SignalShark – Tracks down hidden interference with its top grade dynamic range
Pfullingen – Narda Safety Test Solutions presents the SignalShark, the
ideal monitoring receiver. Powerful, portable and versatile, and eminently suitable for
upcoming requirements for both mobile and fixed applications, it perfectly combines minimal
noise with high intermodulation immunity. The engineers at Narda, the RF measurement
technology specialist, have designed their latest development specifically for rapid and
reliable detection and analysis, classification and localization of RF emissions between 8 kHz
and 8 GHz. One of the commonest tasks in telecommunications measurements is an
examination of signal levels versus frequency. Here, users benefit from the extraordinarily
high dynamic range of the SignalShark. High Dynamic Range (HDR) in this context means
the ability of the SignalShark to reliably capture low-level signals in the presence of higherlevel
signals without problems. HDR necessitates a difficult balancing act between high
sensitivity for low levels and maximum insensitivity to saturation due to high levels in the
direct vicinity.
In practice, measurement engineers are often faced with the tricky situation when they need
to make high sensitivity measurements at locations close to VHF antennas or base stations
in order to trace unknown interference that is present at much lower levels. Narda’s
development team had to invest a huge amount of time and effort to solve this herculean
task. The result is a system that is as complex as it is ingenious. The SignalShark’s so-called
preselector makes it possible for it to suppress frequency ranges that would interfere with the
measurement. The preamplifier and first mixer stage define the low intrinsic noise (displayed
average noise level or DANL). The excellent dynamic range of the SignalShark is the result
of the ideal combination of DANL with the “insensitivity parameters”, that is the second and
third order intermodulation intercept points (IP2 and IP3).
In its “Handbook of Spectrum Monitoring”, the International Telecommunication Union (ITU)
describes how the ideal receiver should look from their point of view: minimal noise and
insensitive to intermodulation – expressed by the three parameters DANL, IP2, and IP3
(between 20 MHz and 3 GHz). The values for the SignalShark for frequencies between 20
MHz and 3 GHz are as follows: DANL = -159 dB (mW/Hz), IP2 = +30/+40 dBm and IP3 =+12 dBm.
A direct comparison using a graph with two superimposed triangles makes it clear
that Narda’s specifications are practically identical to the theoretical ideal values determined
by the ITU. This is an impressive and independent, neutral confirmation of the HDR qualities
of the SignalShark, which are unique for this class of device anywhere in its field.
