I have an HR21 700. I recieve both HD and SD channels perfectly except for the last week or so the HD Fox Sports Channel 687 pixelates and stalls about every few minutes. Sometimes every 20 seconds. This only occurs on this channel. I have reset my receiver several times and my satellite readings are all very high and all other stations are fine including the SD channel 687. Is this my equipment problem or is it originating with the broadcast station?