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Review: Agilent Technologies U1604A, Part 1 of 2
June 4, 2007

Agilent Technologies U1604A, 40 MHz, price $1651

(click here for the introduction to this series of reviews of four handheld oscilloscopes)

A truly international instrument, the Agilent U1604A (see photo)comes with quick-start guide printed in ten languages. It also comes with a calibration certificate, the only one of the lot to have one.

The U1604A is smaller than the AEMC or Fluke oscilloscopes, but it’s larger than Protek. Buttons are nicely spaced and it has V-mV descriptors for vertical settings and “s TIME ns” descriptors for the time-base button. Its adjustable hand strap is on left side only. On the right side, the instrument has a mini-USB connector for a cable and a USB host connector for inserting a Flash drive (see photo). Oscilloscope BNC connectors are on the top and DMM banana jacks are on the front. BNC connectors are recessed, which makes them harder to get your fingers around the probe connectors to insert and remove. The screen is smaller than those on the AEMC and Fluke oscilloscopes, but it’s big enough to see. Viewing angle is adequate.

The control buttons are arranged around a wheel with channel vertical buttons located on either side of the wheel with time base controls just above (see photo). The unit has separate vertical buttons for the two channels. Channel 1 is red, ch. 2 is blue, which make distinguishing them easy for my color-cling eyes. To turn a channel on or off, you touch that channel’s vertical scale button, which changes the soft keys to function for that channel--not obvious at first, but you get the hang of it quickly.

The center wheel controls settings such as vertical position and trigger level, but it’s hard to spin. It has a depression but it’s not deep enough. The wheel also has “grips” but they’re too small to grab. Protek’s wheel is much easier to spin.

Having just used the Protek, I understood how the Agilent user interface works. You use the SCOPE button when you want to turn a channel on or off, change coupling, or change position. You can use the wheel to select a setting that’s indicated by up/down arrows.

The U1604A uses a proprietary battery pack that contains six 1.2 V, 4500 mAH batteries. It’s easy enough to replace the battery. The cover is located under the stand, held in place by two screws. Fortunately, you don’t have to remove the stand to gain access to the batteries. The AC adapter is small and the power supply separated from the AC mains plug. That’s good for not using more than one plug on a power strip.

The U1604A comes with a blue and a black scope probe, although the unit’s BNC connectors are blue and red. The colors should be consistent. The color difference is in the safety ratings. Blue represents 600 V CAT. III while black is 300 V CAT.III. The quick-start guide gives good instructions on adjusting probe compensation. DMM Probes include insulated alligator clip attachments. Because the BNC connectors are recessed (see photo), I had a difficult time inserting and locking the probe's BNC connectors.

Measurement functions
Pressing the measure button takes you to a menu that includes measurements such as peak-to-peak, RMS, frequency, rise time, and fall time. Holding the button down for two sec enables the cursor function. The Measure button is marked “Cursor to indicate that. You can display up to four measurements. To select a measurement, press the corresponding soft key and use the wheel to scroll through the choices.

Cursor functions are straightforward. You get one or two X and Y cursors for measuring delta V and delta t. You use the wheel to move cursors, which is difficult on the evaluation model I received because the wheel is hard to rotate.

Math functions: Get to Math using the User button, then F3 for Math. Then F1 to turn math on. Choices are DWM and FFT. Set FG to 50 kHz FFT Windows are rectangle, Hamming, Hanning, and Blackman. Again striking similarity to Protek menus and buttons.  DWM direct waveform math) math limited to CH1-CH2, CH2-CH1, and CH1+CH2, same as Protek. It also does average and peak detection. I didn’t see any of the problems with overlapping screen functions that occurred with the Protek oscilloscope.

Triggers: Triggers the same as Protek. Select edge, pulse width, pattern or video. Coupling is AC, DC, HF reject, LF reject. Level: adjust with wheel.

Part 2 will cover the DMM function and the PC software. Go to Part 2.

Posted by Martin Rowe on June 4, 2007 | Comments (2)