From 63b9e98b07ce71efadd7c86723c2ce2b8cf85b14 Mon Sep 17 00:00:00 2001
From: techniX <sergei.mozhaisky@gmail.com>
Date: Sun, 8 Dec 2019 17:10:46 +0200
Subject: [PATCH] allow empty frequency (turn off)

---
 helpers.lua     | 3 +++
 transmitter.lua | 7 ++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/helpers.lua b/helpers.lua
index 9c1ff72..d00f430 100644
--- a/helpers.lua
+++ b/helpers.lua
@@ -1,4 +1,7 @@
 function ham_radio.validate_frequency(frequency)
+  if frequency == "" then
+    return true -- empty frequency is allowed to disable transmitter/receiver
+  end
   local transmission_is_allowed = true
   local num_freq = tonumber(frequency)
   local freq = tostring(num_freq)
diff --git a/transmitter.lua b/transmitter.lua
index 8125878..c953930 100644
--- a/transmitter.lua
+++ b/transmitter.lua
@@ -1,7 +1,12 @@
 
 ham_radio.transmitter_update_infotext = function(meta)
-  local infotext = {'Frequency: ', meta:get_string("frequency")}
+  local frequency = meta:get_string("frequency")
   local broadcast_message = meta:get_string("broadcast_message")
+  if frequency == "" then
+    frequency = "--"
+    broadcast_message = ""
+  end
+  local infotext = {'Frequency: ', frequency}
   if broadcast_message ~= "" then
     table.insert(infotext, '\nBroadcast: "')
     table.insert(infotext, broadcast_message)