EXAMINATION OF HUNGARIAN "ORION" MICROWAVE WATTMETER TYPE 1382/B

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81-01043R002700120015-9
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 6
• Document Creation Date: December 23, 2016
• Document Release Date: January 28, 2014
• Sequence Number: 15
• Publication Date: October 7, 1958
• Content Type: REPORT

Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
. \
ri f: Bt. .. .701V OF PA ...1E FOR SPECIAL CONTROLS, I). ,
N.
C -07-N-F-I-D-E-N-T-I-A-L This material contains information affecting'
? `'. ? INFORMATION REPORT National Defense of the United States within the
meaning of the Espionage Laws, Title 18, U.S.C.
PREPARED AND DISSEMINATED BY Secs. 793 and 794, the trcmsmission or revelation
of which in any manner to an unauthorized pot.
CENTRAL INTELLIGENCE AGENCY son is prohibited by law. 50X1-HUM
COUNTRY
Hungary
SUBJECT
Examination of Hungarian "Orion" Microwave Wattmeter
Type 1382/B:
DATE DISTRIBUTED
7 October 1958
NO. OF PAGES I NO. OF ENCLS.
3
SUPPLEMENT TO REPORT #
50X1-HUM
THIS JS UNEVALUATED INFORMATION
1. MCN 14688 is a self-balancing thermistor bridge useful primarily as a
laboratory instrumett for measuring low output of microwave power, but
also useable for measuring the attenuation of microwave coupling and
attenuating devices as well as for measurements on transmitters, anten-
nae, and feed lines.
a. The self-balancing bridge is of a known type described, for instance,
in Microwave Measurements by Ginzton, McGraw Hill 1957, pp. 175-76.
The gain of the amplifier, used to balance the bridge, is approxi-
mately 1000 which means that the resistance of the sensing ther-
mistor will be about one ohm greater than that of the other bridge
arms (170 ohms) when the circuit reaches equilibrium.
b. A second thermistor bridge is coupled to the output of the bridge
feedback amplifier; thus, a signal proportional to the ampli-
tude of oscillations required to balance the first bridge is
supplied to the input of the second (metering and temperature
compensation) bridge. With no r.f. applied, the metering bridge
is adjusted for zero output as indicated by the vacuum tube volt-
meter. This null is achieved by adjusting a tapped resistance
(coarse and fine balance) in the arm of the bridge opposite
the thermistor: If a,null cannot be achieved by this method,
the power supplied to the sensing bridge can be varied by means
of a resistor (R) in series with the output of the feedback
amplifier.
c. Once the bridge has been zeroed, it can be calibrated on a given
range by means of the buit-in calibration circuit. A known value
of current (adjusted to the correct value by means of the "Cal.
Cur. Adj." control) is caused to flow through the r.f. sensing
bridge. Calibration is independent of long-term changes in
supply voltage, tube parameters, and temperature changes because
the calibration current can be measured and adjusted to the cor-
rect value before each measurement. The oscillator level changes,
causing the metering bridge to become unbalanced by a known amount
(which should cause full-scale deflection of the vacuum tube volt-
meter on the given range). The voltmeter is adjusted to show full-
scale deflection by means of the "Gain" control in the vacuum tube
voltmeter circuit,: 'The 'meter is then ready to operate, since r.f.
power applied to the sensing bolometer should cause the .same unbal-
amein the metering Circuit .,the equivalent d.c. power (neglect-
ing substitution error).
50X1-HUM
I !DISTRIBUTION
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? C-0-N-F-I-D-E-N-T7Ink-L
NAVY AIR tD/OS/ EV Et
50X1-HUM
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
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50X1 -HUM
d. The power supply is of the conventional, regulated variety
with a feedback amplifier and a gas diode reference.
e. By selection of appropriste radio-frequency measuring heads,
the power meter may be used in wide ranges of frequencies
and power levels. Because no measuring head was obtained
with the instrument, it was necessary to improvise a measur-
ing head of about 5 percent accuracy using an x-band bolo-
meter mount tuned fOr minimum reflections at 9,000 m.c. when
the enclosed Sperry 550 thermistor was biased to 170 ohms
resistance. A second Sperry 550 thermistor was fixed outside
the bolometer mount to provide the temperature compensation.
2. Conclusions advanced by the examing authority include the following:
a. MCN 111.688 is suitable for labrrratory and production applications
that require radio-frequency power measurements of moderate
accuracty within the power range of the instrument, at frequen-
cies from 0 to 10,000 megacycles provided a well-designed measur-
ing head is used.
b. No significant improvement over similar instruments of USA manu-
facture was noted.
(1) The temperature-compensation feature is advanced.
3. MCN 111.688 -.7as cOmpared with the U.S. Hewlett Packard Model 430C and
the Polytechnic Research & Development Company Model 630A pawermeters.
Each of these instruments uses a self-balancing bridge for the pur-
pose of re-establishing bt4dge balance when r.f. power is applied)
and they all use a calibrated vacuum tube voltmeter connected to
some point in the bride circuit to measure a change in signal level
which can be interpreted as indicating r.f. power level. All three
meters have similar accuracy when used with the appropriate r.f.
measuring head. Here the similarity ceases.
a. Neither the Hewlett Packard nor the PRD powermeters use temper-
ature compensation. One U.S. model powermeter, which is in the
designing stage uses a temperature compensating thermistor, which
is enclosed in the case of the powermeter rather than in the r.f.
measuring head. The temperature compensating resistor in MCN
111.688 is enclosed within the r.f. measuring head where it will do
the most good.
b. In both the Hewlett Packard and PRD meters the input to the
vacuum tube voltmeter is connected across the same bridge to
which the r.f. sensing element is attached. Therefore, in order
to obtain, zero signal output when no r.f. power is applied, some
d.c. bias must be used. No d.c. bias is necessary in MCN 111.688
because the meter circuit is placed across a separate thermistor
bridge which can beIalanced by varying the signal level and the
opposite arms of the bridge.
c. Probably the major weakness of MCN 111.688 is its lack of flexi-
bility with respect to the type of bolometer elements which may
be used with it. Both U.S. instruments may be used with either
thermistors or barreters at a fairly wide aLection of bias resis-
tances. MCN 111.688 is restricted to thermistor operated at a
bias resistance of 170 ohms. With certain modifications, it is
believed the instrument could be made more flexible with res-
pect to type and tias current of bolometer.
d. The power range of all of the instruments is similar, with MCN
111.688 having a lower maximum power reading as well as a lower
minimum full-scale reading.
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C-0-N-F-I-D-E-N-T-I-A-L
Declassified in Part - Sanitized Copy Approved for Release
50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
?
50X1 -HUM
e. The gain of the feedback amplifier in MCN 14688 is somewhat
greater than in the U.S. power meters; but, it is doubtful
that this contributes appreciably to the over-all accuracy
of the instrument.
f. A tabular comparison of the three meters follows:
Characteristic
Type
Comparison of Microwave Pawermeters
Instruments
Temperature
Compensation
DC Zero
Amplifiei. Gain
Meter across
bridge input
Meter across
bridge output
Vacuum tube voltmeter
Bolometer type
Bolometer resistance
Polytechnic
Res.&Dev.
Model 630A
Self-balancing
bridge
Hewlett Packard
Model 430C
Self-balancing
bridge
Orion-EMB
Woe 1382/B
Self-balancing
bridge
No No Yes
Yes
Up to 300
Power range
*T = Thermistor
B = Barreter
Yes No
X
X
X X
T,B* T1B*
50:100,1501
200,250
0.1-100 mw
full scale
-3-
100,200
1,000
X
X
T*
170
0.1-10 mw 0.03-5mw
full scale full scale
C-0-N-F-I-D-E-N-T-I-A-L
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/01/28: CIA-RDP81-01043R002700120015-9