What we know re CM7775 (UHF Only part of OLD CM7777):
Specs: UHF Gain = 26 dB, NF=2.0. [See PREAMP OVERLOAD CALCULATOR Spread Sheet for Overload Specs.]
Per SPECS, I calculated UHF Max Input of -35.8 dBm for Two Strong Signals and Max SFDR = 55.0 dB
CM7775 + OLD CM7777 NOT tested by either Calaveras or ADTech for Overload.
What we know re AP8780 (UHF Only part of AP4800):
Specs UHF Gain = 28 dB, NF=2.7. [See PREAMP OVERLOAD CALCULATOR Spread Sheet for Overload Specs.]
Per SPECS, I calculated UHF Max Input of -28.8 dBm for Two Strong Signals and Max SFDR = 62.0 dB
AP8780 + AP4800 NOT tested by either Calaveras or ADTech for Overload.
So, PER THE SPECS, AP8780 has 5 dB Wider SFDR and can Tolerate a 7 dB Higher Max Input Signal Strength.
PS: Spurious Free Dynamic Range = Difference between Strongest Carrier Level and Thermal Noise Floor when Input Level is Adjusted for Max Dynamic Range wherein the InterMod Distortion Noise is just barely BELOW the Thermal Noise Floor (about -106 dBm). Note that some INPUT ATTENUATION may be required in severe Overload situations in order to bring the signals within the Max Input Signal Level, since IMD is reduced by 3 dB for each 1 dB of Input Loss, hence 6 dB Input Loss reduces IMB by 18 dB, a NET Improvement of 12 dB.
BTW: NEITHER of these comes even close to the Overload Resistance of fol. Mast Mounted Preamps: A-D Juice (SFDR=82.5 dB) and HDP-269 (SFDR=85.7 dB
, Spec Calcs claim 71.3 dB, only 15 dB Gain only suitable for LOW LOSS Systems) or the fol. inexpensive DistroAmp: CM3410 (SFDR=81.9 dB)
....where the extra Input Coax Loss MIGHT actually be HELPING to reduce InterMod Noise Levels.
Calaveras Comparisons of MEASUREMENTS:
Comparisons of OLD PREAMP Specs: [I added last two columns, re-normalized for TWO Strong Input Signals.]
My OLD PREAMP OVERLOAD CALCULATOR SPREAD SHEET: [Pick *.PDF if you only want to LOOK at it.]
XLS 9 of 25, OTA Reception Files
Note that in the Overload Calculator S/S, I advise keeping Input to Tuner (Sih) less than -10 dBm and preferable less than -15 dBm....a educated guesstimate, since Tuner mfr's NEVER divulge this important piece of information. And NOTE that the + 5 dBm SINGLE SIGNAL Overload Number found in CECB Requirements Spec is DIFFERENT, measuring when the Amp goes into SATURATION, no longer passing ANY Signals....whereas we are far more interested in the INTERMOD Interference, which is a TWO or THREE Strong Input Signal Test that DEGRADES Sensitivity for Reception of WEAK Signals.