I am no expert on TV and FM antennas. I do have some experience with
signal splitters and combiners.
It just seems logical that you will get the best antenna performance by
mounting them "back to back" and as far apart as you can without making a
BigJob of it.
As I understand the system connections you are using, both antennas
are
being fed from one amplifier thru a signal splitter. That will be as
though you have one antenna thats physically two antennas fed in parallel
with a phase lead or lag dependent on the lengths of their coax. If
both
antennas are well matched, the receiver's signal would drop 3 dB when the
second antenna is connected thru that "Signal Splitter", even if the
radiation pattern wasnt effected by that second antenna.

I think you have a very interesting project here. I also think you
will
be lucky to solve the "sometimes weak signal" problem using the
components
you now have.

How long is the coax and what kind is it?

Jerry

We will see what happens, I'll be sure to post the results. I am
still debating whether I need a better combiner or if they are pretty
universal for quality.

The coax from both antennas to the combiner is 6 ft RG-6, with the
combiner attached to the preamp with a coupler. Then from the preamp
to the 4-way splitter is about 15 ft of RG-6 QS + 20 ft RG-6. From
the 4-way splitter to each device is about 15-20 ft RG-6.

--
Chris

Hi Chris

I'm surprised that the amplifier is needed. But, you have determined that
it does improve reception so I have nothing to add to what you have done.
I do submit to you that the high quality splitter/combiner isnt likely to
provide you with any improvement in TV reception.
When you connect two seperate antennas to one output terminal, like with a
splitter, you then have One Antenna that has two feed points. Mount the
two antennas "back to back", and dont spend too much money on high quality
splitters.

Good luck
Jerry