I'm trying to figure out if I need a preamp. Here's my tvfool report:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d03fbd917172971

I'm on the first floor of a three story house. The RG cable run is about 40ft from my samsung stb to the roof antenna (aimed North West). I don't know the exact brand of antenna but it looks something like this. (http://www.amazon.com/Channel-Master-3018-Mid-range-outdoor/dp/B000SAKJ4Y)

Some channels are weak and some channels drop in and out after sunset. Trying to figure out what to do.

It does not appear that you need a preamp. You are about 5 miles away from most of the transmitters. You are more likely to encounter the opposite problem, signal overload. In your area, a preamp will only make things worse.

Using an AM radio tuned to a weak radio station, I would also check for nearby sources of interference, like a street light or other ballasted lamp that turns on after sunset that could be spewing interference across the bands. In a very urban environment this could be very difficult. Are the VHF stations like WABC the ones affected?

At your distance from the transmitters, any amplification will certainly make things worse.

I would;
1. Try an FM trap.
2. Check all connections.
3. Confirm antenna aim.
4. If none of the above helps; replace the antenna with either an Antennacraft HBU-22, or Winegard HD7694P.

Samsung tuners are a bit sensitive to overload, but I doubt this would be an issue 5 miles from the transmitters.

Using an AM radio tuned to a weak radio station, I would also check for nearby sources of interference, like a street light or other ballasted lamp that turns on after sunset that could be spewing interference across the bands. In a very urban environment this could be very difficult. Are the VHF stations like WABC the ones affected?

I was afraid of that. VHF and UHF seem to be affected (CBS, NBC, ABC, PBS...). Some worse than others.

At your distance from the transmitters, any amplification will certainly make things worse.

I would;
1. Try an FM trap.
2. Check all connections.
3. Confirm antenna aim.
4. If none of the above helps; replace the antenna with either an Antennacraft HBU-22, or Winegard HD7694P.

Samsung tuners are a bit sensitive to overload, but I doubt this would be an issue 5 miles from the transmitters.

I will try an FM trap and check the connections. There aren't any really tall buildings in the way except for a public school which is about a block and a half away (but also right in the path of the antenna). All other houses are about the same level height and cause no obstruction.

If I have to, I don't mind replacing the antenna with something more suitable.

Make sure you have the antenna pointed in the right direction.
Do not buy an amp, you'll overload the tuner and signal quality will get worse, not better.
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