TELE-audiovision - The World’s Largest Digital TV Trade Magazine - page 42

TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine
— 03-04/2014
59. A span of 5MHz may be a small span
for CATV and satellite technicians but it
is a huge span for radio communication
specialists. Thanks to the very narrow
RBW filter of just 18 kHzW you can clearly
see all radio communications happening
within the selected span. In this case a
pilot is speaking to the tower.
60. Here you see the tower’s reply.
Because our test center is just 10 km away
from the airport we can clearly receive
such communications. The waterfall
display allows to register all communica-
tions within the span over a period of time.
Notice that the R&S EFL210 displays the
signal level accurately in µV/m, which is
the correct unit to measure EMI.
61. No transmission happening now on
121.10 MHz, the frequency used by the
OPO airport tower. Imagine the conse-
quences of a leakage, generating inter-
ference on this frequency. This could
severely disrupt the communication
between pilot and tower on a landing
62. This picture shows the full span of
aeronautics frequencies. This span is
universally used throughout the world.
Gladly no leakage could be detected in the
test center, otherwise we would have to
immediately correct the problem.
63. Here we see a communication happen-
ing on a different frequency. With the R&S
EFL210 I can now visually detect any radio
communication in this band at a glance,
instead of having to scan through known
frequencies or doing a frequency search.
64. A pre-programmed frequency range
is available to monitor the FM radio band.
This allows to analyze if interferences
occur between 88 Mhz and 108 MHz. Any
radio station can naturally be tuned in by
the R&S EFL210 and the audio is repro-
65. View of the FM band with a 20 MHz
span. Individual radio stations can clearly
be identified.
66. The full span of the GSM band. Two
frequencies are being used, but with a faint
signal. This is normal, since I am using a
smartphone with GPRS and EDGE frequen-
cies and usually GSM mode is turned off.
There is no other cellphone using GSM in
vicinity, either. Also, no leakage. This was
to be expected, because cable operators
avoid putting transponders at frequencies
this high.
67. Leakage measurement with the R&S
EFL-Z100 antenna. You can clearly see the
DVB-T transponder at 754 MHz and the
neighboring LTE transponder at 800 MHz.
Some transmission is happening at 742
68. The transmission at 742 MHz is highly
directional: pointing the R&S EFL-Z100
antenna to a different direction, nothing is
detected at this frequency.
69. The same happens to the mobile phone
transponder at 786 MHz. Further rotation
of the R&S EFL-Z100 and this transponder
disappears as well.
70. This is what leakage looks like. You
can clearly see the DVB-C transpond-
ers, despite the fact that I was using the
directional R&S EFL-Z100 antenna a few
meters away from the coaxial CATV cable.
This should never happen in real life, as
it means that radiation is coming out of
the coaxial cable, interfering with radio
71. The leakage is directional and with
the current orientation of the antenna, no
leakage is detected (spectrum in the upper
half of the screen). However, the waterfall
diagram clearly shows that leakage was
registered within the last seconds, when
the antenna was pointing to a different
direction. If you slowly move the antenna
from left to right, you will quickly find the
source of the leakage!
72. The antenna is pointing at the leakage
again, the CATV transponders are clearly
visible in the spectrum. Notice how the
waterfall diagram shows a faint signal
which is getting stronger as the antenna
points toward the leakage source. This is
an extremely useful functionality of the
EFL-210: you won’t just determine that
there is leakage occurring, you will indeed
find the source very quickly.
73. The waterfall diagram shows the UHF
section of the CATV cable in our test
center. You can clearly distinguish ana-
logue transponders from digital transpond-
ers: the thin lines belong to the analogue
transponders. Notice that they come in
pairs – one line is the video carrier, the
other the audio carrier.
74. Using an antenna no CATV transpond-
ers are found, which means that there is no
leakage in this frequency range. The signal
you see comes from different radio applica-
tions – I am using a radio scanner antenna.
75. Because the R&S EFL210 can deal with
frequencies up to 2.5GHz it is possible to
analyze the 2.4GHz Wi-Fi frequency range
as well. In these pictures you can see a
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