Base-station test module developed for field technicians

Ever gotten a call from one of your big corporate customers complaining that no one can make calls in its office building? If so, chances are your approach was to track down a spectrum analyzer and haul it around the building, trying to find out why the signals weren’t getting through.

“The problem is that (spectrum analyzers) are big, expensive and, because of the number of cell-site technicians, operators usually have only three or four that have to be shared,” said David Newman, Acterna (www.acterna.com) director of product management.

Acterna’s portable RF and base-station tester is designed to remedy these problems. The TestPad BAT (Base Station and Air Interface Test Module) launched this week in conjunction with the PCIA and Wireless IT trade shows.

“The concept was to develop a unit that is hand-held and low cost so every cell-site technician can have one,” Newman said, pointing out that with the telecom industry pushing to increase the number of base stations per technician, it’s good to have equipment there when you need it and not have to share it.

Rather than starting from scratch, Acterna took its existing test-tool module complete with user-interface screen and software, and then created different modules for different applications that unplug from the main unit. These include landline testing of copper and fiber. The RF module allows techs to test various RF components at the base station. For example it can monitor power levels for each of the radios, see what the radios are transmitting and adjust them as needed. It is also possible to look at the reflected power coming back through the antenna and the cable.

“As long as the ratio is fairly high, the antenna is in good shape,” Newman said. “If it’s low, there is a problem.”

He said many test pads with T1 test modules are already in the field in the United States. The RF module was developed so that technicians familiar with the T1 tests can do the RF tests easily.

In one test, the technician can load the BAT with the configuration of a cell site that has all the radios, the expected power levels and frequencies and the tolerances or thresholds that are considered “passing.” The tech then hooks up the unit, it makes tests, and the results are either pass or fail.

“If it’s fail, we can capture the screen, enter notes, and then we can send it back to the central office or keep the file on site,” Newman said. Each unit has two flash cards for memory in order to keep a record of ongoing tests.

An advantage is that the scanning does not involve taking the cell site out of operation. In previous situations, testing involved physically disconnecting the antenna, so a carrier would have to do it in the middle of the night to keep customers from being affected. The TestPad BAT works for AMPS, CDMA, GSM/GPRS and TDMA networks and will be operational on UMTS as that technology is more widely deployed.

Zeus Kerravala, Yankee Group (www.yankeegroup.com) analyst who was briefed on the product, used to be a frame engineer. He remembers working with technicians who would spend about an hour trying to fix something and finally go back to the truck, get their T-Berd analyzers and fix it in ten minutes. When he’d ask why they didn’t bring the T-Berd in the first place, they’d say that it was big and cumbersome and they thought they could fix the without the instrument.

Making the tool more available and easier to use should result in a dramatic reduction in the testing time for technicians who are typically overworked, Kerravala said.

Acterna’s TestPad 2000 Base Station and Air Interface Test Module is battery-powered and hand-held, weighing about 10 pounds. The RF module is located to the right of the screen and can be changed out with modules for wireline testing.