Dual Vfo's - Icom IC-25A Instruction Manual

144MHz ЕМ TRANSCEIVER INCORPORATING A MICROCOMPUTER
CPU control with ICOM's original programs provide various operating capabilities. No-backlash
dial controlled by ICOM's unique rotary encoder circuit. The band-edge detector and Endless
| System provides out-of-band protection. There are no variable capacitors or dial gear, ensuring
problem-free use. The IC-25A/E can accomodate FM, coverage in the 144 ~ 146MHz (IC-25A:
143.8 ~ 148.2MHz) frequency range.
MULTI-PURPOSE SCANNING
The Memory Scan allows you to monitor five different memory channels and two VFO frequencies,
and the Program Scan provides scanning between two programmed frequencies. The scanning
speed is adjustable, and the auto-stop terminates scanning when a signal is received or a channel is
empty.
DUAL VFO'S
Two separate V FO's can be used independently either for simplex operation or for duplex opera-
tion, and any desired frequency can be split in duplex operation.
CONTINUOUS TUNING SYSTEM
ICOM's new continuous tuning system features an LED display that follows the tuning knob
movement and provides an extremely accurate readout. Frequencies are displayed in 4 LED digits
representing 5KHz digits.
Automatic recycling restarts tuning at the top of the band, i.e., at 145.995MHz when the dial goes
below 144.000MHz. Recycling changes 145.995MHz to 144.000MHz as well. Quick tuning in
25KHz steps (IC-25A : 15KHz) is available with VFO "B", and is also provided for trouble free
QSO (1C-25A : 145.995MHz and 144.000M Hz should be read 148.195MHz and 143.800M Hz.)
OUTSTANDING PERFORMANCE
The RF amplifier using a MOS FET and the first mixer using a double balanced mixer, and other
circuits provide excellent cross modulation and two-signal selectivity characteristics. The IC-25A/E
has excellent sensitivity demanded especially for mobile operation, high stability, and with a pair
of high quality monolithic crystal filters and ceramic filters facilitates very stable receiving and
excellent durability.
The transmitter uses the double balanced mixer (the same one for receiver) in a single conversion
system, a band-pass filter and a high-performance low-pass filter. This system provides distortion-
free signals with a minimum spurious radiation level.
The IC-25A/E has everything you need to truely enjoy VHF FM operation, in an extremely com-
pact, rugged transceiver, designed to ensure high quality, long term use.