SSRF-LiteChicago north side receive site (approx)
loc_chi_north_rx
SSRF-Lite reference data
Chicago DMR (monitor-confirmed, licensee unidentified)
Business / itinerant
Channels
5 assignments, sorted by frequency. Frequency is what your radio receives; input is what it transmits on for repeaters.
| Freq (MHz) | Input (MHz) | Mode | Tone / CC | Name | Usage | Callsign | Location | Service | Notes |
|---|---|---|---|---|---|---|---|---|---|
| 452.3875 | DMR | CC11 TS1,2 | CHI DMR 452 3875 | repeater | Chicago north side receive site (approx) | Business / itinerant | Monitor-confirmed Motorola Capacity Plus system, frequency confirmed by exact-channel dwell 2026-09-27. Still no talkgroup captured: 1.8 h of camps plus a dedicated continuous camp produced 14,892 CSBK and 8,173 Cap+ indications but zero decodable voice headers. On Capacity Plus the payload follows the rest slot as it moves, so a single fixed receiver on one channel sees control traffic almost exclusively - the earlier "traffic volume was too low" reading was wrong about the cause. Harvesting talkgroups here needs a trunk-following receiver driven by an LSN-to-frequency channel map, which does not exist yet. | ||
| 453.5875 | DMR | CC9 TS1 | CHI DMR 453 5875 | repeater | Chicago north side receive site (approx) | Business / itinerant | Monitor-confirmed DMR repeater output, timeslot 1 only, single talkgroup (TG 1). Downlink only - the uplink was never observed, so tx.freq_mhz is null rather than guessed from a standard Part 90 offset. Traffic carries the privacy bit, so this entry is a frequency and identity reference, not a listenable channel. | ||
| 462.1375 | DMR | CC3 TS1 | CHI DMR 462 1375 | repeater | Chicago north side receive site (approx) | Business / itinerant | Monitor-confirmed DMR repeater output. Single-talkgroup operation (TG 50) on TS1. | ||
| 464.9750 | DMR | CC11 TS1,2 | CHI DMR 464 975 | repeater | Chicago north side receive site (approx) | Business / itinerant | Monitor-confirmed DMR repeater output, timeslot 2 - talkgroups 1 and 1101, which together carry 80% of all voice traffic observed on this chain. | ||
| 464.9750 | DMR | CC11 TS1,2 | CHI DMR 464 975 TS1 | repeater | Chicago north side receive site (approx) | Business / itinerant | Same transmitter as asgn_chi_dmr_464_975, split out as a separate assignment for timeslot 1, which carries only TG 200 (1.0% of bursts, 5 radios). A receiver can only sit on one slot at a time, so monitoring both slots needs two channels. |
Sites
1 location.
Organizations
Chicago DMR (monitor-confirmed, licensee unidentified)
org_chi_dmr_monitored
Talkgroups & contacts
| Name | Kind | ID | Notes |
|---|---|---|---|
| 464.9750 TG 1 | Group | 1 | 41.9% of voice-header bursts on this chain (3,152 of 7,524 after folding single-bit corruptions back to source), 17 distinct radio IDs observed. |
| 464.9750 TG 1101 | Group | 1101 | 38.1% of voice-header bursts (2,865 after bit-flip folding), 15 distinct radio IDs. Most frequent source IDs 505 and 551. |
| 464.9750 TG 200 | Group | 200 | 1.0% of voice-header bursts (72), 5 distinct radio IDs. The only group seen on timeslot 1 on this chain. |
| 462.1375 TG 50 | Group | 50 | Primary and effectively sole talkgroup on this chain - 92.5% of voice-header bursts (9,412 of 10,181), 38 distinct radio IDs, all on timeslot 1. Remaining traffic is the DMR All Call broadcast address (16777215, 6.2%). |
| 453.5875 TG 1 | Group | 1 | Sole talkgroup observed on this chain - 967 of 1,319 clean voice headers carried TG 1 exactly, rising to 1,140 once values within two bit-flips are folded back (262145, 524289, 1048577, 131073 and 8388609 are each a single high-order bit set on top of 1). Raw decoder output listed 285 distinct radio IDs, but almost all are corruptions; the coherent fleet is a tight block in the 315-381 range, most active being 317 (272 headers), 323 (138), 315 (99), 343 (85), 342 (71), 373 (68) and 379 (63). Traffic is encrypted, so talkgroup function cannot be characterised beyond the identifiers themselves. |
Sources
Where this data came from. Verify on the air before relying on it.
- Chicago Offline UHF monitoring survey - RTL-SDR + dsd-fme, Chicago north side receive site. 2026-08-19/27 trigger-gated capture (2,059 decoder logs, 129 h dwell), talkgroup extraction 2026-09-25, live re-confirmation 2026-09-25. · accessed 2026-09-25
- Chicago Offline UHF monitoring survey - continuous run 2026-09-27. Two RTL-SDR receivers at the same Chicago north side site: one cycling probe/camp across five confirmed UHF DMR channels, one dedicated continuous camp on 452.3875 from 19:23 local. 5.2 h of targeted dwell across the three chains updated here; link-control extraction from 558 dsd-fme camp logs. · accessed 2026-09-27