly stored to the USB drive. CSV data residing in internal memory can be stored to the USB drive in a lump sum.

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