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Inputs
Parameters
MHz
As displayed on spectrum analyzer / front-end output.
MHz
Set to 0 if you only care about the RF beamwidth. IF = |RF − LO| is shown for reference.
deg
Illumination factor. Typical: 58–80 (70 for uniform, ~65 for typical taper).
meters
Reflector aperture diameter.
Results
Computed Beamwidth
-3 dB Beamwidth
—degrees
Beamwidth (mrad)
—mrad
IF Frequency |RF − LO|
—MHz
Wavelength λ
—mm
D / λ
—
BW (deg) = K × (c / (f × D))
where c = 299,792,458 m/s, f in Hz, D in m
where c = 299,792,458 m/s, f in Hz, D in m
Signal Chain
RF → Antenna → BDC → IF
IF → RF Reverse Calculator
Enter the IF you measured along with the LO of the block converter — get the sky RF frequency and the same beamwidth metrics. Pick the mixing direction (low-side or high-side LO) to disambiguate.
Inputs
Parameters
MHz
Modem-side / post-LNB frequency.
MHz
Same LO as the forward calc.
Pick low-side for Ku/X downlinks, high-side for C-band LNB.
deg
Illumination factor. Typical: 58–80 (70 for uniform, ~65 for typical taper).
meters
Reflector aperture diameter.
Results
Computed Beamwidth
-3 dB Beamwidth
—degrees
Beamwidth (mrad)
—mrad
RF Frequency
—MHz
Wavelength λ
—mm
D / λ
—
RF = LO ± IF (sign set by mixing mode)
BW (deg) = K × (c / (RF × D))
BW (deg) = K × (c / (RF × D))