Hi N7EKU,
I tested three different model cell phones, and the noise comes through my 909X with all three, but doesn't come through through using any other radios.
Taking GRUMPY2021's test into account, I'll go under the assumption I own a bad copy of the 909X.
I just re-tested the radio on all 4 bands. Cellphone interference "loud and proud" on LW, MW. Interference is noticeable, but much more reduced on SW and easily blends into the normal SW static (except I was looking for it), and the interference NOT noticeable on FM.
It looks like the 909X is most sensitive to the cellphone interference from it's internal ferrite AM/LW antenna.
This is really too bad, because my 909X's reception on MW is outstanding, except for the issue with the cellphone interference.
Thank you,