![]() ![]() For example, if an antenna feed line has a connector with metal chips floating around inside, it is highly likely that it will fail a PIM test while the line sweep passes. Some cable faults show up best with a PIM test. Line sweeps and PIM testing are both important. Essentially, PIM testing will not find high Insertion Loss and Return Loss will not find high PIM. It is possible to have a PIM test pass while Return Loss fails, or PIM fail while Return Loss passes. It is important to remember that they are two independent tests,Ĭonsisting of mostly unrelated parameters that are testing opposite performance conditions within a cellular system. The PIM test is a measure of system linearity while a Return Loss measurement is concerned with impedance changes. The latter figure is hardly considered poor. Revealed an approximate 18% drop in download speed when residual PIM level was increased from –125 dBm to –105 dBm. ![]() On-site experiments have shown significant decreases in download speeds linked to slight increases in PIM. As cell usage and throughput grows, the peak power produced by the new digital modulations increasesĭramatically, contributing heavily to PIM problems. High-speed digital data communications make PIM testing critical. Impedance-based line sweeps, rather, it complements line sweeping, which is now more important than ever. It is worth noting that PIM testing does not replace PIM is a serious issue for cellular operators wanting to maximize their network’s reliability, data rate, capacity, and return on investment. Original transmitter power levels to make sure that the test reveals any PIM issues. PIM is created by high transmitter power so on-site PIM testing needs to be done at or above the This interference can affect both the cell that creates it, as well as other nearby receivers. PIM can create interference that will reduce a cell’s receive sensitivity or even block calls. PIM is a particular issue when overlaying (diplexing) new carriers into old antenna runs. PIM issues may occur as existing equipment ages, when co-locating new carriers, or when installing new equipment. PIM is a growing issue for cellular network operators. ![]()
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