Vfo B & Split Frequency Operation - Yaesu FT-990 Operating Manual

Operation Transmitting
D Now, with a non-zero offset displayed, press the
RX
button several times while watching the dis-
play. When the clarifier is activated,
"RX CLAR"
appears near the top center of the display, and
the mair: frequency display shifts by the
amount displayed for the clarifier offset.
D
Press the PIT switch and notice that the trans-
mit frequency remains the same as the original
(that is, non-offset) frequency display when the
receive clarifier is on.
D With the receive clarifier active, turn the
CLAR
knob again, and notice that both the main fre-
quency and the clarifier offset displays change
together.
D Now press the clarifier
CLEAR
key and observe
that the offset is cleared to zero, and the vfo
frequency returns to what it was originally.
The transmit clarifier works almost the same
way as the receive clarifier, by pressing the clarifier
TX
button.
"TX CLAR"
appears near the top center of
the display when active. The offset is added to the
displayed operating frequency, however, only
when you transmit.
A typical application for the clarifier is when
you are in contact with a station whose transmitter
drifts (or perhaps you didn't have him quite tuned
in when you called him). You don't want to change
your transmitting frequency, as that would force
him. to retune - you just want to adjust your
receiVer. You could proceed as follows while listen-
ing to his signal:
D Press the clarifier
CLEAR
button if the displayed
clarifier offset is not zero.
D Then press the clarifier
RX
button to activate the
receiver clarifier, and carefully retune his signal
with the
CLAR
knob.
After you finish your conversation with him,
you must remember to press the clarifier
RX
button
again to turn off the clarifier. However, if you hear
another station you want to call right on the fre-
quency he was on, instead of turning off the clari-
fier, you can just press the
TX
clarifier button to
bring your transmitter onto the same frequency,
and make your call (now both the receive and
transmit frequencies are offset by the displayed
amount). Keep in mind, however, that you will
need to press both the
RX
and
TX
clarifier buttons
again to turn off the clarifier when you finish. You
might also want to clear the offset when done.
The FI-990 actually has an independent clari-
fier for each vfo, on every band, plus one on each
of the 90 memories. This means that clarifier
TX/RX and offset settings are not carried over
page34
when you change bands or memory channels, but
rather are stored until you return to that vfo, band,
or memory again.
Vfo B & Split Frequency Operation
As already mentioned, vfo B works exactly like
vfo A, although each
is
totally independent of the
other. You can use vfo Bas a general-purpose "in-
stant recall" memory, although its primary pur-
pos7 ~s to facilitate split-frequency operation:
receivmg on one vfo (or a memory channel), and
transmitting on the other vfo. The special case of
FM repeater operation uses some features of its
?wn,
a~d
is described in the box on page 33. Also,
~f
the difference
in
transmit and receive frequencies
iS less than 10 kHz, and transmit and receive
modes are the same, using the clarifier functions
just described, is likely to be the easiest approach.'
The four buttons along the bottom of the panel
below the mode buttons are provided to facilitate
setting up the two vfos:
D
A/B
(below the volume control) lets you switch
between vfo A and B, without affecting the con-
tents of either.
D
A=B
copies the contents of the currently dis-
played vfo (A or B) to the other (BorA, respec-
tively), overwriting the contents of the
non-displayed vfo.
D
SPLIT
(below the mode buttons) activates the
"hidden" vfo for transmission. Note that acti-
vating split operation with a memory recalled
uses the last-used vfo for transmission.
D
~VFO
copies the contents of a memory into the
displayed (or last selected) vfo (by pressing it
for %-second). This also overwrites the vfo.
Before activating split operation, you need to
load the vfos with the desired transmit and receive
frequencies and modes. You can set up either vfo
manually (with the mode buttons, band keys and
tuning controls), or you can copy the contents of
previously-stored memories. If you plan to use the
two
vf~s
for split operation, you can check your
transmit frequency by pressing
A/B.
Similarly, if
you
p~an
to
us~
a memory as the receive frequency
m spht operatwn, you can press
VFO/M
to check
your transmit frequency. In either case, press the
same button again to return to the split setup.
. To activate split receive/transmit operation,
JUSt press the
SPLIT
button.
"SPLIT"
appears in a
box at the left edge of the display.
If you are using a separate receive-only an-
tenna, also press the
RX ANT
button.