REFLECTOMETER DEVELOPED AT VEK WERK FUER FERNMELDEWESEN HF, BERLIN-OBERSCHOENEWEIDE

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00810A007300670001-0
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 4
• Document Creation Date: December 20, 2016
• Document Release Date: January 9, 2008
• Sequence Number: 1
• Publication Date: July 8, 1955
• Content Type: REPORT

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CF~T TRAL -INTELLIGENCE AC~3J'CY
t.
INFORMATION REPORT
East Germany
Reflectometer Developed at YEB ~'~erk
fuer Fernmeldewesen HF, Berlin-
Oberschoeneweide
DATE OF INFO.
PLACE ACQUIRED
DATE ACQUIRED
This material contains information affecting the
National Defense of the united States within the
meaning of the Espona~e Laws, Title 18, U.S.C.
Secs. 793 and 794, the transmission or revel?
anon of which in any manner to an unauthorized
REQUIREMENT
REFERENCES
NO. OF PAGES
DATE DISTR.
REPORT
This is UNEVALUATED
Information
THE SOURCE EVALUATIONS IN THIS REPORT ARE DEFINITIVE.
THE APPRAISAL OF CONTENT IS TENTATIVE.
(FOR KEY SEE REVERSE)
1. From late 1952 until early 1955 VLB gFr~ .~ua~~. ~e:r~:rae1:'.c~:7a:^pn EF;=.i3er11A?
Oberschoenoweide worked on the development of ~. reflectometer with an
antenna-protecting device. The instrument had not been completed as of
did-1[ay 1955? It was ready for use as a switchbosatd instrument in trans-
mitters in early 1955. but further testing will ha~-e to be carried out
hA~ern it nun be used as a measuring device.
1:s o m - ay ?
reflectoneters had been constructs or u ra-short-wave trsnsmitters, 25X1
and 20 had been built for television transmitters.
2. The reflectometer is a measuring device which operates on the directional
coupler principle (Richtkoppler Prinzip)o A small coupling loop passes
through a slit into the hollow space of a coaxial conductor in such a way
that the loop and the internal conductor are in the same plane. outside
of the external conductor, the .coupling loop is provided on each side
with wave impedances which amount to about 80 to 100 ohms each. Erich
end of the loop passes through a detector to an ammeter. The free terms --
nals of the ammeter are .grounded. The capacity and inductivity of the
coupling loop are dependent on how far the loop goes into the hollow
space. If capacity and inductivit~' of the coupling loop are the sane,
the following vectorial situation results: when a high-frequency current
flows through the coaxial conductor in only one direction, its inductive
`-
component likowiae has only bne direction. The capacitative component
the samo absolute value but is divided into two opposing directional catr
ponente. Therefore, in half of the loop~the capacitative and inductive
components cancel each other out, and in the other half they are added,
es a result, no current flo;~ through one ammeter while the other ammete~
shows a definite reading. f, however, a part a.f the high-frequency
current is re!'lected, as for example in the case cf mis-matching of the
circuit, a Current reversal .occurs and the iigdnetive component, too,
is divided into two directions. 'Y-he instrument through. which forlaerly
no current wss flowing then shows 8 reading which corresponds to the
amount of the reversal, and the reading of the .ammeter through which 25X1
current~?>Ras originally flq~ring depresses by a-eorrasporiding amouiht.
Q1i`P7iFT ~.
rNote: Washington distribution indicated by "X": Field distribution by "#'T:
SECRET
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 the sensitivity of the reading can be greatly varied by changing the depth
of the loop. Sinoe the .part of the instrument which shows the reading
contains no resonating circuits and since the inductivity of the coupling
loop is small in comparison to the terminal resistanoes (abschliessende
Widorstaende), the frequency range din which the instrument operates is
very large. Good rea~ilte were obtained in the vioinity of 200 mos;; and it
~f~the-direct current is equal to the reversed current, which .occurs in
the case o~ total reflection, both instruments show the same" reading,
whioh is nne-half of the reading shown in the case of matching. Since the
readings of the instruments are dirgctly proportional to the current flow-
ing through them, the relationship of the two readings indiclates the
"waviness" (Welligkeit) of the conductoro I~iductivity and oapacfty.af"the
coupling look are closest to being equal when the depth of the loop amounts
to one-third the radius of the coaxial conductor. Since, however, both
values change more or less uniformly whey the depth of the loop is changed,
3?
and trarlsoonduotanoes have to be exaotly tha somas
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ie assumed that the ultimate f~.equency at whioh the instrument will operate
effeotively ie even highere
If a transmitter installation ie operated with high ourrent, a faulty
antenna oan ruin the transmitter. For this reaeon~ an antenna protection
devioe wa? built into the refleotometer whioh works in the following ways
if the reversed ourrent exoeede a oertain fixed amount. a highly o~eneitive
telegraph relay oloeee a 24-Volt diroot~-ourrent oirouit in ehioh a ebons-
ourront relay ie looatod. '1'~ie relay then oauees the anode voltage of tf,e
transmitter to bo out off. hie devio? has proved moat praotioal in ultra-
ohort=wave and t?lovieion transmitter? with a ourrent of hp to 10 kW.
The depth of th? loop oan b? regulated preoieely up to 1100 mm. by a
miorometor ?orew d~viae and oan bo a?t at any desired value. In uoing
the refl?otometer with the antenna protection dovioe~ it ie neoeeeary for
a oompen?ating r??iAtanoe to b? in?talled in th? ourrent reversal part
of the inotru~aont; the,oompeneating rooi?tanos ohould oorre0pond to the
reoiatanoe of tha winding of th? telegraph relay. ~~11 oonduotose belong-
ing to the art of the devioe whioh shows th+~ reading have to bo oarefully
ehielde8. ~e detootore must be a pair; that ie, their internal reeietano~~;
5?
or 70 Ohms
9 Telegraph relay (Type Siemens-Halske, 0.25 milli-xmp~
10 Strom-current rely (24 V) ~ ''
11 Tower supply .(220 V~
12 Blocking circuit
6. ~fl~~,arxr~?~:Y. No. 2 is the construction diagram of the reflectometer with
antenna protection deviceo
~n.nrlnaa3r: No. 1 is a circuit diagram of the reflectometer with antenna
protection devices
Coaxial conductor of up to 10 kW and 60
Internal conductor
External conductor
Loop (width 110 mm.)
Detectors (Type ED 704)
Wave resistances (0.1 Watt,, 80 Qha$)
Capacities (10,000 pF)
Coils (10~'wiridinge, 4 mm._diameter)
ammeter (up to 2 milli-&mpf~
Compensating resistance (2.5 ROha~
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T ~ ~. - - ~ -
rteflectometer circuit diagram
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i I--~-~--I 5
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Micrometer Reading
.._____
o '-~ 2 3 4 S ~ 7 8
~ Zero mark
Micrometer Scre~r
Coaxial Conductor
-4
Reflectometer construct=i_on di~ratri
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i