"szilagyic" wrote in message
ps.com...
On Jul 23, 10:42 am, "Smarty" wrote:
Since both antennas cover UHF, point in opposite directions, and are
spaced
within a fraction of a wavelength at UHF frequencies and below, it is
extremely likely that the phase cancellations of the two antennas causes
the
drop in signal strength when mixed in a combiner. The solutions are far
as I
can tell would be to bring both feed lines (coax lines) down to the
receiver
and switch when you need one or the other, or to filter out UHF content
from
the log periodic with a step low pass filter, or separate the 2 antennas
more, since you appear to be creating a phased array even though you
never
intended to by the way you are configuring them. Phased arrays
deliberately
add and subtract RF energy to gain directivity at the expense of
attenuation
in other directions.

Smarty




Thanks for the quick reply. Right now the best alternative is the
spacing as I only have one downfeed that uses a preamp. What would be
the minimum distance between the two antennas that I should use for
UHF considering VHF doesn't appear to be a problem, or is
it better to stack these instead, and if so what would be the minimum
distance that should be used? Or, would a metal barrier between the
two fix this issue with spacing??

I really appreciate the help.
--
Chris


Hi Chris

Is there a reason for not mounting the two antennas "back to back"?
Is there an amplifier at one antenna *before* the combiner? If so, why?

Jerry