Following the frequency expansion modification (as specified by Icom), a
sample IC-24 was recently tested for tuning range and input sensitivity
for an S9 signal. While the sensitivity measurements should not be directly
compared with the manufacturer's specifications (usually measured reference
to a signal-to-noise quieting ratio), this "quick and dirty" data should
give you a good idea of the sensitivity to a medium-strength signal.
Tuning Range Mode Band Sensitivity for S9 Signal
74 - 107.995 MHz (fm) VHF range approx 1 mV
108 - 136 MHz (am) VHF range 10 - 30 µV
138 - 240 MHz (fm) VHF range 1 µV - 1 mV (1)
250 - 302 MHz (am) VHF range 50 µV - 1 mV (2)
310 - 354.995 MHz (fm) VHF range 50 µV - 3 uV (2)
355 - 409 MHz (fm) UHF range 3 - 10 µV
417 - 490 MHz (fm) UHF range 1 µV - 100 µV (3)
805 - 955 MHz (fm) UHF range 10 - 100 µV
Notes:
(1) The sensitivity from 138 - 150 MHz was 1 uV. From 150 - 240,
the sensitivity decreased almost linearly from 1 uV to 1 mV
(with input voltage plotted logarithmically).
(2) The sensitivity increased almost linearly for both these ranges
(with input voltage plotted logarithmically).
(3) The sensitivity plot looked like a "U" with the bottom of the
"U" corresponding to the range 440 - 450 MHz (1 uV). The
sensitivity then got worse below 440 and above 450.
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