Challenges of handheld RF test equipment

In these increasingly challenging times where speed and reliability are virtually everything, radio communication field technicians need portable test tools they can trust.

In the past few years, technicians were happy to live with the relatively basic and dedicated cable and antenna analyser type of device that typically provided measurements such as return loss, VSWR and distance to fault. These were a tremendous step forward over legacy type products such as the classic Bird 43 wattmeter!

In more recent times, and with test equipment evolving, users are now wanting to do more and more with the single handheld unit and are looking at this important tool to combine as many measurements as possible into a very small device.

This is essentially a much smaller and cheaper alternative compared with a radio communications service monitor which can typically weigh 15–20 kg.

The handheld testers need to be rugged to withstand a field environment. Features such as water resistance and tests relating to moisture/dust/shock/vibration and so forth are all important factors to consider. Some handheld devices on offer now have an impressive military category rating (mil-spec).

Another item associated with legacy type products is the mechanical calibration kit, which is traditionally an open/short/load device. This calibration process was regularly performed by technicians whenever a specific frequency band or distance range was changed and was quite often very time consuming and considered a very painful process.

The problem with these mechanical cal kits, besides the time taken to perform the cal, is that there is a lot of wear and tear on connectors and the cal kit can also be dropped, lost or stolen, which means the kit then needs to be replaced.

Modern instruments now include a built-in calibration procedure which allows the user to perform the cal without the use of mechanical components, while still providing extremely high accuracy.

Modern handheld analysers now also allow the user to calibrate across a range of resolution criteria up to 1000 points, which is useful for certain applications where more accuracy is required for a single sweep.

The new internal cal procedure can calibrate across all 1000 measurement points in a few seconds to provide benchtop accuracy in a handheld.

In the past, radio technicians would quite often use cumbersome radio test sets with the spectrum analyser function and tracking generator to tune and align diplexers.

Some of these new field testers have a transmission mode that can be calibrated across a particular frequency band to make fast and extremely accurate two-port filter measurements. The user can quickly identify whether the diplexer is on frequency and then tune and align the filter quickly and accurately.

This capability allows radio technicians to now tune diplexers with a portable handheld device in the field, another task commonly associated with a radio test set.

Radio communications sites are becoming busier and busier with the proximity of co-located transmitters at heavily populated sites. This causes significant ‘ambient RF’ - unwanted signals to potentially interfere with measurement results. Users need to ensure their tools have the highest level of interference immunity to ensure correct results every time.

The new era of field tools has also become smarter in helping the user manage folders so that saved traces can be stored against a logical folder area such as site name, technician name, user name etc. This is especially useful when dragging and dropping files via USB.

In summary, the handheld RF analyser has evolved into an essential tool for field technicians and the latest offerings are doing things smarter, faster and more efficiently than ever before.