switches on +28v battery power (+28w On), via the
Battery power is low.
volume control, for use )by various modules.
A tune fault condition exists.
3-11. YNTHESIZER. The synthesizer generates 5
An antenna tune cycle is in progress.
MHz, 70 or 80 MHz, and 77 thru 105 MHz LO signals.
These LOs are used by the modulator/demodulator to
3-13. POWER AMPLIFIER. During transmit operation,
produce the radio frequency in Xmt, or demodulate rf in
Rcv. If the operator selects LSB, 80 NMHz is routed to
the power amplifier boosts the Xmt RF from the
the modulator/demodulator. If USB is selected, 70 M1Hz
modulator/demodulator to 20 watts. In receive operation,
is chosen Frequency Select signals from the control
the amplification circuits are bypassed. In Xmt, rf is then
panel determine the frequency between 77 and 105
routed to the harmonic filter.
Which goes to the modulator/ demodulator A IkHz
signal is routed to the modulator/demodulator for use in
3-14. HARMONIC FILTER.
The harmonic filter
fault indication signals and cw operation.
removes undesirable spurious signals during Rcv and
The specific filter
frequency range is determined by the Frequency Select
modulator/demodulator converts the voice or cw (Xmt
signal from the control panel. The Xmt/Rcv RF path to
Audio) to two intermediate frequencies (if.) and the radio
the antenna tuner is the same for both.
frequency (Xmt RF). It uses the 5 , 70 or 80 MHz and 77
thru 105 NMHz LO signals from the synthesizer for this
3-15. ANTENNA TUNER. The antenna tuner
purpose. In receive operation, the same circuits extract
automatically matches antenna impedance to the radio
the voice or cw (Rcv Audio) from the receive radio
set at the selected frequency.
modulator/demodulator contains alarm generator circuits
3-16. POWER SUPPLY. +28v On from the control
which produce audio signals to alert the operator as
panel is routed to the power supply. It produces and
distributes regulated +6.5v and +12.5v to the other