Weird reception in Harris County

[crepehanger]

At least at my house in southern Harris County. I'm about 20 air miles from Cusseta and 12 to Buena Vista Road. I wasn't happy with how my antenna (CM 4221) was mounted on my chimney and went up to remedy the situation. While I was at it, I changed from a 5 ft mast to 10ft. Below is what I am receiving.

Before

WRBL--80-85%
WTVM--70%
WLTZ--93%
WXTX--100%
WJSP--75-80% (BTW, JSP is apparently off-air the last few days)

After

WRBL--70%, with lots of dropouts
WTVM--80%
WLTZ--94%
WXTX--99%

Anybody have any possible reason why the change in WRBL? I would have thought a higher antenna elevation would have helped the signal strength. I'm even wondering if a 4228 would be more appropriate since I have a LOT of trees. I do not have a amp on the antenna. I tried a CM preamp before, and it made no difference in reception, so I returned it.

[kenny]

crepehanger,
I also live in Harris County in roughly the same area. I used indoor Terk antennas and they work fine. I usually get 100% signal strength from WRBL. I was considering getting and outdoor antenna to boost my WXTX and WTVM signals to be constantly over 85%. I would be intrested to know the cause of this problem before make any changes.