I was trying to follow a friend's flight from SFO (San Francisco) to LAS (Las Vegas) today using LiveATC, and I noticed that only three of maybe 30 Oakland Center sectors appear to be on LiveATC at present. I was using this map of Oakland Center frequencies to make that statement:http://www.freqofnature.com/aviation/zoa/
I lost my friend's flight as they were passed into one of the missing Oakland Center sectors, then regained them on LAS Approach.
Is it generally the case on LiveATC that only a fraction of the regional center frequencies are being covered? This is a function of the fact that to cover a frequency there needs to be some generous end user out there who tunes the frequency 24x7 and then feeds it to LiveATC's servers?
Looking forward, how soon would the site likely have coverage of most of the Oakland Center frequencies?
Since the feeds are generally dealing with scanners sitting on the ground, the scanner in question has to have line of sight with the facility or repeater in the area. In this case, I can easily say that the missing feed was probably between 132.95, and ZLA's HI sector in that area, which would be 124.62. Unless someone has a feed set up in or around the area of that repeater for those frequencies, you probably won't hear them.
CAVEAT: You will just about always have line of sight with the pilot, unless they are completely out of your scanner's range, and I don't know if you could hear that frequency if you were near the facility (ZOA Center), as it would be the source. I doubt it, though.