Top Access Panel Controls - Yaesu FT-990 Operating Manual

Co11trols & Connectors- Top Access
Panel Controls
Top Access Pcmel Controls
(1) RTIY TONE
This miniature slide switch selects the tone
relationships of the Al::SK generator for R'ITY
transmissions. In the
NOliN
position, the SPACE
tone is transmitted while the key is open
(MARK
on closure}. In the
REV
position, the
MARK
tone is transmitted while the key is
o~
(SPACE on closure). You would nor-
mally keep
this
switch in the
NOliN
position and
select tone polarity with your terminal unit, if
possible.
(2) TONE DEY
This trimmer potentiometer adjusts the devia-
tion of the
88.5-Hz
subaudible toJ1e transmit-
ted (automatically} when operating FM on the
29-MHz
band with repealer split activated
(with the
RPT
button on the front panel).
Note: This and the follotuing
two
controls luroe been
preset at the factory to produce the correct deviation with
slam/art/ microphone leuds. A deuialion meterslzould
be
connected for
proper
· r eadjustment,
tiS
it
i5 difficult to
det~rmine
tire
proper
oetling by
ear,
(3) FN DEY
This trimmer potentiometer adjusts the maxi-
mum deviation of transmitted
FM
audio. See
the caution note above.
( 4) f'N Ml C GAIN
For FM transmission, this control adjusts the
microphone gail\. More clockwise settings pro-
duce greater deviation, and may cause distor-
tion if set too high. 'Readjustment should not be
necessary unless you are using an unusual
microphone.
(5) ANTI-TRIP
This o:>ntrol sets the level of negative feedback
of receiver a1,1dio to the microphone, to prevent
receiver audio from keying the transmitter (via
the microphone) during VOX operation. Ad-
justment is described in the Operation chapter.
(6)
VOX GAIN
This control sets the gain of
the VOX
(voice-ac-
tuated transmit/receive switching} circuit,
w hich de termines the level of microphone
audio needed to activate the transmitter dur-
ing
voice operation while the
vox
button on the
front panel is depressed.
(7) VOX DELAY
This control sets the hang time of
the VOX
circuit, between the moment you stop speak·
ing (or open the CW key during semi break-in
operation} and the automatic switch from
transmit back to receive (during VOX opera-
tion}. Adjust for
smooth VOX or
&em!
break-in
operation
(so
the receiver is activated only
when you want to listen).
(8) PKT, CW PITCH lo RTTY
DIP Switches
Switches 2 and 3 near the rear of this switch
block select the offset of the diSplay and
IF
passband center from the carrier, to match
most common packet
h\CS
used for 300-bnud
hf packet operation. Determine whid\ AFSK
tones are used by your tnc, and then set the
switches to match as shown below.
Packet FSKTone Pairs
DIP Sw<IChes
TNC Tooe Pair
(Hz)
107Wl270 1600fl800
2025.'2~
211012310
2
Off
On
orr
On
3
Off Off
On
On
Switches
4
and
5
select your desired CW tone
pitch, as shown below. The transmitter
sidetone frequency, and receiver IF passband
and display offset from the carrier frequency
are all affected.
CW Pitch Switches
OfP SWitches
OW Pitch IHll
700 600 500
I
400 _
4 Off
On 011
I
On
s
Off
Of1
I
On
I
On
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