2008-05-02, 03:59 PM
There is some leeway when tuning QAM. There is a swing of a few khz (I can't remember how much) so you could tune the same channel at 507000 and also at 507250. This may account for the differences you are seeing. GBPVR may be tuning the correct frequencies and some of the frequencies tuned by OA may be just close enough to find the channel.