Ada Audits the Ad-Hoc Link Numbers
Ada re-derives this chapter’s own numbers step by step, at full precision
ADA · CALCULATION AUDIT
Ada Audits the Ad-Hoc Link Numbers
A factory ad-hoc link driven at 0 dBm over 50 m computes to -51.0 dBm, and the chapter’s practice link then reads 85% PDR, -73 dBm, and 30 ms latency — every check inside the GOOD band. It is tempting to promote that link to a production relay on the tier alone. This audit rebuilds the path-loss and threshold arithmetic and asks whether a matching GOOD tier settles the rollout, or whether backup-path and battery evidence must still clear first.
Companion to the chapter Ad-Hoc Deployment Framework — every number here comes from that chapter.
A routing graph is only as good as its radio evidence: the path-loss math, packet delivery tier, and latency threshold must all point to the same link decision.
1. The 50 m factory example rounds from the full path-loss calculation. With transmit power 0 dBm and environment factor n = 3:
At 100 m, the same model gives 0 - 30 x log10(100) = -60.0 dBm. Doubling from 50 m to 100 m costs 30 x log10(2) = 9.03 dB, which is the chapter's 9 dB warning.
2. The Excellent and Good distance thresholds come from solving the same equation.
| Threshold | Arithmetic | Distance |
| Excellent boundary, -70 dBm | log10(d) = 70 / 30 = 2.3333 | 10^2.3333 = 215.4 m |
| Good boundary, -80 dBm | log10(d) = 80 / 30 = 2.6667 | 10^2.6667 = 464.2 m |
3. The routing tier must agree across packet delivery, RSSI, and latency. The practice question's 85% PDR is inside the 70-90% GOOD band, -73 dBm is between -70 and -80 dBm, and 30 ms is inside the stated 20-50 ms latency band. All three checks support GOOD; a production controller should still keep backup-path and battery evidence before trusting that link as a relay.
Every number above is taken from the chapter’s own material and re-derived step by step.