DDF550 Wideband Direction Finder by Rohde & Schwarz

Companies & Organizations:


Rohde & Schwarz GmbH & Co KG
Muehldorfstrasse 15
81671 Muenchen

The fast R&S®DDF550 wideband direction finder offers outstanding realtime bandwidth and DF scan speed as well as high DF accuracy, sensitivity and immunity to reflections. The unit has compact dimensions and is optionally available as a DC-powered model, which makes it ideal for mobile applications.


Key Facts


High DF accuracy, sensitivity and immunity to reflections

High DF scan speed due to outstanding 80 MHz realtime bandwidth (VHF/UHF/SHF)

Easy integration into mobile platforms due to compact size and optional DC power supply

DF antennas with integrated, extendible lightning protection causing no impairment of DF accuracy

Direction finding of signals in the frequency range up to 6 GHz


Features & Benefits


Direction finding of short-duration signals with high probability of intercept

- High DF scan speed due to outstanding 80 MHz realtime bandwidth

- Direction finding of short-duration and frequency agile signals with high probability of intercept

- Enhanced measurement speed (option)


Reliable DF results even in challenging environments

- Higher immunity to reflections due to DF antennas with a very large number of antenna elements (VHF/UHF/SHF)

- Stable bearings in VHF/UHF/SHF range even with a 50 % share of reflections


Innovative DF antennas

- Active/passive switchover with just a mouse click

- Exceptionally high DF sensitivity

- Integrated, extendible lightning protection

- Easy replacement of DF antennas


Precise direction finding of weak signals

- High DF sensitivity due to large number of antenna elements

- Adjustable coherent signal integration in wideband DF and DF scan mode for enhanced DF sensitivity


Accurate and reliable location of short-duration signals

- GPS based synchronization of multiple R&S®DDF550 (time-synchronized DF scan mode)

- Optional preclassifier detects LPI signals and summarizes individual results into a condensed result


Special and exceptionally powerful receive path for signal measurement

- Special and exceptionally powerful receive path

- Improved analog architecture of the receive path

- Especially powerful analog/digital converters

- Considerable advantages in the case of weak signals and dense signal scenarios


Powerful hardware developed by Rohde & Schwarz

- In-house development and manufacture of all DF system components, including the DF antenna

- Signal processing at maximum speed based on powerful FPGAs

- Use of powerful Rohde & Schwarz ASICs

- High immunity to strong signals thanks to sophisticated preselection


Effective measurements in line with ITU recommendations

The R&S®DDF550 fulfills all ITU recommendations for direction finders and receivers:

- Option for comprehensive, ITU-compliant measurement methods including, for example:

Frequency and frequency offset, field strength, modulation, spectrum occupancy and bandwidth


Direction finding up to 6 GHz

- Fast, effective radiolocation of interferers


Hardware-accelerated multichannel signal processing

- Multichannel signal detection and analysis in a networked system

- Parallel multichannel output of more than 100 channels

- Multichannel digital downconversion (DDC) signal extraction from the R&S®DDF550 realtime bandwidth with R&S®DDF550DDCE and R&S®CA120FFP

- Automatic detection of fixed frequency and burst signals with R&S®DDF550-HRP and R&S®CA120DSC

- Automatic detection of frequency agile short-time signals with R&S®DDF550-ST




Frequency range

                                               base unit                                                      20 MHz to 6 GHz

                                               with R&S®DDF550-HF, receive option        8 kHz to 6 GHz

                                               with R&S®DDF550-HF2, DF option            300 kHz to 6 GHz

DF mode

DF method                             VHF/UHF/SHF                                             correlative interferometer

                                               HF                                                                Watson-Watt

Realtime bandwidth                VHF/UHF/SHF                                            80 MHz

                                               HF                                                                20 MHz

Instrument DF accuracy                                                                              ≤ 0.2° RMS (typ.)

System DF                             depends on DF antenna (i.e. R&S®ADD011SR (.1x), R&S®ADD050SR,

accuracy1)                             R&S®ADD153SR and R&S®ADD078SR), in reflection-free environment,

                                               with lightning protection, in-line-with-report-ITU-R SM-2125

                                               300 kHz to 1300 MHz                                  0.5° RMS (typ.)

                                               1.3 GHz to 6 GHz                                        1° RMS (typ.)

DF sensitivity                          depends on DF antenna, for 2º RMS DF fluctuation, 2 s integration time

                                               and 250 Hz (HF)/ 600 Hz (VHF/UHF/SHF) DF bandwidth (i.e. R&S®ADD011SR (.1x),

                                                R&S®ADD050SR, R&S®ADD153SR and R&S®ADD078SR), in line with report ITU-R SM 2125

                                               300 kHz to 30 MHz                                      0.7 μV/m (typ.)

                                               20 MHz to 6 GHz                                         3 μV/m to 20 μV/m (typ.)

Minimum-signal-duration                                                                            1 ms

                                               with R&S®DDF550-EMS2) option               0.5 ms

Minimum-burst-duration   for multiple burst emissions                               20 μs


DF scan speed                      

HF (1.25 kHz channel resolution, 100 % channel

occupancy Watson-Watt method, wideband fixed

frequency mode, selectivity normal)

                                               base unit                                                      > 5 GHz/s,

                                                                                                                    in line with report ITU-R SM.2125

VHF/UHF (25 kHz channel resolution, 100 % channel

occupancy correlative interferometer method, wideband

fixed frequency mode) 

                                                base unit                                                      > 40 GHz/s,

                                                                                                                    in line with report ITU-R SM.2125


1) Measurement in reflection-free environment. The RMS error is calculated from the bearings of evenly distributed samples versus azimuth and frequency.


2) The R&S®DDF550-EMS option is export restricted.

Defense Products & Services: DDF550 Wideband Direction Finder by Rohde & Schwarz
Companies & Organizations: 
Defense Products & Services Sectors: Direction finding systems, ground-based
Country: Germany
Description: DDF550 Wideband Direction Finder
Source of Information: Rohde & Schwarz GmbH & Co KG