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Feeder, Cable, Jumper: Three Commonly Confused Concepts in RF Engineering
Sep , 22 2026
These three concepts do not sit on the same logical plane. Cable is a material‑level generic term — any coaxial cable that carries RF signals, whether semi‑rigid, semi‑flexible, or braided, is called a cable. Feeder and jumper are functional‑level classifications — both are specific application forms of cable, distinguished by the role they play in the system. In one sentence: a feeder is the high...
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Three 10dB Couplers Compared: Insertion Loss and PIM Test Results – Cavity vs Microstrip vs Stripline
Sep , 29 2026
In DAS indoor distribution systems and RF link designs, the 10dB directional coupler is one of the most frequently used passive components. The two specifications engineers care about most are insertion loss and passive intermodulation (PIM) — the former directly eats into the link budget, the latter determines whether the uplink noise floor can be kept down. There are three main manufacturing tec...
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DAS Link Budget Calculation: A Step-by-Step Guide from RRU to Antenna Port
Oct , 13 2026
Why Is the Link Budget Always Off? The most frustrating part of DAS design isn't drawing the system diagram. It's calculating the antenna port power, thinking it's sufficient, and then measuring it on site to find it's off by 5 or 6 dB. Coverage shrinks, users complain, and when you trace it back you find — component insertion loss was undercalculated, feeder loss was estimated wrong, connector lo...
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Multi-Operator DAS: Band Combination Traps That Create Fatal Intermodulation
Oct , 27 2026
The most dangerous scenario in a multi-operator DAS is rarely caused by choosing a component with a poor PIM specification. The real problem often lies in the band plan itself — the frequency relationship between two downlink bands mathematically places intermodulation products inside another operator's uplink receive band. No matter how good the components are, the products land where they land. ...
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VSWR vs Return Loss vs Isolation vs Directivity: How These Four RF Parameters Connect
Nov , 03 2026
A conversation that happens on site more often than it should "What's the isolation on this coupler?" "22dB." "And directivity?" "Not listed. It only says isolation." "So can we use this part or not?" The conversation stalls here. 22dB isolation doesn't sound bad. But without directivity, you don't know whether that 22dB comes from "the forward coupled port and the reverse isolation port are well ...
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