Improving OTA reception

[SoupMama]

I just moved and recently set up my Voom box and Winegard antennae. No matter where I put it, I can't get perfect reception on all the channels I want.
I've got it in the best possible location, but I still struggle to receive NBC. When tuning in setup mode, the strength jumps back and forth between 94 and 55.

I tried putting this in the line
Winegard PS-9370 TV Antenna Power Supply Pre Amp Power Inserter Injector In-Line 18V 18 Volt ChromStar 110 VAC for All Off-Air Aerial Signal Boosters / Pre-Amplifiers, Part # PS9370: Oak Entertainment Centers and Home Office Furniture, TV Antennas, A
and removed the diplexor, which resulted in little-to-no improvement.

Anyone have any suggestions on how to improve my signal strength? Should I move the auxiliary power supply closer to the antenna or closer to the TV? Will that help?

 

[dodge]

Sounds like you have a multipath problem with the signal jumping from 55-95, what is your zip code???

 

[oldvoom]

I've noticed with some line amps that they actually limit the output to 25db or whatever, depending on their configuration.

I use an RCA big ugly in the attic, and I know it is putting out well over 40db, and possibly 60+, based on some experiments and calculation, so the two line amps I had played with actually reduce the signal.

I don't know what winegard you have, but maybe you are inadvertently limiting the signal in some cases? Although the multipath answer sounds like it should be followed up first.

 

[SoupMama]

My zip code is 27587. I live exactly 2 miles due west of wear Google maps places the marker for 27587. It is flat, but there are a lot of tall trees.

I have the Winegard Amplified Sensar that came with Voom. I can get all of the channels predicted by Antennaeweb with signal strengths >95, except Fox and NBC. I have spent several hours on a ladder, trying to position the antennae, but I have yet to find an arrangement that allows me to get BOTH channels to come in. Sometimes, just a shift of 1 degree causes one channel to sudden come in strong, and the other to fade. Sometimes, my position choice causes me to lose PBS 4.

I've tried mounting on the south side of the house and on the east side. I'd prefer not to mount it on the west side, as this is the front of the house.

Recently, I purchased the Radio Shack 15-1634 to see if an omindirectional antenna would help. That resulted in no improvement at all.
RadioShack.com - Home Entertainment: Accessories: Antennas: Outdoor: Low-Profile Omnidirectional Amplified TV Antenna

I'm at my wit's end. Is it my wiring? Perhaps I just need an antenna optimized for my situation. Can anyone recommend the right antenna for me?