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Agilent Introduces New Power Meter

Agilent's power meters have had a reputation as an industry standard going back to the Hewlett Packard Model 430A, before HP spun off its test and measurement division as Agilent.

Agilent's new power meter, the V3500A Hand-held RF Power Meter, with a list price of $1,800, should appeal to broadcasters who need a reliable way to accurately measure transmitter power, but don't need all the features present in the more expensive Agilent E4416 power meter.

The palm-sized V3500A is Agilent's first handheld power meter. It can be connected to a computer via a mini-USB port for logging. However, unlike the low-cost USB power meters from other manufacturers that only work with a PC (laptop or built into other test gear), the V3500A has a built in display. It can be powered from internal batteries, the USB port, or an AC-DC converter module. Like the larger Agilent power meters, it includes an internal power reference, allowing self calibration but unlike the larger meters, the power sensor is built it.

The V3500A has a dynamic range of -63 dBm to +20 dBm and a frequency range from 10 MHz to 6 GHz. Accuracy is as good as +/- 0.21dB. The V3500A data sheet has complete specifications.

Through the years, I've become much more comfortable depending on accurate, calibrated power meters such as those from Agilent and Rohde and Schwarz for performing transmitter power measurements. The V3500A's low price, one-piece design and ease of operation should make it a fixture at transmitter sites. Long-time readers know that I've preferred calorimetric power measurements with accurate thermometers and a flowmeter as the most reliable way to determine the output power of high-powered TV transmitters. I understand the PWRCAL program that I wrote more than 20 years ago is still being used. However, accuracy is affected by many variables, including heat loss from the load to the surrounding air. Add to that the need to take the transmitter off the air for a measurement and the calibrated coupler and calibrated power meter are an easier, more accurate choice at this price point.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.