Site: Deutsche Telecom Labs (FTZ)
Postfach 100003. 6100 Darmstadt
Germany

Date Visited: June 23, 1992

Report Author: C. Mahle

ATTENDEES

NASA/NSF:

C. Bostian
M. DeHaemer
C. Mahle

HOSTS:

Dr. Otto Schmeller

(S) Dept. President

R. Roga (PR)

(O)

Lichtenthaeler (PR)

(O)

G. Schuett

(S14)

H. P. Beck

(S31)

Dr. D. Exner

(S12)

H. Wannenmacher

(S15)

Dr. F. Dintelman

(F133)

Dr. V. Hombach

(F131)

BACKGROUND

FTZ is the laboratory of the German Posts, Telephone and Telegraph (PTT) (Deutsche Telecom, DT). They currently employ 3,250 people and expect this to rise to 4,500 as a result of additions from the former East Germany. The main laboratory, including the satellite communications department (Dept. S) headed by Dr. Schmeller, and several other sites are located in Darmstadt. DT invests about 20 billion DM/year in capital and R&D. The budget for R&D only was not available.

Dr. Schmeller's department represents DT in the technical subcommittees for INTELSAT (BG/T) and Inmarsat (ACTOM). In addition his department operates two satellite programs: DFS-KOPERNIKUS (two satellites in orbit) and TV Sat (one satellite in orbit, one satellite which failed to deploy its solar cell array panel). Satellite operations are conducted from an earth station in Usingen (near Frankfurt) under Dr. Schmeller's direction (Section S14). A new TV broadcasting satellite, called Pre-Europesat, is planned with German participation.

RESEARCH & DEVELOPMENT ACTIVITIES

FTZ performs research in only two areas of interest to this panel: radio wave propagation and antennas (satellite and earth station). Propagation research for the satellite slant path has been performed since 1970 using OTS and ECS as Ku-band beacon sources. In the late 1970s radiometers were added. They have performed detailed studies of site diversity; for their climate, 15 km is considered optimum at Ku-band. Data have been collected at 30/20 GHz since the launch of the Olympus satellite in 1989. It has been found that ice depolarization is a significant effect. Work is under way to correlate attenuation for slant paths with large separations (of the order of 500 km). There is no work under way to support mobile (L-band) satellite systems.

The antenna group is small (a few people), covering both earth terminal and satellite antennas. There is ongoing work on shaped reflector antennas. They have excellent analysis capability which has been used to develop corrugated horn feeds and for the design of a dual offset shaped reflector (4 m dia. main reflector). The cross-pol degradation due to thermal paint on the DFS-KOPERNIKUS satellite reflector antenna was analyzed here. They have designed a dual feed for angle diversity radio relay link antennas. Special struts to reduce sidelobes in a Cassegrain antenna were also developed here.

SUMMARY

DT FTZ does not perform much research specifically related to communications satellites. What they do, mainly in antennas and propagation, is of high quality. They influence both policy and the direction of communications satellite technology research and development in industry. In satellite operation, DT FTZ provides a number of services: TV distribution, Audio and TV broadcasting, data distribution and Public Switched Telephony Network (PSTN) using VSAT terminals for undeveloped areas (mainly in the east). There appears to be no interest in satellite applications for mobile communications except for the use of Inmarsat. There is no work in TV compression or digital TV at FTZ. DT is a knowledgeable satellite operator. They have stimulated the use of satellites for:

  1. TDMA (however, the domestic system using DFS-KOPERNIKUS is not used for PSTN anymore)
  2. TV distribution at 30/20 GHz
  3. TV broadcasting at 12 GHz (DBS, TV-SAT).

Current plans do not include any further satellite construction for domestic German use, although they will use existing satellite resources to provide access for the PSTN to areas in the east where terrestrial infrastructure is lacking. They will participate in European programs such as pre-EUROPESAT.


Published: July 1993; WTEC Hyper-Librarian