I am noticing no difference here in Merced County. 153.770 is the all county dispatch channel.
I also get the Modesto County Cmd 5 channel here in Merced Co on my hight level antenna system as I always have. This is a Modesto City channel that goes to the Modesto dispatchers rather than the Stan Co Fire dispatchers from what I can tell. Modesto incidents also use the Modesto tac channels. I would presume that this system allows Modesto to expand as a need might require to the county channels. We have that ability in Merced ****y should the need ever arise.
You will see the Turlock channel use as tac in areas other than Turlock, as it is also used as a bridged channel to the Turlock Fire 800 system. I do not know how the licensing is on that channel - if it' by agreement alone or is Stan Co added it to their compliment of licenses. With agreements in place, neighboring agencies can use their neighbor's frequency, but that is not the norm.
Reflection on low signal - maybe someone is pressing the wrong transmitter button? Or some other technical issue? Maybe they are narrowbanding, where levels are sometimes much more noticeable if misconfigured.