Yaesu FT-757GX Operating Manual page 31

Set the VOX switch on the front panel to the
depressed position. Set the KEYER switch on
the top panel to the MAN p osition, and close the
key or press the dot paddle to transmit a carrier (if
using an external keyer it will be necessary to short
the output keying line). Now adjust the DRIVE
control to obtain slight ALC deflection on the
meter (for full power output).
If using keyer paddles and the internal keyer, set
the KEYER switch on the top panel to AUTO, and
adjust the SPEED control for the desired keying
speed .
The sidetone volume during CW transmission can
be adjusted using a small screwdriver. The control
for this purpose is accessible through the hole near
the rear of the bottom cover.
With the VOX button depressed, semi break-in
operation is selected.
linear amplifier, only semi break-in operation
should be used. The hang time (between the
moment that the key opens and receiver activation)
can be adj usted using the DELAY control on the
rear panel (this also controls the VOX delay during
voice operation). If the VOX button is not pressed
and the BREAK-IN switch is set to SEMI the
sidetone will be heard when the key is closed , but
no transmission will occur. This feature can be
useful for zeroing in on received signals (by match­
ing the received signal pitch to the sidetone), and
for CW practice. For QSK operation, set the
B REAK-IN switch on the top cover to FULL, and
the VOX button on the front panel to the un­
depressed (out) position.
During split-frequency Q SK operation, the receiver
will automatically provide a brief check of the
transmit frequency before
intended rece1vmg
operator to maintain awareness of activity on both
frequencies.
Note : The FT-7 5 7GX is capable of high-speed
split-frequency Q SK operation only when
both (RX and TX) frequencies are within
the same (500 kHz ) band.
between wider-spaced frequencies is limited
to a slower speed, because of the necessary
ex tra filter switching and PLL locking tim e
requirements.
When using a non-QSK
'
switching to
frequency, allowing
QSK operation
Once CW contact has been established with
another station, power can be reduced by rotating
the D RIVE control counterclockwise.
FM
The gain of the microphone amplifier during FM
transmission is preset internally for 5 kHz devia­
tion, so no adjustment by the operator is necessary .
The MIC gain control on the front panel is
disabled . RF p ower output can be adjusted by
the D RIVE control, so that the meter just deflects
slightly when the METER selector is in the (out)
ALC position, for full power operation. To reduce
power once contact is made, turn the D RIVE
control counterclockwise.
When the FT- 7 5 7GX i s u s e d in m obile opera­
tion, or with the FP- 7 5 7HD power supply,
full p ower FM (and AM or RTTY) transmis­
sions must be limited to one-half hour (30
minutes) or less.
When using the FT- 7 5 7GX with the FP-
7 5 7GX high duty-cycle power supply, full
power FM
transmissions must be limited to 30 seconds
or less. For longer transmissions, reduce
power to 50 watts.
However, when the FP-700, or similar light or
medium duty-cycle
transmitter power should be limited to about
50 watts at all tim es, to avoid overheating and
subsequent damage to the power supply .
Regardless of which type of power supply is
used, power output should be reduced from
the suggested levels if long transmissions
the
(more than 10 minu tes) are contemplated, or
the
if the am bient room temperature is very hot
or the power supply feels hot to the touch.
- 2 9 -
CAUTIO N
transmission is possible,
supply is used,
but
FM