The ARCADE 2 radio background runs several times brighter than the integrated emission of all known source populations (Fixsen 2011; Seiffert 2011), and every repair is squeezed: fainter sources overproduce the counts, diffuse mechanisms violate gamma-ray budgets, and dark-sector emitters are tuned constructions (Fornengo 2014). The counted sky does not add up to the measured one.
The model's radio inventory descends from its galaxy and AGN demography: every photon must come from star formation or accretion in hierarchically grown structures, with the populations counted and the budget closed. An excess of this size means a major emitting population the demography never produced, and the standard inventory has no room to hide one.
SCT's emitting demography is larger than the standard model's for the same reason across the background sectors: the cascade seeded compact objects directly, across a mass spectrum and spatial distribution set by deposition geometry rather than stellar evolution (P46, P25), and accretion onto that population radiates in radio with synchrotron efficiency over cosmic time. The seeded emitters live preferentially along the deposited web (P34), off-nuclear and in hosts too faint for source catalogs, which is precisely where an excess background hides without violating source counts: many faint distributed emitters rather than few bright countable ones.
The timing fits where the standard inventory fails: a seeded population radiating from the earliest epochs supplies the high-redshift radio background the EDGES absorption depth independently wants, without waiting for hierarchical assembly to build the emitters. This is the same cascade-stocked inventory carrying the FRB second pedigree (recid 153), the FBOT engines (recid 149), and the X-ray-coherent infrared background (recid 156), read at low frequency; one undercounted demography, four background anomalies. The seeding mechanics are in Paper 4, From Chaos To Collisothermal Cosmogenesis, with the compact-object framework in Paper 9, From Chaos To Collapse Proof.
Keystone economy: P46 supplies the emitters, P34 distributes them below the counting threshold. The budget violation is an inventory omission.
SKA depth carries the kill: if ultra-deep source counts resolve the ARCADE 2 excess into known population extrapolations after all, or conversely fail to find the predicted numerous faint distributed emitters along the web at the abundance the background requires, the seeded-demography reading fails. The timing half is separately exposed: 21-cm cosmology establishing that no enhanced radio background existed at high redshift would remove the early component the seeded population necessarily supplies.