The MSA438 is a capable spect-rum analyser in a compact package. Its 14cm (5.7”) 640x480 pixel LCD displays a clear and uncluttered frequency domain plot and it is controlled using 22 pushbuttons and a jog wheel.
The unit weighs 1.8kg so it can be operated hand-held – even with one hand, although we wouldn’t want to hold it like that all day. It’s 162 x 265 x 71mm which is large for a hand-held instrument but manageable enough. There is a fold-out stand on the back for desk-top use.
The unit is easy to drive and it only takes a few minutes to get the hang of its interface, which like many instruments these days is based on a set of six “soft buttons” below the LCD. There is also a numeric keypad for quick frequency entry or you can use the jog wheel for fine adjustments.
The signal input is an N-connector (50Ω) and there is also an SMA input for external triggering.
It has an “auto tune” mode, but this will not make you a pop music sensation! Rather, it searches for the strongest signal in the current frequency span and sets the unit up to focus on it. In manual mode, you can have it automatically adjust parameters such as resolution bandwidth (RBW), sweep time and so on or you can specify them yourself.
The unit has two USB sockets. One is for a flash drive, which can be used to store screenshots, captured data (as comma-separated variables) and configuration data. The other connects to a computer and in combination with software sold separately, can be used to drive the unit. With a computer, you can get a higher resolution spectrum, 1000 pixels wide rather than 500.
With the optional battery, operating time is stated as four hours but that’s with the LCD backlight off which is only useful if it’s plugged into a computer. With the backlight on, battery life is more like 2-3 hours.
When it runs low, you get a series of increasingly urgent warning beeps before the unit cuts out.
One quirk of the MSA438 is that you can’t charge the battery while using the unit. Presumably that’s because the mains adaptor “brick” doesn’t have the herbs.