var freq2ch="";
function show_freq_num()
{
// Keyed in frequency reflects
// L0-123456789-123456789-12345
// L1 frequency ### Mhz matches
// L2 ~ RF Ch. ##
// L3 A VHF / UHF TV channel
// L4 Slots to ###.25 Mhz Analogue
// L5 _-_-_-_  ###.50 Mhz Digital
// L6  ### ### Khz or ### ### ### hz
// L7 scrolling messages

// Default messages
var align="n";
var m="TV Channel ";
var m0="Analog only - VHF Lo";
var m1="- Official frequency may vary +/-0.125Mhz, your TV receiver will auto tune, set to one of these numbers";
var m2="TV Channel ";
var m3="VHF Band ";
var m4="UHF Band ";
var m6="Analog ";
var m7="Digital ";
var m9="undefined ";
var mB="Hyper ";
var mC=" tune to the ";
var mD="DTV Ch. does NOT equal RF Ch."
var mH=" hz ";
var mK=" Khz ";
var mZ=" Mhz ";
var m10=" <abbr title='copyright'>(C)</abbr> VK3KHB.GAK.NET.AU <abbr title='Interlectual Property'>(IP)</abbr>";
var m12="Ham Radio TV - UHF ";
var m13="Community TV - UHF ";

var fm1="<marquee scrollamount=\"2\" width=\"156\">"+m10+"</marquee>";
var fm2=" Mhz<abbr title=\""+fm1+"\"> DiGiTaL</abbr>";

var $onetxt;
var fq_fA=0;
var fq_fD=0;
var fq_fDk;
var fq_fDh;
var ch_n="";  
var fq_n=prompt("Mhz Frequency to RF Channel Calculator\nplease enter a Frequency # 45 - 820","444");
 if (fq_n!=null && fq_n!="")
  {
  fq_n=fq_n.toUpperCase();
  if (fq_n>820) { alert("Error! value is too high"); return;}
  if (fq_n<0) { alert("Error! value is too low"); return;}
  // convert TV text IDs to numbers
  if (fq_n.match( "ABC" )) { fq_n="226"; }
  if (fq_n.match("SEVEN")) { fq_n="177"; }
  if (fq_n.match( "NINE")) { fq_n="191"; }
  if (fq_n.match( "TEN" )) { fq_n="212"; }
  if (fq_n.match( "ATV" )) { fq_n="444"; }
  if (fq_n.match( "SBS" )) { fq_n="536"; }
  if (fq_n.match( "CTV" )) { fq_n="550"; }
  if (fq_n.match( "D44" )) { fq_n="578"; }
  if (fq_n.match( "5A"  )) { fq_n="140"; }
  if (fq_n.match( "9A"  )) { fq_n="205"; }
  if (isNaN(fq_n)) { alert("Error! "+fq_n+" is not known"); return;}
  // round down any decimal points
  fq_n=(Math.floor(fq_n)); 
  // below tv frequencies are MF and HF radio
  if (fq_n>-1 && fq_n<45) { fq_fD=0; ch_n=" none"; m=m9; }
  // Calculate channel # from freq. or kludge it!
  if (fq_n>44 && fq_n<53) { fq_fD=0.0; fq_fA=46.25; ch_n="00"; m=m0;}
  if (fq_n>52 && fq_n<64) { fq_fD=0.0; fq_fA=57.25; ch_n="01"; m=m0;}
  if (fq_n>63 && fq_n<71) { fq_fD=0.0; fq_fA=64.25; ch_n="02"; m=m0;}
  if (fq_n>70 && fq_n<85) { fq_fD=0.0; ch_n=" none"; m=m9; }
  if (fq_n>84 && fq_n<93) { fq_fD=0.0; fq_fA=86.25; ch_n="03"; m=m0;}
  if (fq_n>92 && fq_n<102) { fq_fD=0.0; fq_fA=95.25; ch_n="04"; m=m0;}
  if (fq_n>101 && fq_n<109) { fq_fD=0.0; fq_fA=102.25; ch_n="05"; m=m0;}
  if (fq_n>108 && fq_n<137) { ch_n=(Math.floor(1+(fq_n-105)/7)); fq_fD=(107.5+((ch_n-1)*7)); ch_n="S_"+ch_n; m=m+mB+m3;}
  if (fq_n>136 && fq_n<145) { fq_fD=0.0; fq_fA=138.25; ch_n="5a"; m=m0;}
  if (fq_n>144 && fq_n<147) { fq_fD=0.0; ch_n=" none"; m="2mtr HAM Radio VHF Band";}
  if (fq_n>146 && fq_n<174) { ch_n=(Math.floor(7+(fq_n-147)/7)); fq_fD=(149.5+((ch_n-7)*7)); ch_n="S"+ch_n; m=m+mB+m3;}
  if (fq_n>173 && fq_n<181) { fq_fD=177.5; ch_n="06"; m=m3+m;}
  if (fq_n>180 && fq_n<188) { fq_fD=184.5; ch_n="07"; m=m3+m;}
  if (fq_n>187 && fq_n<195) { fq_fD=191.5; ch_n="08"; m=m3+m;}
  if (fq_n>194 && fq_n<202) { fq_fD=198.5; ch_n="09"; m=m3+m;}
  if (fq_n>201 && fq_n<209) { fq_fD=205.5; ch_n="9a"; m=m3+m;}
  if (fq_n>208 && fq_n<216) { fq_fD=212.5; ch_n="10"; m=m3+m;}
  if (fq_n>215 && fq_n<223) { fq_fD=219.5; ch_n="11"; m=m3+m;}
  if (fq_n>222 && fq_n<231) { fq_fD=226.5; ch_n="12"; m=m3+m;}
  if (fq_n>230 && fq_n<443) { ch_n=(Math.floor(11+(fq_n-231)/7)); fq_fD=(233.5+((ch_n-11)*7)); if(ch_n>20) {ch_n="S_"+ch_n; m=m+mB+m4;} else {ch_n="S_"+ch_n; m=m+mB+m3;}}
  if (fq_n>442 && fq_n<451) { fq_fD=446.5; ch_n="aTV (350 / S41)"; m=m12;}
  if (fq_n>450 && fq_n<478) { ch_n=(Math.floor(42+(fq_n-448)/7)); fq_fD=(450.5+((ch_n-42)*7)); ch_n="S_"+ch_n; m=m+mB+m4;}
  if (fq_n>477 && fq_n<821) { ch_n=(Math.floor(21+(fq_n-478)/7)); fq_fD=(480.5+((ch_n-21)*7)); m=m4+m;}
  // Calculate analog freq. kludge vhf lo ch#
  if (fq_fD>2.25 ) { fq_fA=fq_fD-2.25; fq_fDk=(fq_fD*1000); fq_fDh=(fq_fDk*1000);}
  if (fq_fD<2.25 ) { fq_fDk=(fq_fA*1000); fq_fDh=(fq_fDk*1000);}

 // output preformat ($onetxt.small(0))
  L0="123456789-123456789-1234<br>";
  L1="Frequency "+fq_n+" Mhz matches<br>";
  L2="~ RF CH. "+ch_n+"<br>";
  L3=m+"<br>";
  L4="Slots to "+fq_fA+" Mhz A<br>";
  L5="_-_-_ or "+fq_fD+"0 Mhz D<br>";
  L6=fq_fDk+" Khz or<br>"+fq_fDh+" hz<br><br>";
  L7=(fm1.small(0))+"<br>";
 //
  if (align=="Y") {$onetxt=L0+L1+L2+L3+L4+L5+L6+L7+L0;}
else {$onetxt=L1+L2+L3+L4+L5+L6+L7;}
document.getElementById("txtone").style.backgroundColor="blue";
document.getElementById("txtone").style.border="1px solid black";
document.getElementById("txtone").style.color="white";
document.getElementById("txtone").innerHTML=$onetxt;
 }
}
// js code from vk3khb.gak.net.au March2010