For well over fifty years, B&K Precision has served up a variety of low cost test-and-measurement products, most aimed at service technicians, hams, and hobbyists. However, in recent years the company has also offered quite a few lab-grade instruments suitable for mainstream engineering applications. This nomadic spectrum analyzer, in the $10k category, is an example.
With the rollout of the Model 2658 handheld PC-compatible analyzer, the company joins the likes of Willtek, Rohde&Schwarz, Tektronix, Anritsu, Bantam Instruments, Aspen, and others in the portable RF analyzer game. B&K Precision is in the Big Leagues with this instrument with its upper 8.5-GHz spec and its on-board number crunching.
The new analyzer touts a clean and uncluttered front-panel and a crisp LCD, too. The display is a 240 x 320-pixel LCD that can simultaneously display multiple traces as well as instrument settings and measured values, as this sample screen image depicts.
Operationally, you can control the instrument using its rotary encoder, numeric keys, or function keys. You can also control it remotely across its RS-232 serial I/O port.
Performance wise, the 2658's specs are comparable to those of quite a few benchtop spectrum analyzers. Although the 2658 uses a PLL-based (phased locked loop) synthesizer, phase noise is a respectable -90-dBc/Hz (typical at 100-kHz offset). Overall noise is specified at better than -110-dBm, giving the unit good dynamic range as well. Center frequency set-up resolution is 100-kHz.
Options Galore
In its press statement, B&K mentions the availability of optional antennas, cables, and probes, and even a remote printer. These accessories really extend the usefulness of the Model 2658.
A $185 Model 2650 NiMH (nickel metal hydride) battery pack, for example, can provide operation in the field, although it only gives you 100 minutes, if you remember to turn off the unit's internal backlight. I'd like to see a longer run time in the field, but it is what it is. If you're not running in the field, the 2658 is operated from an AC-operated supply.
Antennas, Antennas
You can order no less than six different antenna accessories for use with the analyzer. B&K's Model AN 301, for starters, is a dipole used for making field-strength measurements; it covers 800-MHz to 1-GHz and sells for about $225. The AN 301 is primarily slated for measuring RF in the 800-MHz and 900-MHz cellular bands.
An AN 302 counterpart, also priced at $225, is for the 1.5-GHz band, and an AN 303 dipole serves for W-CDMA and GSM testing in the 1800-MHz and 1900-MHz bands.
Similarly, a $225 AN 304 is for making 2.4-GHz WLAN (wireless local area network) and Bluetooth measurements, and an AN 305, priced at $295, covers the lower 390-MHz through 410-MHz band.
Lastly, B&K offers an AN 306 microwave antenna for applications between 4.7-GHz and 6.2-GHz. It's useful for 802.11a and GPS (Global Positioning System) satellite measurements. It's priced at a bit less than $300.
Click to read antenna comparison table
B&K's press statement mentions a magnetic field probe for measuring chip-level RF. This somewhat pricey Model PR 26M probe will set you back about $3100, but it's capable of precisely measuring the magnetic field distribution on an IC or a printed circuit board.
While electric field strength measurements are good for measuring RF fields of cellphone and WLAN systems, the magnetic field strength measurement capability using the PR 26M makes the 2658 analyzer good for detailed EMI (electromagnetic interference) tests.
It's worthwhile noting that the actual detection portion of the PR 26M probe comprises a shielded loop based on a glass/ceramic multi-layer board. It's what ensures measurement reproducibility by detecting only magnetic field components of a signal. Its measuring range spans 10-MHz to 3-GHz, with the measured value calibrated in the 2658 instrument itself.
Automatic Operations
Not mentioned in B&K's press release is the fact that the Model 2658 is auto-ranging. In use, the analyzer's auto-ranging sets resolution bandwidth, video bandwidth, and sweep-time automatically, with settings based on the set frequency span.
The analyzer also uses automatic tuning, which can be useful if you're probing unknown signals. In this case the center frequency is set at the spectrum of the maximum level. In addition, optimum reference level, video bandwidth, resolution bandwidth, and sweep time are set when you press the instrument's AUTO TUNE key.
One last point: B&K also offers a lower-frequency version of this instrument called the Model 2650. It will let you observe RF spectra from 50-kHz to 3.3-GHz, and is priced at about $4500.
Click here to view the specs for the Model 2658.
For more details, contact B&K Precision Corp., 22820 Savi Ranch Parkway, Yorba Linda, Calif. 92887. Phone: (714) 921-9095, Fax: (714) 921-6422.
B&K Precision, 714-921-9095, www.bkprecision.com
