Delivering leading solutions for today's field and maintenance challenges |
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With over 20 years leading the way in handheld testing Anritsu has a well earned reputation for superior measurements in not so superior conditions. learn more about the very latest handheld testing technology.
Click the article below to learn more...
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Understanding the Correlation Between Line Sweep and PIM Testing |
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Line sweep testing and
Passive Intermodulation (PIM)
measurements have become
essential to maintain wireless
network Quality of Service (QoS) and
achieve Key Performance Indicator
(KPI) benchmarks. Understanding
these two measurements and
how they work together to ensure
network performance are critical for
anyone working on high data rate
RF transmission systems.
While both line sweeping and
PIM are very important and help
determine a cell site’s ability to
perform optimally, they are very
different tests. Line sweeping
measures the signal losses and reflections of the
transmission system. PIM testing measures the ability
to transmit high-powered signals through the system
without generating self-interference. Defects that
cause high reflections can be very low PIM, while
defects generating high PIM may cause very low
reflections. Both tests are required to fully characterize
the construction quality of the transmission system.
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Line Sweep, Then PIM
PIM requires both low system loss and good return loss (VSWR) in order to adequately test system
performance. If PIM tests are performed prior to
line sweeping, the operator may not
be aware of impedance mismatch
problems in the transmission line. High
insertion loss attenuates the PIM test
signals, preventing the correct test
power level from reaching the very
components that require this stringent
testing. Poor return loss reflects a
percentage of PIM test signals back
into the test set, causing some
signal cancellation that can provide
misleading results.
By performing the line sweep test
prior to PIM testing, operators can
be confident that the PIM test signals
actually reach the components at the
highest possible signal level, offering
the most accurate indicator of true PIM performance.
Constructing a system using modern low PIM practices
will minimize the need to re-open the transmission
system. If the lines are disassembled a second time to
repair or clean a connector, the line sweep data must
be repeated.
Line sweeping and PIM tests are just two of the
many measurements that must be made to maintain
today’s wireless networks. Understanding how they
work together will help achieve optimum network
performance.
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Questions and Answers
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Question: Does Anritsu offer PC-based software tools for storing measurements and preparing
standardized reports?
Answer: Line Sweep Tools™ (LST), the latest generation of Anritsu Handheld Software Tools, are free and can be
downloaded at www.anritsu.com. This PC-based, post-processing software efficiently manipulates line sweep and PIM
traces, reducing the time necessary working with traces and preparing reports. LST enables users to easily collect
traces from the instruments, verify that the traces are correct using markers and limit lines, and report results in
industry-accepted PDF and/or DAT file format.
Question: What tools can I use to detect intermittent signals that are causing interference?
Answer: The MS2720T Spectrum Master™ is one tool that is excellent for locating intermittent signals. A burst detect feature
allows emitters as low as 200 μs to be captured. Plus, the MS2720T has extremely low phase noise, wide RBW range down to
1 Hz, and wide dynamic range, making it easy to detect intermittent signals even in the presence of steady signals.
Question: Can I sweep antennas close to another RF source?
Answer: Yes, but you need to be very careful that the RF from another source is not going to exceed the 23 dBm max
on the RF port of your measuring instrument. Power in excess of 23 dBm can result in damage to your analyzer. |
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Test Tip |
| When spotting PIM generated from modulated carriers, it is important to recognize that intermodulation created
from modulated signals takes more bandwidth than the fundamentals. For example, if both fundamentals are
1 MHz wide, the third order product may have a 3 MHz bandwidth, the fifth order product may have a 5 MHz
bandwidth, etc. |
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Remote Control Capability for PIM Master™ |
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Continuing to meet the needs of customers, Anritsu has developed Windows-based remote control software for
its PIM Master MW82119A, the industry’s first high-power, battery-operated, portable PIM test analyzer. With
the software, field technicians on the ground can control an MW82119A configured on top of the tower, making
it easier and more efficient to conduct highly accurate PIM measurements, especially for difficult-to-access sites,
such as Remote Radio Head (RRH) installations.
The free-of-charge software is compatible with any laptop or tablet operating with Windows XP SP2
through Windows 7 64 bit. Connection to the PIM Master MW82119A can be made over Ethernet
or compact Wi-Fi travel router. The new software continues Anritsu’s commitment to providing
the marketplace with test solutions that address field market conditions. The software
will work with all six PIM Master models, which address key frequency ranges, including
the upper and lower 700 MHz bands, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and
1900/2100 MHz.
The PIM Master MW82119A remote control software is now available
to download from the Anritsu website. |
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Site Master Shines on Project Done in
the Darkness of Night |
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When Russell McCalment was given the assignment of updating 20 sites in Colorado, he knew there was a
pretty good chance he and his crew would run into some less than friendly inhabitants, most notably bears
and Black Widow spiders. What he wasn’t sure of was if he would be able to see them, even if they were
right next to him.
It was all part of the job for the three-person crew that disconnected power
and telecommunications links from cabinets at the 20 designated sites – all
in the pitch black associated with sitting on a mountain in the middle of
the night. That’s because they had to do all the work from 11:00 p.m. to
6:00 a.m. That added a bit of a challenge to the crew, one they were ready
to tackle even when it became dicey.
“We had to cut galvanized steel and use heavy items in the dark because
of our service window. One of our guys had his thumb sliced by a tower
plinth,” said Russell.
Blood wouldn’t stop the team. After disconnecting the cabinets, they had to
slide each one to the other side of the respective platform or slab, secure
two plinths, run grounding and re-route jumpers to the new cabinet, as
well as install new jumpers. Once that was completed, the jumpers were
covered with a small, elevated ice bridge. The final step was to use the
Anritsu Site Master™ to sweep the jumpers prior to powering up the cabinet
to ensure the coax on each connector was working.
As if handling the heavy equipment in pitch blackness in the wee hours
of the night wasn’t enough, Russell and crew did have their share of
encounters with those bears and spiders. |
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| “One crew member was bitten more than a dozen times by spiders and other insects. He rushed to the emergency room, waited there for more than two hours, and then came back to the site. He is one tough dude!” said Russell.
The Site Master was also tough, handling the terrain without any difficulty. Durability was only one advantage of the Site Master. The small size and light weight of the Site Master were necessities for Russell and his crew. They spent countless hours under platforms in remote areas of the Rocky Mountains with one eye on the task at hand and the other looking to see what animal was lurking. Having something that was compact and durable was critical.
Of course, it always comes back to performance, and the Site Master excelled.
“The Site Master performed flawlessly. It enabled us to sweep all of our new jumpers as well as the complete system to insure proper service of the site before we turned it back on,” said Russell. |
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