diff --git a/advanced.js b/advanced.js
index 75e7eb5..7207687 100644
--- a/advanced.js
+++ b/advanced.js
@@ -1,6 +1,6 @@
 const {ipcRenderer} = require('electron');
 
-var cfg = {};
+let cfg = {};
 
 const bt_save=document.querySelector("#save");
 
diff --git a/main.js b/main.js
index 4a273f3..995a307 100644
--- a/main.js
+++ b/main.js
@@ -17,10 +17,10 @@ const DemoAdif='<call:5>DJ7NT <gridsquare:4>JO30 <mode:3>FT8 <rst_sent:3>-15 <rs
 
 if (require('electron-squirrel-startup')) app.quit();
 
-var udp = require('dgram');
+const udp = require('dgram');
 
-var q={};
-var defaultcfg = {
+let q={};
+let defaultcfg = {
 	wavelog_url: "https://log.jo30.de/index.php",
 	wavelog_key: "mykey",
 	wavelog_id: "0",
@@ -112,8 +112,8 @@ ipcMain.on("resize", async (event,arg) => {
 });
 
 ipcMain.on("get_config", async (event, arg) => {
-	var storedcfg = storage.getSync('basic');
-	var realcfg={};
+	let storedcfg = storage.getSync('basic');
+	let realcfg={};
 	if (!(storedcfg.wavelog_url) && !(storedcfg.profiles)) { storedcfg=defaultcfg; }	// Old config not present, add default-cfg
 	if (!(storedcfg.profiles)) {	// Old Config without array? Convert it
 		(realcfg.profiles = realcfg.profiles || []).push(storedcfg);
@@ -295,13 +295,13 @@ function send2wavelog(o_cfg,adif, dryrun = false) {
 	clpayload.station_profile_id=o_cfg.wavelog_id.trim();
 	clpayload.type='adif';
 	clpayload.string=adif;
-	postData=JSON.stringify(clpayload);
+	const postData=JSON.stringify(clpayload);
 	let httpmod='http';
 	if (o_cfg.wavelog_url.toLowerCase().startsWith('https')) {
 		httpmod='https';
 	}
 	const https = require(httpmod);
-	var options = {
+	const options = {
 		method: 'POST',
 		timeout: 5000,
 		rejectUnauthorized: false,
@@ -313,7 +313,7 @@ function send2wavelog(o_cfg,adif, dryrun = false) {
 	};
 
 	return new Promise((resolve, reject) => {
-		rej=false;
+		let rej=false;
 		let result={};
 		let url=o_cfg.wavelog_url + '/api/qso';
 		if (dryrun) { url+='/true'; }
@@ -327,7 +327,7 @@ function send2wavelog(o_cfg,adif, dryrun = false) {
 			const body = [];
 			res.on('data', (chunk) => body.push(chunk));
 			res.on('end', () => {
-				var resString = Buffer.concat(body).toString();
+				const resString = Buffer.concat(body).toString();
 				if (rej) {
 					if (resString.indexOf('html>')>0) {
 						resString='{"status":"failed","reason":"wrong URL"}';
@@ -370,15 +370,15 @@ ports.forEach(port => {
 	});
 
 	WServer.on('message',async function(msg,info){
-		parsedXML={};
-		adobject={};
+		let parsedXML={};
+		let adobject={};
 		if (msg.toString().includes("xml")) {	// detect if incoming String is XML
 			try {
 				xml.parseString(msg.toString(), function (err,dat) {
 					parsedXML=dat;
 				});
 				let qsodatum = new Date(Date.parse(parsedXML.contactinfo.timestamp[0]+"Z")); // Added Z to make it UTC
-				qsodat=fmt(qsodatum);
+				const qsodat=fmt(qsodatum);
 				if (parsedXML.contactinfo.mode[0] == 'USB' || parsedXML.contactinfo.mode[0] == 'LSB') {	 // TCADIF lib is not capable of using USB/LSB
 					parsedXML.contactinfo.mode[0]='SSB';
 				}
@@ -414,11 +414,11 @@ ports.forEach(port => {
 				return;
 			}
 		}
-		var plainret='';
+		let plainret='';
 		if (adobject.qsos.length>0) {
 			let x={};
 			try {
-				outadif=writeADIF(adobject);
+				const outadif=writeADIF(adobject);
 				plainret=await send2wavelog(defaultcfg.profiles[defaultcfg.profile ?? 0],outadif.stringify());
 				x.state=plainret.statusCode;
 				x.payload = JSON.parse(plainret.resString); 
@@ -470,9 +470,9 @@ function startserver() {
 			res.setHeader('Access-Control-Allow-Origin', '*');
 			res.writeHead(200, {'Content-Type': 'text/plain'});
 			res.end('');
-			let parts = req.url.substr(1).split('/'); 
-			let qrg = parts[0]; 
-			let mode = parts[1] || '';
+			const parts = req.url.substr(1).split('/');
+			const qrg = parts[0];
+			const mode = parts[1] || '';
 			if (Number.isInteger(Number.parseInt(qrg))) {
 				settrx(qrg,mode);
 			}
@@ -523,7 +523,7 @@ async function settrx(qrg, mode = '') {
 		avail_modes=await get_modes();
 	} catch(e) {
 		avail_modes=[];
-	} 
+	}
 	let to={};
 	to.qrg=qrg;
 	if (mode == 'cw') {
@@ -536,9 +536,9 @@ async function settrx(qrg, mode = '') {
 		}
 	}
 	if (defaultcfg.profiles[defaultcfg.profile ?? 0].flrig_ena) {
-		postData= '<?xml version="1.0"?>';
+		let postData= '<?xml version="1.0"?>';
 		postData+='<methodCall><methodName>main.set_frequency</methodName><params><param><value><double>' + to.qrg + '</double></value></param></params></methodCall>';
-		var options = {
+		let options = {
 			method: 'POST',
 			headers: {
 				'User-Agent': 'SW2WL_v' + app.getVersion(),
@@ -546,12 +546,12 @@ async function settrx(qrg, mode = '') {
 			}
 		};
 		let url="http://"+defaultcfg.profiles[defaultcfg.profile ?? 0].flrig_host+':'+defaultcfg.profiles[defaultcfg.profile ?? 0].flrig_port+'/';
-		x=await httpPost(url,options,postData);
+		let x=await httpPost(url,options,postData);
 
 		if (defaultcfg.profiles[defaultcfg.profile ?? 0].wavelog_pmode) {
 			postData= '<?xml version="1.0"?>';
 			postData+='<methodCall><methodName>rig.set_modeA</methodName><params><param><value>' + to.mode + '</value></param></params></methodCall>';
-			var options = {
+			options = {
 				method: 'POST',
 				headers: {
 					'User-Agent': 'SW2WL_v' + app.getVersion(),
@@ -579,13 +579,13 @@ async function settrx(qrg, mode = '') {
 
 function httpPost(url,options,postData) {
 	return new Promise((resolve, reject) => {
-		rej=false;
+		let rej=false;
 		let result={};
 		const req = http.request(url,options, (res) => {
 			let body=[];
 			res.on('data', (chunk) => body.push(chunk));
 			res.on('end', () => {
-				var resString = Buffer.concat(body).toString();
+				const resString = Buffer.concat(body).toString();
 				if (rej) {
 					reject(resString);
 				} else {
@@ -612,13 +612,13 @@ function httpPost(url,options,postData) {
 }
 
 function fmt(spotDate) {
-	retstr={};
-	d=spotDate.getUTCDate().toString();
-	y=spotDate.getUTCFullYear().toString();
-	m=(1+spotDate.getUTCMonth()).toString();
-	h=spotDate.getUTCHours().toString();
-	i=spotDate.getUTCMinutes().toString();
-	s=spotDate.getUTCSeconds().toString();
+	const retstr={};
+	const d=spotDate.getUTCDate().toString();
+	const y=spotDate.getUTCFullYear().toString();
+	const m=(1+spotDate.getUTCMonth()).toString();
+	const h=spotDate.getUTCHours().toString();
+	const i=spotDate.getUTCMinutes().toString();
+	const s=spotDate.getUTCSeconds().toString();
 	retstr.d=y.padStart(4,'0')+m.padStart(2,'0')+d.padStart(2,'0');
 	retstr.t=h.padStart(2,'0')+i.padStart(2,'0')+s.padStart(2,'0');
 	return retstr;
diff --git a/renderer.js b/renderer.js
index cef892d..723d4a1 100644
--- a/renderer.js
+++ b/renderer.js
@@ -7,9 +7,9 @@
 
 
 // Shorthand for document.querySelector.
-var cfg={};
-var active_cfg=0;
-var trxpoll=undefined;
+let cfg={};
+let active_cfg=0;
+let trxpoll=undefined;
 
 const {ipcRenderer} = require('electron')
 const net = require('net');
@@ -21,8 +21,8 @@ const bt_test=select("#test");
 const input_key=select("#wavelog_key");
 const input_url=select("#wavelog_url");
 
-var oldCat={ vfo: 0, mode: "SSB" };
-var lastCat=0;
+let oldCat={ vfo: 0, mode: "SSB" };
+let lastCat=0;
 
 $(document).ready(function() {
 
@@ -73,7 +73,7 @@ $(document).ready(function() {
 		cfg.profiles[active_cfg].wavelog_key=$("#wavelog_key").val().trim();
 		cfg.profiles[active_cfg].wavelog_id=$("#wavelog_id").val().trim();
 		cfg.profiles[active_cfg].wavelog_radioname=$("#wavelog_radioname").val().trim();
-		x=(ipcRenderer.sendSync("test", cfg.profiles[active_cfg]));
+		const x=(ipcRenderer.sendSync("test", cfg.profiles[active_cfg]));
 		if (x.payload.status == 'created') {
 			$("#test").removeClass('btn-primary');
 			$("#test").removeClass('btn-danger');
@@ -103,7 +103,7 @@ $(document).ready(function() {
 	window.onload = updateUtcTime;
 
 	$("#config-tab").on("click",function() {
-		obj={};
+		const obj={};
 		obj.width=430;
 		obj.height=550;
 		obj.ani=false;
@@ -111,7 +111,7 @@ $(document).ready(function() {
 	});
 
 	$("#status-tab").on("click",function() {
-		obj={};
+		const obj={};
 		obj.width=430;
 		obj.height=250;
 		obj.ani=false;
@@ -253,7 +253,7 @@ async function getInfo(which) {
 async function getsettrx() {
 	if ($("#flrig_ena").is(':checked') || cfg.profiles[active_cfg].hamlib_ena) {
 		console.log('Polling TRX '+trxpoll);
-		x=get_trx();
+		const x=get_trx();
 	}
 	trxpoll = setTimeout(() => {
 		getsettrx();
@@ -267,7 +267,7 @@ const isDeepEqual = (object1, object2) => {
 
 	if (objKeys1.length !== objKeys2.length) return false;
 
-	for (var key of objKeys1) {
+	for (const key of objKeys1) {
 		const value1 = object1[key];
 		const value2 = object2[key];
 
@@ -335,11 +335,11 @@ function updateUtcTime() {
 }
 
 async function getStations() {
-	let select = $('#wavelog_id');
+	const select = $('#wavelog_id');
 	select.empty();
 	select.prop('disabled', true);
 	try {
-		let x = await fetch($('#wavelog_url').val().trim() + '/api/station_info/' + $('#wavelog_key').val().trim(), {
+		const x = await fetch($('#wavelog_url').val().trim() + '/api/station_info/' + $('#wavelog_key').val().trim(), {
 			method: 'GET',
 			rejectUnauthorized: false,
 			headers: {
@@ -352,7 +352,7 @@ async function getStations() {
 			throw new Error(`HTTP error! Status: ${x.status}`);
 		}
 
-		let data = await x.json();
+		const data = await x.json();
 		fillDropdown(data);
 
 	} catch (error) {
@@ -362,13 +362,13 @@ async function getStations() {
 }
 
 function fillDropdown(data) {
-	let select = $('#wavelog_id');
+	const select = $('#wavelog_id');
 	select.empty();
 	select.prop('disabled', false);
 
 	data.forEach(function(station) {
-		let optionText = station.station_profile_name + " (" + station.station_callsign + ", ID: " + station.station_id + ")";
-		let optionValue = station.station_id;
+		const optionText = station.station_profile_name + " (" + station.station_callsign + ", ID: " + station.station_id + ")";
+		const optionValue = station.station_id;
 		select.append(new Option(optionText, optionValue));
 	});