CURSORY EVALUATION OF THE TA-1 TRANSMITTER ADAPTER

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03535A000600040017-2
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 2
• Document Creation Date: December 22, 2016
• Document Release Date: February 22, 2012
• Sequence Number: 17
• Publication Date: February 19, 1957
• Content Type: MEMO

Declassified in Part - Sanitized Copy Approved for Release 2012/02/22 : CIA-RDP78-03535A000600040017-2
Office Memorandum ? UNITED STATES GOVERNMENT
FROM
DATE: 19 February 1957
SUBJECT: Cursory Evaluation of the TA-1 Transmitter Adapter
1. A physical inspection of the Transmitter Adapter TA-i
revealed the following items:
a. The transmitter loading block is not held securely.
b. The telex earset phone tips short to the chassis when
they are inserted in the phone tip receptacle.
c. One edge of the chassis frame is not held down.
d. The circuit diagram is in error in regard to the taps
on the encapsulated coil where (0) position is shown
open. And the L4 coil is shown across the tank coil
in the LO position.
2. An electrical test of the Transmitter Adapter TA-1 coupled
to an ac receiver (RCA Model 6, RF-9) provided the following infor-
mation:
a. During normal operation of the TA-1 the bfo is on at all
times. This condition interferes with the reception of modulated
transmissions.
b. The transmit receive switch does not cut out or reduce
receiver volume when in the transmit position as it apparently
should do from the schematic.
c. Hand capacity greatly affects tuning of the transmitter
when adjusting for normal power output.
d. The calibration is not correct. Example: to tune to
e. The receiver input is by-passed (loaded down) with two
.005 ufd capacitors in series (bfo circuit) this condition may affect
the receiver sensitivity.
f. The power output of the transmitter TA-i was measured
with resistive loads in series with the .01 ufd blocking capacitor
to ground. The following results in tabulated form indicate power
output of the TA-1:
^?
STAT
Declassified in Part - Sanitized Copy Approved for Release 2012/02/22 : CIA-RDP78-03535A000600040017-2
 Declassified in Part - Sanitized Copy Approved for Release 2012/02/22 : CIA-RDP78-03535A000600040017-2
Fre
72.5 ohms
152 ohms
313 ohms
1558 ohms 1
1215 ohms
me
Po (watts)
;Po watts
Po watts
Po watts a
Po (watts)
3.5
3.14
3.26
3.3
3.8
3.67
3.5
3.39
3.56
3.94
3.5
2.26
3.26
3.65
3.94
2.56
3.42
2.71
2.3
.34
2
yt,~
o. 8 77
0. 8 3 , 974
~f~ ,-ate
o. 464 : o. 891,7j,-
``
{<
1. d9 /,
1.74
2.19 i
2.1
2.18
2.34
1.04
1.26
1.36
1.34
1.40
ac input voltage = 12OV/ac
* With the 1215 ohm load, the TA-1 did not load properly at this fre-
quency. (Band end)
g. Maximum power output on the high or low bands does not
coincide with the power outputs mentioned in the Transmitter TA-1 Equipment
Handbook.
3. Recommendations:
a. The schematic should be corrected to correspond to the final
circuit configuration.
b. The calibration should be corrected to provide the operator
with a nominal indication of correct operating frequency.
c. The chassis holes providing entry for the phone tips into
the phone tip receptacle should be insulated or enlarged to insure that
the tips do not short to the chassis.
d. The other mechanical defects listed under 1. a. & c. are
not considered serious but should be corrected if time permits.
e. No recommendation can be given concerning hand capacity
effects noticeable when tuning the transmitter because of the small size
of the packaged unit, proximity of antenna loading block to the hand
while tuning and of the fact that some hand capacity effects are normally
present in miniaturized transmitters.
f. An effective ON-OFF switch must be provided for the bfo.
STAT
STAT
Orig. - Design V 1 - A&A 1 - Dev/s
Declassified in Part - Sanitized Copy Approved for Release 2012/02/22 : CIA-RDP78-03535A000600040017-2