OPERATING PROCEDURE FOR RT -21 AUTOMATIC TRANSMITTER

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03424A000800010062-6
• Release Decision: RIFPUB
• Original Classification: C
• Document Page Count: 7
• Document Creation Date: December 22, 2016
• Document Release Date: February 8, 2012
• Sequence Number: 62
• Content Type: MISC

Declassified and Approved For Release 2012/02/08: CIA-RDP78-03424A000800010062-6
C NHDENT ,
O TII PRO UB 'OR RT-21
AU'TOW C UiA EaLI7
- Connection of DC Power Source
0f) 1a7 TO-!U
1t e.
Before connecting the power source, the VFO or crystal should
be removed. A source capable of supplying 12 VSC plus or minus 1.5 VDC
at 2.5 amp should then be connected in accordance with the polarity mark-
ings on the case termini i.s .
Tuning Procedure
A. A suitable load should be connected between the antenaaa
terminal (A) and the ground. termini. A suitable load
is defined in the modified specifications as one whose
impedance lies within the 4 rea shown in Figure 1.
B. The band switch should be set to the frequency range
which includes the desired operating frequency.
C. Parer is applied to the transmitter via a switch which is
actuated when either a crystal or VFO jack is inserted.
The frequency of the crystal or VFO should be compatible
with the frequency range selected on the band switch.
Men the crystal or VFO is inserted, the tuning cycle is
automatically carried out. Neither the position of the
hand key nor the state of the automatic keyer has any
effect during the tuning:, cycle. If the automatic hey
is not inserted, the servo power is automatically turned
off at the completion of the tuning cycle. This is
indicated by the turning off of the blue indicator ligt.
F ;
.;?b C
just ka, pill
Declassified and Approved For Release 2012/02/08: CIA-RDP78-03424A000800010062-6
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1 XA
200 400 600 800 1000 1209
-200
400
-600
-800
-1000
-1200
-1400
00
FIGURE S'1
RA
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Jr, hawever, the automAtic key Jack is inserted, the
servo power (andd, the blue light) turned of at the
completion of the tuniz cycle ouiy If the hand key is
locked in the "on" position. (he c,bility to transmit
is not affected by whet r or not the servo power has
been turned off. oal y the power Grain is afectea. )
xzr - Trex fitting
At the ccMletian of the tun me cycle the transmitter may
be keyed either by the hand key or by the automatic keyer.
Declassified and Approved For Release 2012/02/08: CIA-RDP78-03424A000800010062-6
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Fxterxa1 Controls
Band Switch
The 3-30 me frequency range has been divided into the Z'ollo-
ing band : 3--7 me; 7-15 me; and 15-30 me. The switch should be posi-
tioned to the range which includes the desired operating frequency.
Frequency Source
The transmitter front panel contains a crystal socket and a
VFO Jack. The VFO Should be a constant voltage generator which will
apply 6 volts peek-to-peak across an impedance whose magnitude, depending
on the frequency, ranges between 50 ohms and 1000 ohms. (A generator
such as Tektronix Type 190 Constant Amplitude Signal Generator may be
used.)
Keying
Keying may be accomplished either by a hand key or by an
automatic keyer. The hand key is looked off when it is pushed in
against the case. Mien pulled out to the first position, normal heyin8
may be performed. The key may be locked down ("on") by pulling it out
to its second position. Automatic keying may be accomplished by inserting
the auto-key plug, subject to the follow-ln g constraints. in the "on"
state, a resistance path to ound(no greater than 10 ohms) should be
presented to the Auto-Key terminals. In the'bff"state, bias conditions
within the transmitter result in minus 16 volts existing across the
Declassified and Approved For Release 2012/02/08: CIA-RDP78-03424A000800010062-6
 Declassified and Approved For Release 2012/02/08: CIA-RDP78-03424A000800010062-6
Auto-Key terminals. In order to maintain this internal bias, the
Puto-Key terminals should be loaded with a grounded resistance no less
t1l,rM 50 kilohms.
IV - Break In operation
A relay is included in the transmitter circuitry to allow
break-in operation. When transmitting via the hand key, the antenna
terminal (A) Is connected to the receiver terminal (R) when the key is
in the "up" position. In then key "down" position, the antenna is
connected to the transmitter RF output. insertion of the Auto-Key
Jack results in the connection of the antenna only to the transmitter,
since break-in operation is no longer desirable.
The meter on the front panel is an indication of the RF voltngo
being applied at the input of the matching network. At the completion of
the tuning cycle, the meter should be at appro: ately half scale deflection.
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SIDE VIEW OF RT-21 TRANSMITTER
FIGURE 12
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TOP VIEW OF RT-21 POWER SUPPLY
FIGURE 13
Declassified and Approved For Release 2012/02/08: CIA-RDP78-03424A000800010062-6