In nearly every part of the world, some satellite carries NHK news.
The news are never scrambled - but otherwise Sumo mostly is.
The news schedule here is from JSTV.
on ASTRA in Europe, Central European (Summer) Time.
Wether in your area daily NHK Sumo coverage is included 
 - or maybe the Asahi TV Sumo Digest -
and at what conditions, you have to check for yourselves,
NHK news broadcasts are usually live or one hour behind.

You can watch the news on JSTV from ASTRA 1D, 10 773 GHz or digital 11.023 GHz. Horizontal polarization. 
Audio:
7.02 Stereo, Japanese only (or English in case of English news like
"Dayline Japan")
7.20 Bilingual, English sub channel (or Japanese with "Japan This Day")
7.38 Mono, English, sub channel empty

First Sumo results are on News7, bilingual (Mo-Fr, 12:00-12:35 CEST).
The sports corner usually is somewhere between :25 and :33,
While the Basho is going on, sumo is usually first.
2 to 4 bouts are shown (90% with Ozeki or Yokozuna), the complete Makunouchi results, sometimes interviews or an (Mihogaseki-)oyakata comment on one bout.
Those days when Sumo was in the headlines are scarce now. Mentioned at the beginning of the news is soccer now, but still mainly baseball.

News9, bilingual (Mo-Fr, 14:00-14:15),
has a short sports corner, mainly a repeat of News7, nearly never a different bout to be seen - but it happens.

NHK newswatch in English has a very short Sumo corner, showing the top results only and one bout near the end of the Mo-Fr 14:35-15:00 program.

News10 (Mo-Fr, 15:00-16:00, Japanese only)
usually also shows one or two different bouts.
The previous program News11 had an extensive analysis from Isenoumi-oyakata.
Background information on Sumo may be shown on some days, e. g. about building the Dohyo, doing the Shiko movement etc.
The quality of News10 in respect of sumo has still to be evaluated at their first basho coverage in May.

Ohayo Nippon (00:00-00:45), the morning news are also Japanese only.
They sometimes have a sumo special, like how is Mainoumi doing, or how much different Kimarite from Kyokushuzan, but mostly it is just one already shown bout of the day.
Last News11 female caster Aoyama is doing the sports corner. Sports is somewhere between :15 and :25.

Midday news (7:00-7:20) may only say something about newly
announced absence because of injury.
But on the day after the basho, the morning interview with the winner is shown. Between Basho, this programm may even carry more Sumo than the later news, e.g. on Banzuke presentation day, official training day, new entrant day.

On weekends:
News7 and 9 are shorter, no News10.
NHK weekly news on Saturday 7:15 - 8:00 have a recap of the week and sometimes even show new scenes. Weekly news for children on Sunday 9:03 - 9:35 mention Sumo occasionally.
Ohayo Nippon is only till 0:30 (Saturday) for Friday 24:00.

Other news usually don't cover Sumo !

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On the scrambled side (except for those who pay the big JSTV fee):

NHK Makunouchi Sumo so far was daily from around 14:30 to 15:45 CEST (after the results on News7 and 9), bilingual: you may still have the chance to hear KONISHIKI (or Junko Kubo) in English on one day.
The coverage starts after the first bouts.
Just hearing the full sound of Sumo is better than nothing.

Some (Oguruma-)oyakata comments can be heard on the Saturday 19:30-20:00 and Sunday 19:00-20:00 Sports magazines.