channel tuning problem

[gand]

I'm having a problem whereby *occasionally* a channel will not tune. It is not any channel in particular, and there does not seem to be any pattern. But when I'm flicking channels I will eventually get to one that gives 'No Signal'. If I leave it sitting on 'No Signal' it will normally tune eventually (after a couple of minutes).

Have tried offsetting (reduce freq by 167) the frequencies in my frq file, as I noticed others had fixed tuning problems by doing this, but still the same.

Have checked the registry to make sure the frequencies are not being overridden there (noticed some people also had this problem), but frequencies are not set there. The frequencies are definitely being read from my frq file - just strange that the channel will tune most of the time but every now and then will not (very annoying )

I'm using a Compro Videomate DVB-T200 card - have tried updating to the latest drivers but still no luck.

Have tried all sorts of combinations of video decoders / renderers but no luck.
Have tried with v6 beta but still exactly the same issue.
Have also tried tweaking a couple of the sage.properties settings (e.g. always_autotune) but still no success.

Could it be that sage is timing out when trying to tune - is there a setting that can be changed to adjust this timeout?

Any ideas would be very much appreciated - I've just ordered an MVP and would like to get this sorted before sage moves into my living room!

Many thanks in advance

Gand

(Windows XP SP2, AMD Sempron 3000+ (1.8GHz), 512MB DDR, Overlay Video Renderer, SageTV MPEG Video Decoder)