Simplified WSPR code

Simplified C snippet for generating WSPR sequences:

#include <stdio.h>

void main(){

#ifndef TEXTMSG
   // pack call in n1
   static char c[6]=" K1JT "; //call
   // all must be in uppercase
   // char at position 3 must be last digit of call prefix
   // left and right idented with space characters
   unsigned long n1;
   n1=(c[0]>='0'&&c[0]<='9'?c[0]-'0':c[0]==' '?36:c[0]-'A'+10);
   n1=36*n1+(c[1]>='0'&&c[1]<='9'?c[1]-'0':c[1]==' '?36:c[1]-'A'+10);
   n1=10*n1+c[2]-'0';
   n1=27*n1+(c[3]==' '?26:c[3]-'A');
   n1=27*n1+(c[4]==' '?26:c[4]-'A');
   n1=27*n1+(c[5]==' '?26:c[5]-'A');

   // pack grid, dbm in n2 
   static int lon = 5;   //degrees longitude east  -74       5
   static int lat  = 51;   //degrees latitude north  40      51

   int ng = 90*(180-lon+(lon<0?1:0) ) + lat;
   static int dbm = 33;    //EIRP dBm  (0<=dbm<=60)
   // must be in set {0,3,7,10,13,17,20,23,27,30,33,37,40,43,47,50,53,57,60}
   unsigned long n2=(ng<<7)|(dbm+64);
#else
   unsigned char msg[8] = "HI W0RLD";
   // pack text
   unsigned long long dn=0;
   int y;
   for(y=0;y!=8;y++){
      unsigned char c = msg[y];
      dn = 41*dn + (c>='0'&&c<='9'?c-'0': c>='A'&&c<='Z'?c-'A'+10: 
c=='+'?37: c=='.'?38: c=='/'?39: c=='?'?40: 36);
   }
   unsigned int ng=dn&0x7fff;
   unsigned long n1=dn>>15;
   int ntype=-57;  //plain text
   unsigned long n2=ng<<7|(ntype+64);
#endif

   // pack n1,n2 into 50 bits
   char packed[11] = {n1>>20, n1>>12, n1>>4, (n1&0x0f)<<4|(n2>>18)&0x0f, 
n2>>10, n2>>2, (n2&0x03)<<6, 0, 0, 0, 0};

   // Convolutional encoder for a K=32, r=1/2 code.
   // Layland-Lushbaugh polynomials for a K=32, r=1/2 convolutional code
   int k = 0;
   int i,j,p;
   int nstate = 0;
   unsigned char symbol[176];
   for(j=0;j!=sizeof(packed);j++){
      for(i=7;i>=0;i--){
         unsigned long poly[2] = { 0xf2d05351L, 0xe4613c47L };
         nstate = (nstate<<1) | ((packed[j]>>i)&1);
         for(p=0;p!=2;p++){   //convolve
            unsigned long n = nstate & poly[p];
            // even := parity(n)
            int even = 0;
            while(n){
               even = 1 - even;
               n = n & (n - 1);
            }
            symbol[k] = even;
            k++;
         }
      }
   }

   // Interleave symbols
   unsigned char symbol2[162];
   for(i=0;i!=162;i++){
      // j0 := bit reversed_values_smaller_than_161[i]
      unsigned char j0;
      p=-1;
      for(k=0;p!=i;k++){
         for(j=0;j!=8;j++)   // j0:=bit_reverse(k)
            j0 = ((k>>j)&1) | (j0<<1);
         if(j0<162)
          p++;
      }
      symbol2[j0]=symbol[i]; //interleave
   }

   // Sync vector 162 bits
   const unsigned char npr3[162] = {
      1,1,0,0,0,0,0,0,1,0,0,0,1,1,1,0,0,0,1,0,0,1,0,1,1,1,1,0,0,0,0,0,
      0,0,1,0,0,1,0,1,0,0,0,0,0,0,1,0,1,1,0,0,1,1,0,1,0,0,0,1,1,0,1,0,
      0,0,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0,1,0,1,1,0,0,0,1,1,0,1,0,1,0,
      0,0,1,0,0,0,0,0,1,0,0,1,0,0,1,1,1,0,1,1,0,0,1,1,0,1,0,0,0,1,1,1,
      0,0,0,0,0,1,0,1,0,0,1,1,0,0,0,0,0,0,0,1,1,0,1,0,1,1,0,0,0,1,1,0,
      0,0 };
   for(i=0;i!=162;i++){
      printf("symbol[%u]=%u\n", i, symbol2[i]);
      symbol2[i] = npr3[i] | symbol2[i]<<1;
   }

   // Modulate
   FILE* pf = fopen("a.au", "wb");
   fputc(0x2e,pf); //.au magic number
   fputc(0x73,pf);
   fputc(0x6e,pf);
   fputc(0x64,pf);
   fputc(0x00,pf); //offset
   fputc(0x00,pf);
   fputc(0x00,pf);
   fputc(24,pf);
   fputc(0xff,pf); //size
   fputc(0xff,pf);
   fputc(0xff,pf);
   fputc(0xff,pf);
   fputc(0x00,pf); //encoding
   fputc(0x00,pf);
   fputc(0x00,pf);
   fputc(0x03,pf);
   fputc(0x00,pf); //samplerate
   fputc(0x00,pf);
   fputc(0x2e,pf);
   fputc(0xe0,pf);
   fputc(0x00,pf); //channels
   fputc(0x00,pf);
   fputc(0x00,pf);
   fputc(0x01,pf);

   const int nmax=120*12000;
   double tsymbol=8192.0/12000.0;
   double dt=1.0/12000.0;
   double f0=1500;
   double dfgen=12000.0/8192.0;
   double t=0;
   double dphi;
   double phi=0;
   double dj0=0;
   for(i=0; i!=nmax; i++){
      t=t+dt;
      j=(int)(t/tsymbol)+1;
      if(j!=dj0){
         double f=f0+dfgen*(symbol2[j]-1.5);
         dj0=j;
         dphi=2*3.14*dt*f;
      }
      phi=phi+dphi;
      int wave=32767.0*sin(phi);
      fputc((wave>>8)&0xff,pf);
      fputc(wave&0xff,pf);
   }
   fclose(pf);
}