Avoid channel update during channel scan

[ArthurDent75]

Hi,
my problem is that during DVB-T channel scan the tv server substitute (update) an alreay found channel with the new one.
Because of my poor english I'll make an example:
The scanning found the channel xxx at frequency, let's say, 175000.
Then it find the same channel at a new frequency 448000.
In this case it subsitute the channel xxx with the new frequency.
The problem is that, in my specific case, the signal is better in the first occurrence of the channel.

At the time I have to do a tricky thing stopping the scan and exporting the channel list in xml for every frequencies and then make a collage and re-import it again.
Actually I'm doing a more tricky thing: I put a trigger on the table dbo.TuningDetail which copy all the data while scanning in a new table without updating them. After that the messy thing is copy the data and to re-assign IDchannel and IDtuning.

There is a way to avoid it?
Simply choose to use or not use update?

Thanks,
Alessandro.