Cascaded Noise Figure Calculator: Model Your RF Receive Chain

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RF system design tool — GPIO Labs

Cascaded noise figure calculator

Model your full receive chain, stage by stage, and see exactly where system noise figure comes from. Cable runs count as stages — because in most real installs, the coax between your antenna and your first amplifier is doing more damage than any single component downstream.

How to use it: each card below is one stage in your chain, ordered from antenna (top) to receiver (bottom). Use the ↑ ↓ arrows on a card to move that stage earlier or later in the chain, and to remove it. Use the insert links between cards to add a new amplifier or cable stage at that exact position.

Stage order matters: whatever is stage 1 sees the signal first and dominates system noise figure. Use the insert links below to drop a new stage exactly where it belongs in the chain — for example, an LNA right before the receiver, ahead of its noisy front end.

System noise figure
— dB
Total gain
— dB
sum across all stages
Dominant stage

Set a target system noise figure. Given the chain above as everything after your preamp, this solves for the maximum noise figure that preamp can have — for a gain you specify — and still hit your target.