On 4/4/2010 10:18 AM, Frank McElrath wrote:
Rather than split and amplify an HD antenna in my attic, I decided I'll just
get an additional one with a dedicated lead.

Any idea how much horizontal separation I would need for an anntena of this
type:

http://www.amazon.com/RCA-ANT751-Out.../dp/B0024R4B5C


Sounds as if you are trying to feed 2 separate devices. If so, the potential
problem would be mutual reflections of the received signals between the 2
antennas. That would set up multi-path ("ghost" problems in the days of analog
signals) reception in both antennas. The end result would be degraded signal
strength for at least some of the stations received.
The information to accurately answer the question (and not available) is the
reception pattern of both antennas. If both are highly directional, you are
likely to have less problems. If either or both of them are multi-directional
or omni-directional, you may need more separation to avoid problems.

If you have the room in your attic, I would try to align both antennas parallel
to each other, or vertical to each other, rather than 1 in front of the other.
Also, the signal loss through an additional 10-20 feet of coax is so minimal
that in general, I would try to space the 2 antennas as far apart from each
other as room allowed.