Important Warnings; Hardware Description - microHAM SMORF Manual

Rf vector signal meter

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2 - IMPORTANT WARNINGS

ALWAYS check the polarity of the 13.8 V power supply

before you connect it to the meter.

If you use meter without sensors,

NEVER exceed 26dBm level to the meter's IN RF ports.

If you use some accessory injecting DC power to the coaxial cable,

connect it ALWAYS behind the LOAD port of any CHF sensor.

DO NOT connect OUT ports to inductive, AC or >24VDC loads.

DO NOT place meter on hot surfaces.

DO NOT touch the sensor under RF power.

ALWAYS backup your settings prior firmware update.

SMΩRF system consists of two parts, sensor and meter.

Sensor is a box, inserted in transmission line (coaxial cable) between source of power (transceiver or power

amplifier) and the load (antenna). Depending on used sensor, it provides sample of current (I) and voltage (U) on

transmission line, or forward (FWD) and reflected (REF) power sample. All HF sensors are U/I type with current

and voltage transformers inside. All VHF/UHF sensors are FWD/REF type directional couplers. All sensors have

internal micro-controller and EEPROM memory for calibration data storage. Micro-controller measures internal

temperature of the coupler and provides these data on request to the meter.

Meter connects to sensor's sample outputs, and measures their magnitude and phase at a rate of 125,000

samples per second as well as internal and sensor temperature. Captured data are than corrected by four

dimensional calibration tables taken during individual calibration for magnitude, phase, frequency and

temperature for both sensor and meter. Meter then further processes the captured data. For some type of

measurements where high data rate is required (alarms, oscilloscope and spectrum screens), raw data are

used. For measurements where stability and smoothness is more important, data are additionally filtered in

various IIR or FIR filters according to their nature. Computed results are than provided on meter's front panel or

computer screen through Ethernet port. Thanks to powerful DSP CPU in the meter and optimized code, meter is

capable to do all above tasks in real time and at the same time provide DDS based tone generator output for

some kind of specific measurements.

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