Quisk patch for Hardrock-50 HF power reading with Hermes-Lite 2

pwr.patch

diff -u a/hermes/quisk_widgets.py b/hermes/quisk_widgets.py
--- a/hermes/quisk_widgets.py	2017-11-09 10:36:54.709441866 +0100
+++ b/hermes/quisk_widgets.py	2017-12-25 18:06:55.172739588 +0100
@@ -7,6 +7,12 @@
 
 import wx
 
+# 3v3 rail measured with voltmeter
+volt3v3 = 3.256
+
+# voltage for 50W measurement
+pwr_ref = 2.15
+
 class BottomWidgets:	# Add extra widgets to the bottom of the screen
   def __init__(self, app, hardware, conf, frame, gbs, vertBox):
     self.config = conf
@@ -85,11 +91,19 @@
     current = " Ampl %4d ma" % (1000*current)
     self.text_pa_current.SetLabel(current)
     fwd = self.hardware.hermes_fwd_power
+    fwd = 50.0 * (volt3v3 * (fwd/4096.0) / pwr_ref)**2
     fwd = " %3.1f watts" % float(fwd)
     self.text_fwd_power.SetLabel(fwd)
     rev = self.hardware.hermes_rev_power
-    swr = 1.2
-    swr = " SWR %3.1f" % swr
+    if self.hardware.hermes_fwd_power > 0:
+        gamma = float(self.hardware.hermes_rev_power) / float(self.hardware.hermes_fwd_power)
+        if gamma < 1.0:
+            swr = (1.0 + gamma)/(1.0 - gamma)
+            swr = " SWR %3.1f" % swr
+        else:
+            swr = ""
+    else:
+        swr = ""
     self.text_swr.SetLabel(swr)
   def OnTextDataMenu(self, event):
     btn = event.GetEventObject()