microHAM SMORF, Manual

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4IN SCREEN
4IN is a very special screen designed to use SMΩRF as a four channel level/phase meter without any sensors.
This screen is available only in special, 4 DIRECT INPUTS meter mode.
The 4IN screen is a big help for low level measurements. Accurate measurements of amplitude and phase on
four inputs simultaneously is unique feature of the SMΩRF you can find only on 4 channel oscilloscopes which
are still not as sensitive and accurate as SMΩRF is, not even the very expensive models.
Thanks to this mode you can measure amplitude and phase distribution of your RF boxes as 4SQ units, stacks,
vertical arrays, splitters, combiners, check antenna stacks or receiving arrays for phasing error or even pass
band characteristic of the filters, preselector or low noise pre-amplifier. There is a lot of applications, just always
keep in mind:
Keep input level below +23dBm on meter's IN RF ports.
CONTROLS:
1.
BAR GRAPHS RANGE
Sets top limit of bar graphs from -30dBm up to +20dBm.
2.
INPUT LEVEL UNITS
Sets input level units to decibels [dBm] or current amplitude ratio [A/A].
3. REFERENCE INPUT
Sets reference input for current amplitude ratio and phase reading.
Screen shows power and phase of the signals directly applied to the SMΩRF's RF IN ports, bypassing external
sensors. Amplitudes are shown at four (4) simultaneously updated horizontal bar graphs, as well as their
numerical values in dBm right next to the bar graphs. Bar graphs have linear 50dB range, maximal value can be
set manually from -30dBm up to +20dBm in decade increments without any impact to numerical values.
Measured amplitudes have no low limit, everything is shown from the noise floor up to the +23dBm, however,
values below -60dBm are not calibrated.
Input level readout can be switched from dBm to the current amplitude ratio A/A, referenced to one of the inputs.
Reference input then displays 1.00, other inputs show amplitude ratio to the reference input.
Phases are shown as vertical bar graphs as well as their numerical values in degrees left to the bar graphs.
Phases display is always referenced to one of the inputs and has logical meaning only if frequency of all input
signals is the same. Please note, phase cannot be measured between IN1/IN3 or IN2/IN4 alone.
It is important to realize that calibration correction factors are applied to input pairs IN1/IN2 and IN3/IN4
separately, and that the SMΩRF needs to know this frequency to show accurate value of input amplitudes.
SMΩRF measures frequency on inputs IN1 and IN3 only, therefore it is important to make sure that the
frequency is locked (F icon on status bar is on). Frequency counter locks at level of about -35dBm and higher,
and remains valid even if later signal level decreases. Frequency lock updates whenever signal level is above
the lock threshold (F icon lights up).
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