RCA drd430rg and over the air antenna

[mort]

Hello out there:

I have an older tv and can't afford to upgrade to HD yet.Directv's digital
signal is still pretty good coming thru my analog set.

When i bought my house i had an over-the-air antenna installed above the
roofline on my house.I would like to use this antenna thru my directv
reciever because all the local stations in my area are broadcasting in
digital.

If i use a multiswitch/diplexer setup would i be able to pull in my
over-the-air channels with the same quality as the directv digital signal?

TIA