ImmersionRC RF Power Meter Operator’s Manual October 2013 Edition, Preliminary ImmersionRC | ImmersionRC RF Power Meter 1
Overview The ImmersionRC RF Power Meter is a hand-held, self-contained, RF Power meter, for signals in the 1MHz-8GHz range, with power levels from -50dBm to 0dBm. An external attenuator extends this range to allow the testing of pulsed, and CW transmitters. It has a number of uses, including: - Validation of power levels emitted from CW (continuous wave) downlinks, on 1.2, 2.4, 5.
In order to connect the power meter, with attached attenuator, to an RF source, it is recommended to use either a very short length of coaxial cable, with male SMA on each end, or a short adapter. A suitable semi-rigid cable is included with the RF power meter. HINT: Since SMA connectors are easily damaged by repeated connection/disconnection, it is recommended to connect the attenuator directly to the power meter, and use the SMA adapter to connect to the RF source.
The top button will decrement the frequency; the bottom button will increment it. The center button enters the menu, where the setup of the power meter may be adjusted: Contrast: LCD contrast, not normally necessary to change this, but it the display is difficult to read, it may help to adjust this. Mode: Peak or Avg, use Avg mode for a more precise reading of continuous RF sources, such as A/V transmitters. Use Peak for pulsed sources, such as UHF uplinks, or wireless networking equipment. Mode: dBm or mW.
Examples of Use Example 1: Comparing Antennas This example is relatively simple, two antennas (possibly equivalent antennas from two different vendors) are available, and are to be compared. For this particular example, 5.8GHz omni-directional whips are to be compared. First, setup the transmitter, on a tripod, ideally in an open area without much RF pollution, with few reflective surfaces. A 25mW 5.8GHz transmitter works fine for this. Attach a ‘known good’ 5.8GHz antenna onto the Tx, and power it up.
Example 2: Measuring UHF output power Connect the output of the device to be tested to the power meter, with an appropriate attenuator. For power levels around 500mW, a 30dB attenuator is suitable. For power levels up to 2W, use a 40dB attenuator instead. Enter the menu on the power meter, and enter the attenuator value. If you know precisely (calibrated attenuator), enter the fine attenuation also.
