TV Signal provider option in setup

[SunnyR]

Hi, Need some help!

Background - for the last 3+ years (or more, can't remember)
Use WMC in Windows 7, all updated.
Hooked to an LG TV as our screen.
Use HD HomeRun dual Tuner.
I'm in the San Francisco Area.
Our antenna on our roof has direct sightline to Sutro Tower.

Problem -
in the last week, we suddenly stop getting ABC (ABC7, KGO) - only 1 signal bar out of 6. Used to be 5 or 6 bars.
I thought it was the severe rainstorm we were getting. But the storm is over, and still 1 out of 6 bars.

Signals for all other channels that I usually watch are not affected. (E.g. PBS-KQED, CBS5, NBC11, and others.)

My various tests -
1. Our antenna direction has not been affected by the storm.

2. I use the LG TV itself, thus bypassing the computer, WMC, and the HDHomerun tuner. Surprisingly, the TV is getting ABC7 just fine!! So this means it's not my antenna nor my my antenna direction, nor the cable coming into the house.

3. I rebooted both our computer, and the HDHomerun tuner. But this did not solve the problem.

4. This next is the ODD & INTERESTING discovery.
I did a WMC setup all over again.
In the step "TV Signal provider", WMC gave me 2 choices (after it took several minutes to scan whatever it needs to scan)
a. "Oakland OTA Antenna"
b. "San Fran-Oak-SJ OTA Antenna"

In the past rare occasions when I had to redo setup, I believe I always chose b., since it covers all 3 major cities.
(Frankly, I really don't know what "TV Signal Provider" means. I am thinking may be it means transmission tower. But I only know of Sutro Tower in SF, which is where my antenna is pointing to. So why are there two "signal provider" "antenna"??)

This time, I chose a. "Oakland OTA Antenna" just to see what happens. Then WMC scans for channels, and lo and behold,
ABC7 is ON (6 out of 6 bars)!
But now, FOX (=Channel 2 = KTVU) is OUT (1 out of 6 bars)!

I redid the setup, and chose b. "San Fran-Oak-SJ OTA Antenna".
ABC7 is back down to 1 out of 6 bars. (My original problem.)
FOX (KTVU) is back up to 6 out of 6 bars .

All other "major" channels come through with good signals whether I choose "Signal Provider" a. or b.

Can anyone tell me what this means, why it's happening, and most importantly how to fix this. Obviously I cannot choose both a. and b. for my " "TV Signal provider" in the setup. And in the past, ABC7 and FOX (and other channels) come through just fine using"TV Signal Provider" choice b.

Additional (may be important?) NOTE -
During setup, in an earlier step called "Downloading TV setup data", I got
"Download failure - new TV setup data cannot be downloaded. The existing data, if available, will be used as you continue through TV signal setup."
And since my WMC has been setup from before, I can continue with subsequent steps, including the step where it scans and has me choose the "TV signal Provider".

[SunnyR]

In case anyone is curious what happens to this issue, it got solved.
See post #7 in this thread.
http://www.thegreenbutton.tv/forums/vie ... =5&t=10583