Full bars. Still waiting.: sources & model

Press jump on an original game, open the room around it, and discover where a reply spends its time. Share the radio with a tablet, inspect tiny waiting intervals, and compare a teaching signal model with real laboratory evidence.

What supports the explanation?

What this model assumes

1. The room, equipment, screen game and its prediction/fill strategy are original teaching assets. They are not real product CAD or a reconstruction of a specific game.
2. No device, router, RF spectrum, network identifier or browser connection estimate is measured. This page does not scan a network or run a speed test.
3. The main workload is one access point’s prepared downlink queue. No new background arrivals or partially served frames are included. Other stations have distinct queues and contention behavior.
4. The complete 200-byte and 1500-byte radio frames include assumed overhead; they are not those same amounts of application payload plus free protocol headers.
5. Receiver thresholds, 8 dB screens, transmit/noise settings, realized backoff draws, injected frame failure and local/external delays are authored conditions. Mathematical precision does not calibrate them to a home.
6. The interference control means a simultaneous uncoordinated contribution at the receiver. It is not the same as the separate sensed-busy trace.
7. Only a narrowband two-path field sum is modeled in its lens. It is not coupled to the room’s simpler free-space-plus-screens calculation.
8. The NIST scan is a primary historical material experiment. Source reference bands, specimen dimensions, normalization and fit status are retained; its 2–3 GHz gap is not invented.
9. Independent radio-engineering review and learner trials remain pending. Numerical tests and primary-source reading do not replace that review.
10. A precise but bounded radio example: The timing lens uses legacy 5 GHz, 20 MHz, non-HT OFDM: 20 µs of preamble/header, whole 4 µs data symbols, 16 SERVICE bits and six tail bits. T = 20 + 4 ceil[(16 + 8L + 6)/(4R)] µs for complete PSDU length L bytes and selected data-field rate R Mb/s. No aggregation, RTS/CTS or multi-user scheduling is modeled.
11. A source-checked exchange: For 200 complete frame bytes at 24 Mb/s, the PPDU is 88 µs. A 34 µs DIFS and seven realized 9 µs backoff slots precede it. Data reception occurs at 185 µs; a 16 µs SIFS and a 14-byte ACK at the selected 6 Mb/s basic rate extend completion to 245 µs. Seven is a chosen draw, not the mean of 0–15.
12. The queue calculation has a declared workload: Each prepared 1500-byte background frame occupies 401 µs of exchange/service time at 54 Mb/s, or 2181 µs at 6 Mb/s. Twenty frames therefore add 8.020 or 43.620 ms of waiting. The quiet reply takes 30.430 ms with the selected 30 ms external term; those two workloads give 38.450 and 74.050 ms.
13. Press-to-display and model reply are not interchangeable: The displayed reply metric runs from request radio eligibility to response DATA reception. The authored relay forwards the request after its MAC exchange completes. Two selected 8 ms local handling terms give the separately labeled press-to-display result. These are not an observed ICMP RTT or actual game benchmarks.
14. Free-space propagation and a room assumption: For the stated far-field isotropic comparison, loss is 20 log₁₀(4πdf/c). At 5 m and 5 GHz it is about 60.41 dB. With 20 dBm transmit power and zero antenna gains the received value is −40.41 dBm. Each intersected model screen adds an authored 8 dB, not a published material coefficient.
15. Logarithmic power needs care: Convert noise and simultaneous interference from dBm to milliwatts before adding: P(mW) = 10^(dBm/10). Divide the desired power by their sum to obtain SINR. A recognized competing Wi-Fi transmission that makes a station defer is not automatically an additive interferer during its own data frame.
16. A teaching receiver is not a chipset specification: Optional automatic mode selection uses authored thresholds: 8, 18 and 26 dB allow 6, 24 and 54 Mb/s. Below 8 dB it reports no supported mode. Real receivers have error probabilities, frame-length effects, rate adaptation and hardware differences omitted here.
17. Field amplitude is not power: For normalized direct amplitude 1 and reflected amplitude a, H = 1 + a exp(iφ). Relative power is |H|² = 1 + a² + 2a cosφ. At a = 0.5, in-phase, quarter-turn and opposed cases give 2.25, 1.25 and 0.25. This is a point comparison, not creation or disappearance of total field energy.
18. The wavelength comparison has a condition: At 5 GHz the vacuum wavelength is 0.059958492 m. A half-wavelength change in path-length difference adds π to propagation phase. Moving a receiver half a wavelength does not necessarily change the path-length difference by that amount. Wideband links and additional paths require a richer channel model.
19. A published fit is not raw data: The D50H curve reconstructs NISTIR 6055 Table 4.13d coefficients for nominal 13 mm drywall, only from 3 to 8 GHz. At 5 GHz it is about +0.21 dB relative to the experimental free-space reference. A positive reference-normalized receiver value does not imply a passive panel generates energy. It is not substituted for the model-room screens.
20. Wi-Fi evolved beyond this one exchange: The 1999 IEEE working-group record described 5 GHz OFDM with multiple rates. Current Wi-Fi models also include coordinated multi-user scheduling and OFDMA. OFDM tones are not automatically separate users. Our legacy timing lens remains a selected operating example, rather than a claim about every current device.
21. A brief burst is not necessarily bufferbloat: The prepared queue here eventually empties. A persistent standing queue can add delay without increasing the useful delivery rate; this motivates queue-management methods such as CoDel. This lesson does not implement CoDel or claim every burst is pathological.

What has been checked

Analytical reference cases, conservation or transition invariants, finite drawing commands, bounded setup parsing, discovery and route integrity are checked automatically. These checks do not establish anatomical fidelity, learner outcomes or browser/device compatibility. Independent subject review, learner trials, comprehensive accessibility review and browser video encoding checks remain pending.

Each source supports the associated claim. Sources do not certify this implementation or its visuals.

About the cover illustration

Original generic room, laptop, controller, access point and tablet geometry. An authored teaching scene; not a branded product teardown, RF scan or measured household layout.