my kid wanted it to say point between the groupings, which is the speech engine, so this may sound different depending on your browser:

  <!DOCTYPE html><html><body><button onclick="f()">Start</button><script>
  function f(){with(window){
  a=new AudioContext;b=a.createBuffer(1,c=2*a.sampleRate,a.sampleRate);d=b.getChannelData(0);
  for(i=0;i<c;i++)d[i]=(Math.random()*2-1)*.4;
  e=a.createBufferSource();e.buffer=b;e.loop=1;g=a.createGain();g.gain.value=.05;
  e.connect(g).connect(a.destination);e.start();
  const l=n=>((n.match(/[A-Z]/g)||[]).length==1&&(n[0].match(/[A-Z]/g)||[]).length==1);
  setInterval(()=>{s=Object.getOwnPropertyNames(globalThis).filter(l).sort(()=>.5-Math.random())[0];
  if(Math.random()>.3){
    n=String(Math.ceil(Math.random()*1e4).toString().padStart(4,'0'));
    s=n[0]+'. '+n[1]+'. point. '+n[2]+'. '+n[3]+'.';
  }
  m=new SpeechSynthesisUtterance;m.text=s;
  v=speechSynthesis.getVoices();m.lang=v[(Math.random()*v.length)|0].lang;
  m.rate=Math.random();m.pitch=Math.random()*2;speechSynthesis.speak(m);},866);
  //m.rate=1.7;m.pitch=2;speechSynthesis.speak(m);},866);
  }}</script></body></html>

the comment at the end can be switched with the preceeding line so it sounds like he wanted it to (high pitched and fast, please) <1kb

and i got something stuck in my craw about noise so here's one with more accurate noise:

  <!DOCTYPE html><html><body><button onclick="f()">Start</button><script>
  function f(){with(window){
  a=new AudioContext;
  g=a.createGain();g.gain.value=.05; 
  h=a.createScriptProcessor(256,1,1);p=0;
  h.onaudioprocess=e=>{
    b=e.outputBuffer.getChannelData(0);
    for(i=0;i<b.length;i++)b[i]=p+=(Math.random()*2-1)/10;
  };
  h.connect(g).connect(a.destination);
  const l=n=>((n.match(/[A-Z]/g)||[]).length==1&&(n[0].match(/[A-Z]/g)||[]).length==1);
  setInterval(()=>{
    s=Object.getOwnPropertyNames(globalThis).filter(l).sort(()=>.5-Math.random())[0];
    if(Math.random()>.3){
      n=String(Math.ceil(Math.random()*1e4).toString().padStart(4,'0'));
      s=n[0]+'. '+n[1]+'. point. '+n[2]+'. '+n[3]+'.';
    }
    m=new SpeechSynthesisUtterance;m.text=s;
    v=speechSynthesis.getVoices();m.lang=v[(Math.random()*v.length)|0].lang;
    m.rate=Math.random();m.pitch=Math.random()*2;speechSynthesis.speak(m);
  },866);
  }}</script></body></html>

apologies to the HN servers for using 2kb to display these

i don't know javascript so apologies if i messed anything up (because it will eventually pop and click which is extremely accurate to numbers station reception but also crashes the page - audio stops.)