add multicapture.py to capture other satelltes as well as NOAA,

such as 2way ham radio sats like OSCAR-50

.gitignore

@@ -1 +1,2 @@
 *.pyc
+*~

multicapture.py

@@ -0,0 +1,86 @@
+import time
+import pypredict
+import subprocess
+
+def decode(fname):
+    cmdline = ['/root/atpdec-1.7/atpdec',fname+'.wav']
+    subprocess.call(cmdline)
+
+satellites = [\
+	{'name': 'NOAA-18',\
+	'freq': 137912500,\
+	'postProcess': decode },\
+	{'name': 'NOAA-19',\
+ 	'freq': 137100000,\
+	'postProcess': decode },\
+	{'name': 'NOAA-15',\
+	'freq': 137620000,\
+	'postProcess': decode },\
+	{'name': 'OSCAR-50',\
+	 'freq': 436795000 },\
+        {'name': 'ISS',\
+         'freq': 145800000 }\
+]
+	
+sample = '44100'
+wavrate='11025'
+
+def runForDuration(cmdline, duration):
+    try:
+        child = subprocess.Popen(cmdline)
+        time.sleep(duration)
+        child.terminate()
+    except OSError as e:
+        print "OS Error during command: "+" ".join(cmdline)
+        print "OS Error: "+e.strerror
+
+def recordFM(freq, fname, duration):
+    # still experimenting with options - unsure as to best settings
+    cmdline = ['rtl_fm',\
+               '-f',str(freq),\
+               '-s',sample,\
+               '-g','43',\
+               '-F','9',\
+               '-A','fast',\
+               '-E','dc',\
+               fname+'.raw']
+    runForDuration(cmdline, duration)
+
+def transcode(fname):
+    cmdline = ['sox','-t','raw','-r',sample,'-es','-b','16','-c','1','-V1',fname+'.raw',fname+'.wav','rate',wavrate]
+    subprocess.call(cmdline)
+
+
+def recordWAV(freq,fname,duration):
+    recordFM(freq,fname,duration)
+    transcode(fname)
+
+def spectrum(fname,duration):
+    cmdline = ['rtl_power','-f','137000000:138000000:1000','-i','1m','-g','40',fname+'.csv']
+    runForDuration(cmdline,duration)
+
+def findNextPass():
+    predictions = [pypredict.aoslos(s['name']) for s in satellites]
+    aoses = [p[0] for p in predictions]
+    nextIndex = aoses.index(min(aoses))
+    return (satellites[nextIndex],\
+            predictions[nextIndex]) 
+
+while True:
+    (sat, (aosTime, losTime)) = findNextPass()
+    satName = sat['name']
+    freq = sat['freq']
+    now = time.time()
+    towait = aosTime-now
+    if towait>0:
+        print "waiting "+str(towait)+" seconds for "+satName
+        time.sleep(towait)
+    # dir= sat name and filename = start time 
+    fname='./'+satName+'/'+str(aosTime)
+    print "beginning pass "+fname+" predicted end "+str(losTime)
+    recordWAV(freq,fname,losTime-aosTime)
+    if postProcess in sat:
+        sat['postProcess'](fname) # analyze, make pictures, graphs, etc.
+    print "finished pass "+fname+" at "+str(time.time())
+    time.sleep(60.0)
+