Problematic channel in San Diego

[mchen1]

I've put up an OTA antenna, and I get all the channels I want EXCEPT for NBC. And it boggles me why I'm not getting NBC given my TVFool report and the reception I'm getting on other channels. Would you be able to help?

TVFool Report (20 ft): http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dd243e18cf07932
TVFool Report (1 ft): http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dd243808b607c49
Antenna: RCA ANT751
Mount: Outdoor Roof Mount, ~ 20-feet above ground level.
Direction: Started at 137* (magnetic, using compass), adjusted for best reception on problematic channel.
Wiring: 25-foot Coax straight down to a +15dB pre-amp, then into my house wiring, where it is split to a couple of different TVs. The splitter introduces a 3.5dB drop into the TV I am using to detect signal strength.
Problematic Channel: 39.1 (NBC), 22 miles away

Questions:
1) An important channel is PBS (15.1), and it looks like this is broadcasting from almost the exact same location as NBC (same direction and distance)! I get PBS loud and clear, with "78%" signal on my TV, whereas I'm getting 0-30% for NBC. In rainy weather, PBS stays clear, and NBC drops completely. Is this because both of these channels are "2Edge", and the paths are for some reason wildly different between the two?

2) Changing the antenna mounting height down to 1' gives me a higher NM (dB) value for NBC (and all other channels actually) on the TV Fool report (see above links). Does this really mean that if I mount on the ground I will get better reception? I haven't tried this, mainly because it took a lot to get the antenna up on my roof, and I don't want to fiddle around with it if I don't have to.

Thanks!

[ADTech]

The solution is as simple as it it is hard. You need to move the antenna and try again, it's in a "dead spot" for that station.

Making small changes in the simulator should be for entertainment purposes only. The underlying terrain and elevation data is of too coarse a resolution for the results to be meaningful.

[StephanieS]

Yes, play with location. Short of that, the ANT751 may not be enough antenna to work in 2-edge conditions coupled with KSND's 20 db strength. If I were installing here, my first attempt would be with something more robust such as an Antennacraft HBU33 orientated to magnetic heading 145 and see what my results yield.

Generally, I find the ANT751 performs wonderfully in line of sight conditions. Once you start trending weaker (25db) and lower coupled with terrain obstructions (1 or 2-edge) often a more powerful antenna is required.

I consider it excellent it is giving you KPBS RF 30 reliably. Remember though, this report does state KSND's signal is nearly 2 db weaker. You may be seeing the "bleeding edge" of how much the ANT751 can work with in this situation with KPBS on one side and KSND on the other.

Cheers.