FYI, KTXA has been going through some changes. Their original RF digital channel was 18, which later changed to channel 19 on June 12th. Then on August 4th, they switched back to channel 18 so that KTVT could switch to channel 19. As of right now, KTXA is on channel 18 with only 220 kW of power.
KTXA is planning on moving to channel 29. On November 19th, KTXA was granted a construction permit for a new facility on channel 29. When this new transmitter is finished, they will flash-cut over to channel 29 with 1000 kW of power. I'm not sure when they will be ready for switch, but it's probably coming soon.
Just keep in mind that your reception of KTXA is probably going to change soon. You may also need to do a re-scan of your channels to make your receiver notice the change.
More generally speaking, there may be a few different explanations for your reception difficulties. The most plausible explanations are:
- Amp overload
- Interference
- Multipath
If the amp built into your antenna is getting too much signal, it can overload (kind of like distortion), which can make your receiver lose signal lock. Without seeing a tvfool analysis for your exact location, I'm not sure how strong the signals are where you are, so I'm not sure how likely this is to happen. It would help if you could post this information so that we can see what kind of signal strengths you're dealing with.
You also mention that the problem is intermittent. This could be either interference (microwave oven? vacuum cleaner? power lines? ham radio operators? etc.) or multipath (people walking in front of the antenna? airplanes flying by? trees blowing in the wind? etc.). If you notice any correlation between your picture dropouts and these other things happening around your house, you might be able to identify the dominant cause of the signal breakups.
If you suspect that multipath is your problem, then moving the antenna higher (like the attic or roof) can help a lot. In most buildings, the first floor is usually surrounded with more "RF clutter" (people, walls, cars, fences, trees, neighbors' houses, etc.) that the TV signal must pass through before it reaches your antenna. Antennas placed in the attic or on the roof usually get above a lot of this "clutter" and therefore have a cleaner signal to work with.
Best regards,
Andy