INFORMAL MONTHLY PROGRESS REPORT NO. 5 FOR THE PERIOD 16 MAY 1955 THROUGH 12 JUNE 1955, INCLUSIVE

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81B00878R000200120025-5
• Release Decision: RIFPUB
• Original Classification: S
• Document Page Count: 12
• Document Creation Date: December 20, 2016
• Document Release Date: October 23, 2000
• Sequence Number: 25
• Content Type: REPORT

Approved For Release 2TErRorprDP81B00878R000200120025-5
*Ner
*USAF Declass/Release Instructions On File*
Informal Monthly Progress Report No. 5
For The Period
16 May 1955 through 12 June 1955, Inclusive
Contract No. A-101
CMCC Document No. 163.2005
Copy _L of 7
This document contains information affecting the
National Defense of the United States within the
meaning of the Espionage Laws, Title18, U.S.C.,
Sections 793 and 794. Its transmission or the
revelation of its contents in any manner to an
unauthorized person is prohibited by law.
SECRET
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Approved For Release 200S3ECRUP81B00878R000200120025-5
1.0 Antennas.
Four antennas and feeds have been matched on each frequency and
made ready for flight testing.
The S and X-band feeds were gold plated and were sealed at the
dipoles to resist corrosion. The S-band feed was sealed with .0015
inch Mylar sheet and Epon adhesive and the X-band feed was sealed
with .002 inch mica sheet and Epon adhesive. The completed S and
X-band assemblies, together with crystal holders, weigh 10.0 ounces
and 6. 3 ounces, respectively.
Since both horizontally and vertically polarized X-band trans-
missions will be received during operation, the X-band antennas will
be installed with the dipole axes 45? from horizontal to obtain equal
sensitivity for either polarization. This will result in a 3 db loss in
absorbed power.
In. a typical S-band V-beam radar set one beam is horizontally
polarized and one beam polarized 450 from horizontal. The re-
ceiving antenna is horizontally polarized and the 3 db loss in absorbed
power from the 450 beam serves as an aid in identifying the main beam.
The open circuit detector voltage for an incident r-f field intensity
of 1 milliwatt per square meter has been computed from measured an-
tenna gains and VSWR values for the antenna and detector. The com-
puted detector voltages are 28 millivolts at S band and 6 millivolts at
X band (including the 45? antenna rotation).
The dishes are being fabricated by the Raymond De-Icer Company.
The wooden molds being used are warping to the extent that it is almost
a certainty that production quantities cannot be obtained from the present
molds. The company is not willing to work from wood tooling for the
remaining quantities. The estimate for metal tooling is approximately
$7000.00 for the S and X-band dishes. For this reason, engineering
drawings of the dishes will be submitted to several companies for bids.
The original bids were made for antennas of a more experimental na-
ture. Complete drawings and specifications can now be furnished.
Ten S-band feeds are being manufactured by the contractor. Ven-
dors are being contacted to bid on the remaining quantities of S and
X-band feeds.
2.0 Information Amplifier.
The design of the information amplifier was completed after re-
ceipt of a satisfactory pulse transformer from Mag-Electric Co., of
Hawthorne, California. Figure 1 is a schematic diagram of the com-
pleted amplifier.
1
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Two minor changes have been included in the final design:
a. A trigger amplifier was added preceeding the one-shot multi-
vibrator that discharges the pulse stretching circuit. This main-
tains uniform pulse stretching throughout the dynamic range of
the amplifier.
b. The output stage has been converted to a cathode-follower.
Because of increased gain in the final design, amplification in
the output stage is no longer required.
Four hand-wired models of the prototype amplifier have been
completed and tested. A production model using printed wiring
has been designed.
Figure 2 is a curve of amplifier-output current as a function
of input voltage. Figure 3 is a curve of output current as a func-
tion of input pulse width. Figure 4 is a schematic diagram of the
high voltage power supply. The unit is designed to operate in am-
bient temperatures as high as 160?F.
3 0 Information Recorder.
Design of the production model of the recorder is about 50% com-
plete.
One prototype recorder has been assembled and a second proto-
type recorder is being assembled.
There is approximately 4% flutter in the prototype recorder. The
flutter arises from two primary sources, the gear teeth and the cap-
stan. A tuned filter consisting of a small flywheel and a fluid-damped
spring has been used in a variety of configurations without appreclable
success. The space and weight requirements of the recorder have
made it difficult to eliminate end effects and distortion in the compliance
elements of the filter. Tests using the flywheel and replacing the spring
with foam rubber were encouraging. Both a belt and rubber puck-type
drive will be completed for testing in the immediate future.
Tests using the prototype recorder indicated a noise level at ::he
reproducing head output of about 3 microvolts rms. The noise level
of the transistor monitor amplifier referred to its input was prohibi-
tively high -- between 50-100 microvolts rms. For this reason a
vacuum tube monitor amplifier (figure 5) was constructed. The noise
level of this unit, referred to the input grid, is less than 1 microvolt
rms.
Figure 6 is a schematic diagram of the transistor bias-oscillator.
At a frequency of 20.5 kc the unit supplies 0.6 ma rms bias current
to each recording track and 8 ma rms erase current. The frequency
2 ?
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deviation is 2 1/3 cps over the temperature range from 27?C to 87?C.
The voltage across the erase head varies less than 2% over the same
temperature range.
Information was received during this progress period that five
oscillators would be required for the timing track of the recorder.
There is enough room in the production design of the recorder to in-
corporate five transistor type R-C phase shift oscillators. The pres-
ence of each oscillator will indicate a timing event. Since these events
may occur simultaneously it is necessary to be able to filter and iden-
tify separate frequencies in the playback process. An R-C phase-shift
oscillator using two 903 silicon-junction transistors is being designed
to operate between 1 kc and 3 kc to accommodate the above require-
ments.
4. 0 Test Set.
Figure 7 is a complete schematic diagram of the test set. The
prototype model of the test set is presently being built and will be com-
pleted by the end of June. However, the S-band attenuator required for
the prototype model will not be delivered until July 10.
5. 0 Dubbing Equipment.
The first set of Ampex dubbing equipment has been received.
The playback recorder was modified to operate at the same speed
as the System 1 recorder. This was accomplished by replacing the
Ampex motor and capstan with a custom-made motor and capstan de-
signed to drive the cape at 2 1/4 inches per second. For tests usi,ig
the prototype recorder, a second motor and capstan was purchased
to drive the tape at 1 7/8 inches per second.
The recording amplifiers have been modified to equalize the pulse
response of the system. The re-recording is made at a tape speed of
7 1/2 inches per second. The output of the copy tape is a differentiated
pulse. To obtain a flat response from the information amplifier input,
to and including the playback of the copy tape, an adjustment of the
equalization control is required. Instructions for this adjustment, along
with copies of the tape and a Probe to eliminate the undesired peak of
the differentiated poise, will be provided.
These modifications and adjustments, without attempting to r,,-;pro-
duce the original poise waveform, provide faithful reproduction of rela-
tive amplitudes over a 40-46 db dynamic range and for pulse repetition
rates of 300-3000 pps.
Reproduction of the original recorded pulse-waveform through
equalization in the dubbing process would necessitate further extensive
modification in standard Ampex equipment and is not practical.
3
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6.0 Flight Tests.
The trainer aircraft will not be delivered in time for a mid-June
flight test. The flight test, therefore, has been rescheduled for the
early part of July.
7.0 Man-Hours Expended.
A total of 6718 man-hours was expended during the interval re-
ported in this progress letter.
7r ,'RET
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C+J
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CMOC NO. 241.307
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SECRET
4 MFD
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2.ALL CAPACITORS ARE IN MtviF.
I .ALL RESISTORS ARE IN OHMS 8, 1/2 W
NOTES: UNLESS OTHERWISE SPECIFIED.
VI
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5 SECRET
Approved For Release 2001/09/03 : CIA-RDP81600878R000200120025-5
CMCC No, 241,308
SECRET
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Signal In Millivolts (p-p).
RANGE AND LINEARITY OF AMPLITUDE
OF INFORMATION AMPLIFIER
6
SECRET
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CMCC No, 2141.309
SECRET
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Input Pulse Width - Microseconds
Figure 3 -- VARIATION IN OUTPUT AMPLITUDE VS. INPUT PULSE WIDTH
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7
SECRET
Approved For Release 2001/09/03 : CIA-RDP81600878R000200120025-5
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IN NO. I OUT IN NO. 2 OUT
2. ALL CAPACITORS ARE RATED IN MEDS.
I. ALL RESISTORS ARE RATED 1/2W.
NOTES; UNLESS OTHERWISE SPECIFIED:
Figure 5
MONITOR AMPLIFIER
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