A 2 GHz Hand-held RF Field Strength Analyzer

Protek
Northvale, NJ

In today's complex world of wireless communications systems it is sometimes necessary to determine a transmitter's radiated field strength in actual field operating conditions. This strategy requires portable testing in the field, which may be among buildings in a city, inside an office or on top of a hill. These measurements must be performed with ease and accuracy but without requiring the operator to drag cumbersome racks of expensive equipment to the location that he or she must spend time setting up and calibrating. The solution to this problem lies in a portable, hand-held instrument that is both user friendly and accurate.

The model 3201 2 GHz RF field analyzer is the first precision portable instrument for RF field strength measurements in the 100 kHz to 2060 MHz frequency range. The instrument is designed for testing, installing and maintaining mobile telecommunications systems, cellular and cordless telephones, citizen band radios, paging systems, and cable television and satellite receiving systems, as well as installing and measuring antennas. The hand-held unit features a phase-locked loop system for precise frequency measurement and tuning, and a built-in frequency counter. The instrument measures narrowband FM (N-FM) and wideband FM (W-FM), AM and single-sideband (SSB) modulated signals. All functions are menu selected. The portable analyzer utilizes internal NiCad rechargeable batteries and is supplied with a battery charger. The screen is a liquid crystal display with a light-emitting diode backlight. A built-in speaker for monitoring the received detected audio signal also is included. An RS232C port is available for PC and printer interface.

The receiver section features a marker frequency accuracy of ±25 ppm over the 100 kHz to 2060 MHz operating band. The operating frequency is stepped in multiples of 5 kHz from 5 to 9995 kHz and in 6.26 kHz steps beyond that range. The instrument features a 10-bank x 160-channel (1600 channel) memory and 10-bank x 160-data memory. The setup memory is 10-bank x three-scan mode. Level measurement capability is -70 to -20 dBmV (N-FM) from 1 to 2060 MHz and -60 to -10 dBmV (W-FM, AM and SSB) from 10 to 2060 MHz. Resolution is ±0.5 dB and accuracy is ±3 dB. The input impedance is 50 W .

The measurement bandwidth is 12.5 kHz for N-FM, 180 kHz for W-FM and 2.4 kHz for AM/SSB. The function display produces multi- and single-bar graph, spectrum analyzer, difference-mode and frequency counter displays. The audio output features a squelch function. Figure 1 shows the instrument's display of a typical FM-modulated 980 MHz carrier. Figure 2 shows a frequency scan of the analog cellular telephone band.

In the frequency counter mode, the frequency range is 9 to 2060 MHz with a 1 kHz resolution and an accuracy of ±50 ppm ±1 count. The counter's response time is 0.512 seconds. Input sensitivity is 120 mV RMS over the 9 to 2060 MHz range, 50 mV from 20 to 1500 MHz and 500 mV from 2 to 2600 MHz. Input impedance is 50 W . The data memory stores 10 channels.

The unit can be powered from an 11 to 16 V DC external source and draws 400 mA (max). A user-selectable auto power-off function turns the power off automatically five, 10, 20 or 30 minutes after the final key operation. The analyzer is designed for operation from 0° to 40°C to 85 percent humidity, and weighs approximately 1.4 lb. Case dimensions are 9.00" x 4.00" x 1.77".

The instrument is supplied with PC interface software, an external antenna, a carrying case, a RS232C cable, six AA NiCad rechargeable batteries, an operating manual, a car adapter and an AC adapter. Optional accessories include the model PR-232 mini printer. The model 3201 2 GHz RF field strength analyzer is priced at $2100 (including battery charger) and is available from stock. Additional information about the analyzer can be obtained from the company's Web site at http://www.hcprotek.com.

Protek,
Northvale, NJ
(201) 767-7242.