Filter
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4.6
RF ATT
4.10
AGC (AUTOMATIC GAIN CONTROL)
If the transceiver is operated in a short-distance (within
several ihundred meters) and strong signals of nearby fre-
quencies are received. the wanted signals are blocked. Also.
if the wanted signals are very strong. the S meter is scaled
out.
In this instance, set the ATT switch to ON. The input
signals to the RF amplifier are attenuated by about 20
dB.
providing distortionless reception.
4.7
RIT
By uslng the RIT knob, the receive frequency of VFO can be
shifted by about
i3 kHz and the frequency of fixed channel
by about
i150 Hz without changing the transmit fre-
quency.
II
the frequency of the opposlte station is deviated.
your receive frequency can be set to the
statton by turning
the RIT switch to ON and using the RIT knob. The state of
RIT can be checked bh the
indicator in the window of the
d~al.
4.8
IF SHIFT
By using the IF SHIFT knob during reception, rhe pass band
frequency of the crystal filter can be shifted by about
il
7 kHz because of adoption of PLL (Phase Locked Loop)
circuit in the local oscillator circuit. This is one of the major
features of TS-820 and can be used in the following cases:
1.
Adjustment of Tonal Quality and Interference Rejection
during SSB Reception.
When the transceiver is used in USB mode, turn the IF
SHIFT knob in the
"+"
direction and the lower frequen-
cies are cut out. Turning the knob in the direction
cuts out the higher frequencies (these procedures are
reversed for LSB mode). Adjust the knob so that the
to-
inal qual~ty suits your listening preference. The IF SHIFT
knob is also effective in eliminating interference when
the receive
s~gnals are superposed on nearby signals.
2.
Adjustment of Tonal Quality during
CW Operation
For detailed descriptions. refer to Section 4.13 "CW
operation".
3.
FSK IRTTY) Operation at 850
Hz
Shift
For detailed descriptions. refer to Section 4.19 "RTTY
operation".
4.9'
NOISE BLANKER
The TS-620 has a sophzsticated built-in noise blanker
des~gned to reduce ingition type impulse noise. The noise
blanker
is particularly ~mportant for mobile operation. When
necessary, activate the noise blanker circuit by flipping the
NB switch up.
Scl tlre AGC swirch to the position appropriate for the
rece~ved s~gnal. Generally for SSB reception set,the AGC
swtch to SLOW, for CW reception set the AGC switch to
FAST, and for reception of a very weak signal the switch
lnay be set to OFF.
4.1 1
TRANSMITTER TUNING
Connect the TS-820 to a 50 ohm dummy load or a 50 ohm
antclxla with an SWR of less than 2
:
1
before making any
transmitter adjustments. The life of the final tubes isdirectly
related to the SWR of the antenna and to the length of
tu-
nlng periods.
Refer to Table 2 for the initial switch settings of the
TS-820
for transmitting. Tune the main tuning knob to the desired
ol~eratiiig frequency.
PLATE
IDLING CURRENT (See Fig. 7)
Turn
lllc lnaln tuning knob to the desired operating Ire-
quency wltii~n the amateur band selected. Flip the stand-by
switch to SEND and check that the plate current
(IP) is 60
ma.
If the plate current is not correct. adjust the rear panel
BIAS control for a correct 60 ma of idling current and return
the stand-by switch to REC.
CAUTION: If the plate current is very much higher than 60
ma do not leave the stand-by switch on for more than a few
seconds. Excessive plate current shortens the life of the fi-
nal tubes.
DRIVE TUNING (See Fig.
8)
Shift the METER switch to ALC and the MODE switch to
TUN and peak the ALC reading (maximum meter deflection)
with the
DRIVE control. The stand-by switch is in the SEND
posltion for adjustment.
NOTE: If there is
no
ALC reading indicated. increase the
CAR control until there is an ALC reading.
PLATE TUNING (See Fig.
8)
Turn the METER switch back to IP, leave the MODE switch
at TUN and flip the stand-by switch to SEND. Quickly adjust
the PLATE control to dip the plate current (a minimum meter
readlng). Return the stand-by switch to REC.
NOTE: The TUNE position permits tuning of the final tank
clrcuit at reduced power without danger to the tubes. With
the MODE switch in the TUN position, the screen voltage of
the finals is reduced to approximately 50% and the keying
circuit is shorted.