I note that there have been a some replies, but none seem to make much
attempt at answering your question.

THANK YOU IAN!! A thousand points for noting this.

RG6Q is used extensively in the UK cable TV industry as 'drop' cable -
ie from the taps in the street cabinet to the home. It is used to
provide a high degree of immunity from ingress of interfering signals -
especially those at the lower frequencies (in the reverse path part of
the spectrum - typically between 5 and 65MHz). RG6 is not a particularly
low-loss cable, and for long drop runs, RG11 is sometimes used.

As for the attenuation differences between RG6 and RG6Q, I've done a bit
of Googling, and I can't see anything which is immediately pointed out.
Even on this site
http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html
all it says is that "RG-6 and RG-6Q share nearly the exact same outer
dimensions and have similar flexibility. RG-6Q is slightly stiffer due
to the increased amount of inner shielding".

And another thousand points for answering the question--which was about the
cable's specs, NOT ABOUT ITS APPROPRIATENESS FOR A SPECIFIC APPLICATION.

I suspect that even if the diameter of the RG6Q dielectric is slightly
less (something which I've never really noticed) - requiring a slightly
thinner inner conductor in order to preserve the Zo - the increase of
attenuation won't be very much. However, I'm sure that a bit more
intensive Googling on RG6 physical and electrical specs will reveal the
true answer!
Ian

The question was how does RG6 compare to RG6Q, specifically whether or not
the reduced diameter of the dielectric effects its specifications.

Best to you.