The most common and most likely answer to this crossword clue is the 6 letter word RELAYS
I've seen this crossword clue in Financial Times
R
E
L
A
Y
S
Buddy explains!

The straight part
We know that "Broadcasts/races" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case broadcasts/races = relays.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RELAYS mean?
RELAYS verb- To lay (for example, flooring or railroad track) again.
- A new set of hounds.
- A new set of horses kept along a specific route so that they can replace animals that are tired.
- (by extension) A new set of anything.
- A series of vehicles travelling in sequence.
- A track and field discipline where runners take turns in carrying a baton from start to finish. Most common events are 4x100 meter and 4x400 meter competitions.
- An electrical actuator that allows a relatively small electrical voltage or current to control a larger voltage or current.
- To release a new set of hounds.
- To place (people or horses) in relays, such that one can take over from another.
- To take on a new relay of horses; to change horses.
- To pass on or transfer (information).