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Operation
Transmitting
Transmitting
The IT-890 can transmit within the 500-kHz
segment of the HF amateur bands above 1.8
MHz, and from 28 to 30 MHz. When tuned be-
tween 1.5 and 1.8 MHz, the tuner will not func-
tion, and when tuned to any other (general
coverage) frequency, the transmitter is disabled.
Still, you should restrict your transmissions to
those frequencies authorized by your license,
and for which your antenna is designed.
Attempting to transmit out of band still
causes the red
TX
LED to the right of the meter to
light, but the transmitter will provide no output.
The transmitter is also temporarily inhibited
when stopping scanning (described later), as
pressing the PTT switch while scanning just
causes the scanner to stop.
When you transmit on an amateur band, the
FT-890 senses reflected power at the antenna
jack. If an impedance mismatch causes too much
reflected power, the transmitter shuts down, and
"HI
SWR" appears near the upper left corner of
the display. Although this should prevent dam-
age to the transceiver, we still recommend that
you not transmit without having a proper an-
tenna connected to the antenna jack.
Automatic Antenna Matching
The internal ATU-2 or external FC-800 auto-
matic antenna tuner makes even first-time trans-
mitter setup very simple. After using it once on
a band, it recalls previous settings from memory
(the tuner has 31 of its own) during reception,
whenever you tune to the same part of the band
again. When using the tuner the first time on an
antenna, we recommend you set the
RF PWR
control to around the 9-o'clock position (or 12-
o'clock above 24.5 MHz), to minimize possible
interference to others and to minimize stress on
the tuner, feedline and antenna (in case there is a
high SWR). All you have to do beforehand is
ensure your transmit frequency is clear of other
signals. If you want to monitor the tuner's ac-
tion, press the
SWR
button/LED so it lights.
If
"SPLIT"
is displayed to the left of the he-
quency, press the
SPLIT
button near the top right
to disable split operation for now.
After making sure you are on a valid transmit-
ting frequency, and that the channel is clear of
other signals, press the
START
button near the
upper right corner of the front panel. The green
TUNER
LED comes on, indicating the automatic
tuner is activated,
"WAIT"
appears at the top left
Important!
If the red
HI SWR
LED lights at any time, the tuner
is unable to match your antenna to the transmitter
at the displayed frequency. You will have to tune
to another frequency, or repair or replace your
antenna or feedline.
corner of the display, and the red
TX
LED at the
left end of the display lights for one to about
thirty seconds while the tuner seeks the proper
matching settings.
If monitoring SWR on the meter, you should
see the tuner select the lowest possible reading.
When the
WAlT
indication on the display turns
- .
off, you are ready to transmit (assuming the
HI
SWR
indicator didn't come on).
Once you have used the antenna tuner, the
green
TUNER
LED remains on (unless you press
the
TUNER
button to switch the tuner off). If the
tuner found a match, the
WAlT
indicator will
occasionally flash when you change frequency
(while receiving), as the main microprocessor
reports the frequency change to the tuner
coprocessor (reception is unaffected). The tuner
coprocessor compares the current frequency
with its memories, and resets itself to the new
range if it has any previously stored settings for
that range. However, when you first connect a
new antenna, the tuner does not have the correct
settings stored in these memories, so you need to
"train" the tuner, by pressing the
START
button
whenever you change to a new frequency range
(for this antenna).
SSB Transmission
To transmit in LSB or USB mode:
0
Make sure the appropriate mode indicator to
the left of the tuning knob is lit, and press the
ALC
button/LED so it lights. The meter now
shows automatic level control voltage when
you transmit. This is negative feedback to the
transmitter amplifiers that prevents overdriv-
ing the finals (higher ALC indicates greater
reduction of RF amplification).
0
If this is the first time you are transmitting SSB
with the FT-890, preset the
MIC
control to
about 12 o'clock~ the
RF PWR
control fully
clockwise, and make sure the
VOX
is off
( I ) .
0
Confirm that the display shows the frequency
you want to transmit on.
page
17
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