var db;			
 var range;
 var rangem;
 var rangea;
 var rangeb;
 var earth;
	var eirpahold;
	var eirpbhold;
	var avlinka;
	var avlinkb;
	var mw;	
	var	w;	
	var	dbm;	
	var	dbw;	
	var	num;	
	var f;			
	var d;			
	
	

function round(number,places) {
	// rounding numbers
	places = (!places ? 2 : places);
	return Math.round(number*Math.pow(10,places))/Math.pow(10,places);
} 


function log10(x) {
	// Logging10
	return(Math.log(x) / Math.log(10));
}



function dbm_mw(dbm) {
document.conv.Tmw.value=Math.pow(10,dbm/10);
}

function mw_dbm(w) {
document.conv.Tdb.value=10*Math.log(w*1000)/Math.log(10);
}



function calculatefz() {

d1=parseFloat(document.fres.dist.value);
d2=parseFloat(document.fres.link.value)-d1;
d3=parseFloat(document.fres.link.value)/2;
w=parseFloat(document.fres.wavel.value);

document.fres.T4.value=round(0.6*Math.sqrt(w*d1*d2/(d1+d2)),2);
document.fres.T3.value=round(0.6*Math.sqrt(w*d3*d3/(d3+d3)),2);

}

function diffraction_compute() {

h=parseFloat(document.diffraction.h.value);
d1=parseFloat(document.diffraction.D1.value);
d2=parseFloat(document.diffraction.D2.value);
v=h*Math.sqrt(2*(d1+d2)/(0.12*d1*d2));
document.diffraction.loss.value=20*Math.log(0.225/v)/Math.log(10);
}

function calclink() {
eirpahold=parseFloat(document.calculated.SAP.value)+parseFloat(document.calculated.SAG.value) -parseFloat(document.calculated.SAA.value) -(parseFloat(document.calculated.SAC.value)*parseFloat(document.calculated.SAL.value)) ;
document.calculated.EIRPA.value=eirpahold;
eirpbhold=parseFloat(document.calculated.SBP.value)-(parseFloat(document.calculated.SBC.value)*parseFloat(document.calculated.SBL.value))-parseFloat(document.calculated.SBA.value) +parseFloat(document.calculated.SBG.value);
document.calculated.EIRPB.value=eirpbhold
if (eirpahold>20) {document.calculated.EIRPA.style.color="#FF0000";} else {document.calculated.EIRPA.style.color="#000000";}

if (eirpbhold>20) {document.calculated.EIRPB.style.color="#FF0000";} else {document.calculated.EIRPB.style.color="#000000";}
avlinka=eirpahold-10-parseFloat(document.calculated.SBS.value)-(parseFloat(document.calculated.SBC.value)*parseFloat(document.calculated.SBL.value))-parseFloat(document.calculated.SBA.value) +parseFloat(document.calculated.SBG.value);
;

avlinkb=eirpbhold-10-parseFloat(document.calculated.SAS.value)+parseFloat(document.calculated.SAG.value) -parseFloat(document.calculated.SAA.value) -(parseFloat(document.calculated.SAC.value)*parseFloat(document.calculated.SAL.value)) ;
cst=-40.4;
rangab=Math.pow(10,(cst+avlinka)/20)/1000;
rangba=Math.pow(10,(cst-avlinkb)/20)/1000;


if (rangab>rangba) {range=rangab;} else {range=rangba;}
document.calculated.RANGE.value=round(range,2);
rangem=range*500;
document.calculated.fres.value=round(0.6*Math.sqrt(0.12*rangem*rangem/(rangem+rangem)),2);
earth = round((Math.pow(range,2)/(8*6378)) * 10000/3.1,2);
document.calculated.earth.value=earth ;
document.calculated.height.value=earth+parseFloat(document.calculated.fres.value);

}

function calclinka() {
eirpahold=parseFloat(document.calculateda.SAP.value)+parseFloat(document.calculateda.SAG.value) -parseFloat(document.calculateda.SAA.value) -(parseFloat(document.calculateda.SAC.value)*parseFloat(document.calculateda.SAL.value)) ;
document.calculateda.EIRPA.value=eirpahold;
eirpbhold=parseFloat(document.calculateda.SBP.value)-(parseFloat(document.calculateda.SBC.value)*parseFloat(document.calculateda.SBL.value))-parseFloat(document.calculateda.SBA.value) +parseFloat(document.calculateda.SBG.value);
document.calculateda.EIRPB.value=eirpbhold
if (eirpahold>20) {document.calculateda.EIRPA.style.color="#FF0000";} else {document.calculateda.EIRPA.style.color="#000000";}

if (eirpbhold>20) {document.calculateda.EIRPB.style.color="#FF0000";} else {document.calculateda.EIRPB.style.color="#000000";}
avlinka=eirpahold-10-parseFloat(document.calculateda.SAS.value)-(parseFloat(document.calculateda.SBC.value)*parseFloat(document.calculateda.SBL.value))-parseFloat(document.calculateda.SBA.value) +parseFloat(document.calculateda.SBG.value);
;

avlinkb=eirpbhold-10-parseFloat(document.calculateda.SAS.value)+parseFloat(document.calculateda.SAG.value) -parseFloat(document.calculateda.SAA.value) -(parseFloat(document.calculateda.SAC.value)*parseFloat(document.calculateda.SAL.value)) ;
cst=-40.4;
rangab=Math.pow(10,(cst+avlinka-7.8)/20)/1000;
rangba=Math.pow(10,(cst-avlinkb-7.8)/20)/1000;


if (rangab>rangba) {range=rangab;} else {range=rangba;}
document.calculateda.RANGE.value=round(range,2);
rangem=range*500;
document.calculateda.fres.value=round(0.6*Math.sqrt(0.056*rangem*rangem/(rangem+rangem)),2);
}