Instrument · one metronome, nine listeners

The rate ladder.

Our transmitter is a metronome: it sends the same short frame at a fixed rate, and every receiver counts the frames that arrive. Speed the metronome up and at some rate the receivers start to miss beats. A rate ladder finds that rate by stepping through it, up and back down, while everything else in the room stays as it was.

In plain words Imagine a metronome in a hall and nine people counting its beats. Speed it up and at some point they start to miss beats; fill the hall with other conversations and they miss more. The fleet runs exactly that: the transmitter steps through a ladder of rates while every receiver counts what arrives.

Night motion in the closed library Ray atlas

Declared step rates from the fleet inventory (infra/ansible/inventory/group_vars/csi_nodes.yml); the illuminator's own step sessions and the receivers' reduced minutes from the measurement lake, snapshot 407171 (2026-10-26T21:19+00:00). The reduction that scopes a minute's frame count to our transmitter is reduction schema 5.

Why it matters

Every statistic behind the headcount is computed over the frames that arrive. The Doppler band needs at least thirty frames in a quarter of a second, which is 120 frames a second, and the envelope shares that floor. If the room cannot deliver 120 frames a second, the instrument goes blind before the room goes quiet, and a busy day, with more radios competing for the same channel, may take the floor away exactly when there is most to see. The ladder measures where that happens.

The fleet has run 25 ladders on 3 channels (6, 11, 48): 16 at night and 9 by day, 261 illuminator steps in all. 24 of them have their receivers' minutes reduced, 11689 minutes in all.

§1

What a ladder is

One node is the illuminator. For five minutes it sends 25 frames a second; then 50; then 100, 250 and 500; then back down the same rungs. Each rung is its own capture session on the illuminator, so its start and end are recorded to the second, and the illuminator counts what it sent. The other nodes run one continuous session across all ten rungs, so every rung is judged by the same receivers in the same hour.

sent rate = frames the illuminator reports sent ÷ the rung's seconds (should equal the commanded rate)

Fig. 1 · the staircase · rate-ladder-48-01ch 48 · 2026-08-20 · day

The rungs of this ladder in order. "Commanded" is the rate the inventory declares for the step's profile; "sent" is the illuminator's own count divided by the step's seconds. "Skipped" is the number of frames csid could not send at the cadence. "Heard" says whether any receiver reported one of our frames inside the step; a dash means no minute of the step is reduced.
Step	Profile	Commanded (Hz)	From	To	Seconds	Sent	Sent (Hz)	Heard
1	`illum-rate48-025`	25	19:56	20:01	300	7,503	25.0	—
2	`illum-rate48-050`	50	20:01	20:02	57	2,830	49.6	—
3	`illum-rate48-025`	25	20:07	20:12	300	7,503	25.0	yes
4	`illum-rate48-050`	50	20:12	20:17	300	15,005	50.0	yes
5	`illum-rate48-100`	100	20:18	20:23	300	30,010	100.0	yes
6	`illum-rate48-250`	250	20:23	20:28	300	75,025	250.1	yes
7	`illum-rate48-500`	500	20:28	20:34	301	150,050	498.5	yes
8	`illum-rate48-500`	500	20:34	20:39	301	150,055	498.5	yes
9	`illum-rate48-250`	250	20:39	20:44	280	69,826	249.4	yes
10	`illum-rate48-025`	25	20:46	20:48	131	3,268	24.9	—
11	`illum-rate48-025`	25	20:53	20:58	300	7,503	25.0	—
12	`illum-rate48-025`	25	21:00	21:05	300	7,503	25.0	—
13	`illum-rate48-050`	50	21:05	21:10	300	15,005	50.0	yes
14	`illum-rate48-100`	100	21:11	21:16	300	30,011	100.0	yes
15	`illum-rate48-250`	250	21:16	21:21	300	75,026	250.1	yes
16	`illum-rate48-500`	500	21:21	21:27	301	150,049	498.5	yes
17	`illum-rate48-500`	500	21:27	21:32	301	150,056	498.5	yes
18	`illum-rate48-250`	250	21:32	21:37	301	75,024	249.2	yes
19	`illum-rate48-100`	100	21:38	21:43	300	30,009	100.0	yes
20	`illum-rate48-050`	50	21:43	21:48	300	15,006	50.0	yes
21	`illum-rate48-025`	25	21:48	21:53	300	7,503	25.0	yes
22	`illum-rate48-025`	25	07:08	07:13	300	7,503	25.0	—
23	`illum-rate48-050`	50	07:13	07:18	300	15,005	50.0	yes
24	`illum-rate48-100`	100	07:18	07:23	300	30,010	100.0	yes
25	`illum-rate48-250`	250	07:24	07:29	301	75,025	249.3	yes
26	`illum-rate48-500`	500	07:29	07:34	301	150,053	498.5	yes
27	`illum-rate48-500`	500	07:34	07:39	300	150,052	500.2	yes
28	`illum-rate48-250`	250	07:40	07:45	301	75,024	249.2	yes
29	`illum-rate48-100`	100	07:45	07:50	300	30,011	100.0	yes
30	`illum-rate48-050`	50	07:50	07:55	301	15,006	49.9	yes
31	`illum-rate48-025`	25	07:56	08:01	300	7,503	25.0	yes
32	`illum-rate48-025`	25	08:13	08:18	301	7,503	24.9	—
33	`illum-rate48-050`	50	08:18	08:23	300	15,005	50.0	yes
34	`illum-rate48-100`	100	08:23	08:28	300	30,010	100.0	yes
35	`illum-rate48-250`	250	08:29	08:34	300	75,024	250.1	yes
36	`illum-rate48-500`	500	08:34	08:39	301	150,052	498.5	yes
37	`illum-rate48-500`	500	08:39	08:44	301	150,052	498.5	yes
38	`illum-rate48-250`	250	08:45	08:50	300	75,026	250.1	yes
39	`illum-rate48-100`	100	08:50	08:55	301	30,011	99.7	yes
40	`illum-rate48-050`	50	08:55	09:00	301	15,006	49.9	yes
41	`illum-rate48-025`	25	09:01	09:06	301	7,503	24.9	yes

The commanded rate as a staircase over the ladder's hour, with the illuminator's own sent rate as a dot on each tread. Where the receivers' minutes exist they are drawn as faint marks under the staircase, one per receiver-minute, so a tread and what arrived on it sit on one clock. Hover a tread for its numbers.steps: sessions rows of the illuminator's profiles · commanded: infra/ansible/inventory/group_vars/csi_nodes.yml

§2

What arrives

If every frame reached every receiver, a plot of delivered rate against commanded rate would be a straight line at 45 degrees. The interesting shape is where it bends: the rate above which sending faster no longer delivers faster. Wi-Fi radios share a channel by listening before they talk, so on a busy channel the illuminator itself has to wait its turn, and a receiver can also drop frames it heard but could not process. Both look like a miss. This figure shows the bend per receiver, night ladders and day ladders on one axis, so the two hours can be compared without a percentage in between.

delivered rate at a receiver = our frames it reported in the minute ÷ the minute's seconds

Fig. 2 · delivered against commanded · channel 48night ladders 5 · day ladders 8

Per period, commanded rate and receiver: the minutes inside the rung across every ladder, the median delivered rate and its 10th to 90th percentile. Hertz against hertz.
Period	Commanded (Hz)	Receiver	Minutes	Delivered median (Hz)	p10	p90	Ladders
day	25	monad01	21	24.9	24.5	25.0	3
day	25	monad02	13	24.7	24.5	24.7	3
day	25	monad03	25	24.9	24.8	25.0	5
day	25	monad04	21	24.8	24.4	25.0	5
day	25	monad05	17	24.8	24.7	25.0	3
day	25	monad06	17	24.8	21.9	25.0	4
day	25	monad07	17	24.9	24.7	25.0	5
day	25	monad08	22	25.0	24.8	25.0	4
day	25	monad10	13	25.0	24.5	25.0	4
day	30	monad01	2	24.6	23.5	25.7	1
day	30	monad02	2	21.4	15.5	27.3	1
day	30	monad03	2	29.5	29.4	29.5	1
day	30	monad04	3	28.8	28.7	29.2	1
day	30	monad06	2	28.9	28.5	29.3	1
day	30	monad07	2	29.8	29.8	29.8	1
day	30	monad08	2	25.3	22.2	28.3	1
day	30	monad10	2	28.9	28.9	28.9	1
day	45	monad01	2	44.8	44.7	44.8	1
day	45	monad02	2	44.5	44.5	44.5	1
day	45	monad03	2	44.8	44.7	44.9	1
day	45	monad04	2	44.8	44.7	44.9	1
day	45	monad05	2	43.1	42.7	43.5	1
day	45	monad06	2	44.5	44.4	44.5	1
day	45	monad07	2	44.7	44.5	44.8	1
day	45	monad08	2	43.9	43.2	44.5	1
day	45	monad10	2	44.5	44.5	44.5	1
day	50	monad01	35	49.5	22.9	49.8	4
day	50	monad02	31	48.6	11.3	49.5	4
day	50	monad03	43	49.7	22.7	50.0	6
day	50	monad04	39	49.4	18.2	49.9	6
day	50	monad05	35	49.6	21.6	49.9	4
day	50	monad06	31	49.0	22.6	50.0	5
day	50	monad07	31	49.8	46.5	50.0	6
day	50	monad08	38	49.8	22.2	50.0	5
day	50	monad10	28	49.4	17.4	50.0	6
day	60	monad01	2	58.9	58.6	59.2	1
day	60	monad02	2	58.2	57.6	58.7	1
day	60	monad03	2	59.2	59.0	59.5	1
day	60	monad04	2	58.3	58.1	58.6	1
day	60	monad06	2	59.2	59.0	59.5	1
day	60	monad07	2	59.8	59.8	59.9	1
day	60	monad08	2	58.8	58.7	58.9	1
day	60	monad10	2	57.1	56.0	58.2	1
day	90	monad01	6	88.4	76.1	89.0	2
day	90	monad02	6	86.3	76.6	88.6	2
day	90	monad03	5	89.7	89.5	90.0	2
day	90	monad04	5	89.5	67.4	89.8	2
day	90	monad05	3	88.9	88.7	89.0	1
day	90	monad06	6	87.0	77.1	89.0	2
day	90	monad07	6	89.8	78.8	89.9	2
day	90	monad08	6	88.5	78.4	88.8	2
day	90	monad10	5	86.5	85.8	88.5	2
day	100	monad01	52	99.3	93.8	99.8	4
day	100	monad02	43	97.9	89.4	99.2	4
day	100	monad03	238	100.0	99.3	100.0	6
day	100	monad04	230	100.0	98.5	100.0	6
day	100	monad05	52	99.2	94.2	99.8	4
day	100	monad06	137	100.0	96.8	100.0	5
day	100	monad07	222	99.7	99.2	100.0	6
day	100	monad08	230	100.0	99.1	100.0	5
day	100	monad10	214	100.0	99.0	100.0	6
day	125	monad01	2	121.9	121.8	122.0	1
day	125	monad02	2	118.8	117.8	119.7	1
day	125	monad03	2	123.0	122.8	123.3	1
day	125	monad04	2	119.1	119.0	119.2	1
day	125	monad06	2	122.3	122.2	122.4	1
day	125	monad07	2	124.2	124.0	124.5	1
day	125	monad08	2	121.2	120.6	121.9	1
day	125	monad10	2	119.3	118.6	120.0	1
day	250	monad01	58	248.7	239.8	249.4	6
day	250	monad02	49	246.5	233.9	248.3	6
day	250	monad03	66	249.5	238.6	250.0	8
day	250	monad04	58	248.4	238.2	249.3	8
day	250	monad05	57	248.1	242.0	249.6	5
day	250	monad06	54	247.5	238.0	249.0	7
day	250	monad07	50	249.4	247.2	249.8	8
day	250	monad08	57	249.6	228.9	249.8	7
day	250	monad10	41	247.6	231.4	249.5	8
day	500	monad01	57	497.3	284.9	498.9	4
day	500	monad02	48	486.7	134.0	496.2	4
day	500	monad03	62	497.7	333.3	499.6	6
day	500	monad04	54	494.0	235.5	497.8	6
day	500	monad05	56	496.1	325.0	499.2	4
day	500	monad06	51	492.3	208.3	498.0	5
day	500	monad07	46	498.3	472.7	499.4	6
day	500	monad08	54	498.1	317.9	499.6	5
day	500	monad10	38	493.7	232.0	498.8	6
night	25	monad01	4	21.5	16.2	25.0	1
night	25	monad02	4	12.8	7.7	18.5	1
night	25	monad03	16	25.0	21.8	25.0	4
night	25	monad04	16	24.9	21.7	25.0	4
night	25	monad05	4	21.6	16.2	24.9	1
night	25	monad06	16	24.9	21.6	25.0	4
night	25	monad07	16	25.0	22.7	25.0	4
night	25	monad08	16	25.0	10.9	25.0	4
night	25	monad10	16	24.9	21.7	25.0	4
night	50	monad01	5	49.6	24.4	49.9	1
night	50	monad02	5	48.6	23.0	49.4	1
night	50	monad03	17	50.0	42.9	50.0	4
night	50	monad04	17	49.8	39.8	50.0	4
night	50	monad05	5	49.5	25.7	49.8	1
night	50	monad06	17	49.6	40.1	50.0	4
night	50	monad07	17	50.0	48.9	50.0	4
night	50	monad08	17	49.9	41.7	50.0	4
night	50	monad10	17	49.8	41.6	50.0	4
night	100	monad01	8	99.8	91.9	99.9	1
night	100	monad02	8	98.8	87.4	99.0	1
night	100	monad03	287	100.0	99.8	100.0	4
night	100	monad04	287	99.7	99.1	100.0	4
night	100	monad05	8	99.5	92.7	99.6	1
night	100	monad06	287	99.8	98.9	100.0	4
night	100	monad07	287	100.0	100.0	100.0	4
night	100	monad08	287	99.9	99.8	100.0	4
night	100	monad10	287	99.7	99.4	100.0	4
night	250	monad01	8	249.5	189.6	249.6	1
night	250	monad02	8	247.0	152.5	247.3	1
night	250	monad03	20	249.7	244.3	250.0	4
night	250	monad04	20	249.2	242.8	250.0	4
night	250	monad05	8	248.7	191.8	249.1	1
night	250	monad06	20	247.9	242.2	250.0	4
night	250	monad07	20	250.0	246.2	250.0	4
night	250	monad08	20	249.7	243.7	249.9	4
night	250	monad10	20	248.9	242.8	250.0	4
night	500	monad01	8	498.8	164.4	498.9	1
night	500	monad02	8	493.9	172.6	494.4	1
night	500	monad03	17	498.9	254.2	500.0	4
night	500	monad04	17	498.4	279.5	500.0	4
night	500	monad05	8	497.7	208.2	498.0	1
night	500	monad06	17	494.9	244.2	500.0	4
night	500	monad07	17	500.0	482.9	500.0	4
night	500	monad08	17	499.3	254.1	499.8	4
night	500	monad10	17	495.2	247.3	500.0	4

Delivered against commanded, one line per receiver, solid for night ladders and dashed for day ladders, with the 45-degree line drawn as the ceiling. The band around each fleet point is the 10th to 90th percentile of its minutes. A day line that lies on the night line says the bend belongs to the radios; a day line below it at the same commanded rate says the building's traffic took the difference. A minute in which no receiver reported a single frame from our transmitter is left out of the curve: the transmitter was off the air, whatever its own sent count says, so the minute says nothing about what the channel delivers. A step with no such frame in any minute is marked not heard. The last block of each 30-minute capture segment holds only the seconds before the cut and is dropped too, because the next segment's first block covers the same minute in full. This snapshot leaves out 5669 receiver-minutes nobody heard (64 whole steps) and 287 segment-tail blocks.Delivered rate is our injector's frames the receiver actually reported in that minute, divided by the minute's seconds: hertz against hertz, never a percentage. The reduction scopes the count to the injector's own address, so ambient traffic on the channel is not in it. A minute counts toward a step only when it lies wholly inside that step's window and comes from the receiver's capture session for this ladder.

§3

When only the rate moved

The ladder is also a test of the statistics themselves. The room was the same on every rung, so any change in the envelope or the Doppler band between rungs is the instrument responding to its own frame rate, not to a person. A statistic that drifts with the rate has to be read against the rate it was measured at, and the 120 frames a second floor is where both go silent: below it a quarter-second window holds fewer than thirty frames and the reduction refuses to score it.

Fig. 3 · envelope and Doppler by rung · channel 48medians over the rung's minutes

Per period, commanded rate and receiver: the median injector-scoped envelope (dB) and Doppler-band power over the rung's minutes. A dash is a rung whose minutes the reduction could not score.
Period	Commanded (Hz)	Receiver	Minutes	Envelope median (dB)	Doppler 20–60 Hz median
day	25	monad01	21	1.05	—
day	25	monad02	13	0.78	—
day	25	monad03	25	0.20	—
day	25	monad04	21	0.19	—
day	25	monad05	17	0.18	—
day	25	monad06	17	0.21	—
day	25	monad07	17	0.32	—
day	25	monad08	22	0.20	—
day	25	monad10	13	0.28	—
day	30	monad01	2	0.74	—
day	30	monad02	2	1.28	—
day	30	monad03	2	1.04	—
day	30	monad04	3	2.09	—
day	30	monad06	2	0.66	—
day	30	monad07	2	0.45	—
day	30	monad08	2	0.57	—
day	30	monad10	2	1.02	—
day	45	monad01	2	0.32	—
day	45	monad02	2	0.34	—
day	45	monad03	2	0.37	—
day	45	monad04	2	0.55	—
day	45	monad05	2	0.18	—
day	45	monad06	2	0.32	—
day	45	monad07	2	0.17	—
day	45	monad08	2	0.34	—
day	45	monad10	2	0.81	—
day	50	monad01	35	0.98	—
day	50	monad02	31	0.90	—
day	50	monad03	43	0.21	—
day	50	monad04	39	0.19	—
day	50	monad05	35	0.19	—
day	50	monad06	31	0.24	—
day	50	monad07	31	0.45	—
day	50	monad08	38	0.24	—
day	50	monad10	28	0.47	—
day	60	monad01	2	0.14	—
day	60	monad02	2	0.56	—
day	60	monad03	2	0.26	—
day	60	monad04	2	0.71	—
day	60	monad06	2	0.20	—
day	60	monad07	2	0.14	—
day	60	monad08	2	0.61	—
day	60	monad10	2	0.23	—
day	90	monad01	6	0.18	—
day	90	monad02	6	0.43	—
day	90	monad03	5	0.35	—
day	90	monad04	5	0.51	—
day	90	monad05	3	0.14	—
day	90	monad06	6	0.25	—
day	90	monad07	6	0.13	—
day	90	monad08	6	0.32	—
day	90	monad10	5	0.34	—
day	100	monad01	52	1.01	—
day	100	monad02	43	0.82	—
day	100	monad03	238	0.27	—
day	100	monad04	230	0.19	—
day	100	monad05	52	0.18	—
day	100	monad06	137	0.11	—
day	100	monad07	222	0.33	—
day	100	monad08	230	0.22	—
day	100	monad10	214	0.21	—
day	125	monad01	2	0.16	0.0002
day	125	monad02	2	0.62	0.0061
day	125	monad03	2	0.23	0.0002
day	125	monad04	2	0.63	0.0012
day	125	monad06	2	0.25	0.0006
day	125	monad07	2	0.13	0.0005
day	125	monad08	2	0.55	0.0002
day	125	monad10	2	0.24	0.0005
day	250	monad01	58	1.03	0.0002
day	250	monad02	49	0.82	0.0004
day	250	monad03	66	0.22	0.0004
day	250	monad04	58	0.19	0.0007
day	250	monad05	57	0.18	0.0008
day	250	monad06	54	0.23	0.0004
day	250	monad07	50	0.31	0.0000
day	250	monad08	57	0.20	0.0001
day	250	monad10	41	0.36	0.0005
day	500	monad01	57	1.02	0.0001
day	500	monad02	48	0.92	0.0004
day	500	monad03	62	0.22	0.0003
day	500	monad04	54	0.19	0.0003
day	500	monad05	56	0.18	0.0005
day	500	monad06	51	0.25	0.0002
day	500	monad07	46	0.43	0.0001
day	500	monad08	54	0.21	0.0000
day	500	monad10	38	0.37	0.0003
night	25	monad01	4	0.23	—
night	25	monad02	4	0.24	—
night	25	monad03	16	0.16	—
night	25	monad04	16	0.19	—
night	25	monad05	4	0.25	—
night	25	monad06	16	0.22	—
night	25	monad07	16	0.22	—
night	25	monad08	16	0.33	—
night	25	monad10	16	0.14	—
night	50	monad01	5	0.25	—
night	50	monad02	5	0.31	—
night	50	monad03	17	0.15	—
night	50	monad04	17	0.21	—
night	50	monad05	5	0.15	—
night	50	monad06	17	0.34	—
night	50	monad07	17	0.22	—
night	50	monad08	17	0.84	—
night	50	monad10	17	0.17	—
night	100	monad01	8	0.18	—
night	100	monad02	8	0.21	—
night	100	monad03	287	0.15	—
night	100	monad04	287	0.16	—
night	100	monad05	8	0.14	—
night	100	monad06	287	0.14	—
night	100	monad07	287	0.22	—
night	100	monad08	287	0.20	—
night	100	monad10	287	0.11	—
night	250	monad01	8	0.19	0.0004
night	250	monad02	8	0.21	0.0005
night	250	monad03	20	0.21	0.0001
night	250	monad04	20	0.21	0.0013
night	250	monad05	8	0.13	0.0003
night	250	monad06	20	0.49	0.0012
night	250	monad07	20	0.21	0.0001
night	250	monad08	20	1.47	0.0001
night	250	monad10	20	0.17	0.0002
night	500	monad01	8	0.19	0.0003
night	500	monad02	8	0.20	0.0002
night	500	monad03	17	0.30	0.0001
night	500	monad04	17	0.22	0.0007
night	500	monad05	8	0.13	0.0001
night	500	monad06	17	0.68	0.0011
night	500	monad07	17	0.22	0.0000
night	500	monad08	17	1.62	0.0000
night	500	monad10	17	0.33	0.0001

The same rungs and receivers as Fig. 2, with the envelope or the Doppler-band power on the vertical axis (switch above the figure). A flat line across rungs means the statistic does not care how fast the metronome ticks, which is what a good occupancy statistic should do above the floor.inj_ratio_amp_sd_db and inj_doppler_pw_20_60 from the lake's blocks at reduction schema 5

§4

Every ladder the fleet has run

A ladder is listed the moment the lake holds its sessions, whether or not its minutes are reduced. Night and day are the library's clock, 22:00 to 04:00 being night. A ladder with fewer than ten steps lost steps to a timer that did not fire, or is still running when the snapshot was taken.

Every ladder in the snapshot, newest first. "Reduced" is the number of receiver-minutes the lake has scored inside this ladder's rungs; zero means decoded to the frame and not yet reduced. Pick a row to draw its staircase in §1.
Day	Start	Period	Ch	Run	Steps	Rates (Hz)	Receivers	Reduced	Steps with skips	Steps not heard
2026-10-07	20:02	night	48	`lib-mesh-bench-2026-10-07-07`	4	25·250	0	0	0	0
2026-10-07	22:19	night	48	`matrix-ladder-3h-night-2026-10-06-07`	11	25·50·100·250·500	6	648 on 6	0	0
2026-10-01	22:17	night	48	`matrix-ladder-3h-night-2026-09-30-03`	11	25·50·100·250·500	6	648 on 6	0	0
2026-09-19	15:07	day	48	`matrix-ladder-3h-weekend-2026-09-19-05`	11	25·50·100·250·500	6	648 on 6	0	0
2026-09-18	20:08	night	48	`matrix-ladder-3h-night-2026-09-18-07`	11	25·50·100·250·500	6	648 on 6	0	0
2026-09-16	15:08	day	48	`matrix-ladder-3h-day-2026-09-16-05`	11	25·50·100·250·500	6	540 on 5	0	0
2026-09-11	10:32	day	48	`lib-doppler-ladder-2026-09-11-06`	5	250·125·60·30·90	8	78 on 8	0	0
2026-09-09	07:08	day	48	`lib-doppler-ladder-2026-09-09-04`	5	250·90·45	9	61 on 9	0	0
2026-09-05	21:37	night	6	`lib-rate-ladder-6-2026-09-05-02`	8	50·100·250·500·25	9	164 on 9	0	4
2026-09-04	08:19	day	48	`lib-rate-ladder-48-day-2026-09-04-09`	10	25·50·100·250·500	9	270 on 9	0	0
2026-09-02	07:04	day	48	`lib-rate-ladder-48-day-2026-09-02-07`	9	25·50·100·250·500	9	266 on 9	0	0
2026-09-02	23:54	night	6	`lib-rate-ladder-6-2026-09-01-04`	10	25·50·100·250·500	9	296 on 9	1	6
2026-09-01	20:04	night	11	`lib-rate-ladder-24-2026-09-01-02`	10	25·50·100·250·500	9	296 on 9	1	5
2026-08-31	01:09	night	6	`lib-rate-ladder-6-2026-08-30-05`	3	25·50·100	9	45 on 9	1	0
2026-08-31	23:53	night	11	`lib-rate-ladder-24-2026-08-30-04`	10	25·50·100·250·500	9	297 on 9	0	5
2026-08-30	20:03	night	48	`lib-rate-ladder-48-2026-08-30-02`	10	25·50·100·250·500	9	297 on 9	0	0
2026-08-26	21:12	night	11	`lib-rate-ladder-24-2026-08-26-02`	10	25·50·100·250·500	9	297 on 9	1	4
2026-08-26	20:03	night	6	`lib-rate-ladder-6-2026-08-26-01`	10	25·50·100·250·500	9	292 on 9	0	6
2026-08-26	00:13	night	11	`lib-rate-ladder-24-2026-08-25-03`	10	25·50·100·250·500	9	297 on 9	0	7
2026-08-26	23:03	night	6	`lib-rate-ladder-6-2026-08-25-02`	10	25·50·100·250·500	9	297 on 9	0	6
2026-08-25	23:53	night	11	`lib-rate-ladder-24-2026-08-24-03`	10	25·50·100·250·500	9	293 on 9	1	5
2026-08-25	22:43	night	6	`lib-rate-ladder-6-2026-08-24-02`	10	25·50·100·250·500	9	293 on 9	0	6
2026-08-23	03:06	day	48	`lib-rate-ladder-48-2026-08-22-02`	10	25·50·100·250·500	8	264 on 8	0	0
2026-08-20	19:56	day	48	`rate-ladder-48-01`	41	25·50·100·250·500	9	839 on 9	0	0
2026-08-16	06:58	day	11	`monad01-ch11-20260816-0858`	11	5·10·25·50·100	5	3615 on 5	0	10

Scope of inference. One ladder is one draw of the channel: its ten steps are paired on the same hour, room and roster, so a step against a step is measured, instrument only. A night ladder against a day ladder holds everything fixed but the hour and the people in the building, which is the contrast the day arm was added for. Two ladders on two different days are observed, not measured.