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DAS vs IBS: What's the Difference? | In-Building Coverage Explained
Jun , 09 2026
1. The real problem: indoor signal is broken Over 80% of mobile traffic happens indoors — yet most buildings kill signal in seconds. Concrete walls, steel frames, low-E glass, underground parking: all block RF. From 2G to 4G, outdoor macro towers could still punch through building walls. That changed with 5G. Higher spectrum (3.5GHz to mmWave) barely penetrates. Even with boosted power, 5G signals...
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Low PIM Components: The Real Engineering Math From link budget to selection traps
Jun , 16 2026
Anyone who has worked on distributed antenna systems will eventually have a head‑on fight with PIM. This post skips the fluff and only shows the engineering math. 1. Where PIM comes from — the formula Two frequencies f1, f2 pass through a non‑linear node (loose connector, oxidized plating, magnetic material) and generate intermodulation products: 3rd order: 2f1－f2 , 2f2－f1 5th order: 3f1－2f2 , 3f2...
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PIM Interference vs. External Interference: How to Quickly Tell Them Apart On‑Site?
Jul , 07 2026
Anyone who does base‑station maintenance or network optimisation eventually runs into this: uplink noise floor spikes, users complain about dropped calls and low throughput, yet VSWR tests pass and there are no equipment alarms. Where is the problem? At this point, you have two possible culprits – PIM (passive intermodulation) interference generated inside your own system, or external RF interfere...
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5 Ways a Bad Passive Component Can Ruin Your DAS Link Budget
Jul , 14 2026
Designing a DAS link budget is an exercise in controlled optimism. You calculate cable loss per 100 meters, add up splitter and coupler insertion loss, account for connector transitions, and leave a few dB of margin for things you can't control. Then you order the components, install the system, and turn it on. And the numbers don't match. Not by a little. By 6, 8, sometimes 10 dB. Coverage holes ...
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4G Internal Antenna vs External Antenna: How to Choose the Right LTE Antenna
Jul , 21 2026
During the design of 4G LTE communication equipment, antenna selection is often one of the most critical decisions affecting wireless performance. For equipment manufacturers, system integrators, and wireless solution providers, a common question keeps coming up: Should I choose a 4G internal antenna or a 4G external antenna? Many engineers fall into a simple trap early in a project: “External ant...
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Combiner vs Duplexer: Not the Same Thing — A Complete Engineering Guide
Jul , 28 2026
Combiner and duplexer are not the same thing. A combiner is a device that merges two or more RF signals into a single output path, with all signals flowing in the same direction — primarily used for power combining on the transmit side. A duplexer is a three‑port device that isolates transmit and receive signals, allowing them to share a single antenna, with the two signal paths flowing in opposit...
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