Practical field-strength measurements call for an analyzer that is portable yet powerful. The model 3290 RF Field Strength Analyzer from PROTEK Test and Measurement (Allendale, NJ) is a handheld instrument that contains not only a full-featured spectrum analyzer capable of measurements from 100 kHz to 2.9 GHz, but also a sensitive frequency counter, a host of demodulators, and the choice of operating on batteries, AC, or vehicle DC power.
The analyzer (see figure) features a basic data-entry keypad and on-screen menu. The 3290's backlit 192 × 192-pixel liquid-crystal-display (LCD) screen provides a spectrum display or bar graph with large readout of marker frequency and smaller readouts of center frequency, reference level, span, and step size.
Based on a temperature-compensated crystal oscillator (TCXO) and phase-locked-loop (PLL) tuning, the 3290 provides ±3 PPM reference-oscillator frequency accuracy and displayed measurement accuracy of ±25 PPM. The instrument offers 117 dBm sensitivity, handles maximum input voltage of 5 V RMS, and can display levels in units of dBmV, dBµV, or dBm. It features versatile demodulation capabilities with narrowband and wideband frequency-modulation (FM), amplitude-modulation (AM), and single-sideband (SSB) demodulators. In narrowband FM mode, the 3290 operates with a 3-dB bandwidth of approximately 12.5 kHz while in wideband FM mode, the 3-dB measurement bandwidth is approximately 180 kHz. In AM/SSB mode, the 3-dB bandwidth is approximately 2.4 kHz.
Narrowband FM mode detects levels from 70 to 20 dBmV (10 to 40 dBµV) from 300 to 1800 MHz and 60 to 20 dBmV (0 to 40 dBµV) from 1 to 300 MHz and from 1800 to 2900 MHz. Wideband FM mode allows level measurements from 60 to 10 dBmV (0 to 50 dBµV) from 300 to 1800 MHz and 50 to 10 dBmV (10 to 40 dBµV) from 10 to 300 MHz and from 1800 to 2900 MHz. Resolution and level accuracy are 0.5 dB and ±3 dB, respectively, in both modes.
The 3290 analyzer, which is ideal for testing cellular systems, wireless-local-area-network (WLAN) systems, cable-television (CATV) systems, wireless medical-telemetry systems, and satellite-television systems, supports sweeps with step sizes of 5 kHz to 9995 kHz in multiples of 5 and 6.25 kHz. The instrument boasts a scan speed of 125 channels/s. P&A: $2700. PROTEK Test and Measurement, 40 Boroline Rd., Allendale, NJ 07401; (201) 760-9898, FAX: (201) 760-9888, e-mail: firstname.lastname@example.org, Internet: www.protektest.com.