Currently,

• We have a sub-type of BroadcastService called RadioBroadcastService.
• callSign lists RadioBroadcastService as a type where it is expected.

https://schema.org/callSign

I propose we expand the domain to also anticipate BroadcastService and Vehicle

For examples see Wikidata

SELECT DISTINCT ?x ?tLabel WHERE { 
  ?x wdt:P2317 ?cs.
  ?x wdt:P31 ?t .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en" }
}
ORDER BY ?tLabel