I'd still have to see where connectors and grounding and etc. is going on inside there, but 99.5% sure it's absolutely, positively no issue whatsoever.
Assuming that means FCC Part 15 compliance. Or maybe even Part 18, even easier?
Ok interesting, thanks for the reply But you're speaking about signal speed, though? my signal speed is very very low, it's below 10kHz. So my only concern is more regarding the signal edges, hence looking at the rise/fall time.
Nonono-- your clock or bit rate might be 10kHz, the
transition rate is on the order of 5ns from the MCU (as low as fractional ns for higher speed MCUs, up to maybe 20-30ns for old or slower ones, or slew-rate-limited settings), and probably a fall time of 10ns from the BJT. That means harmonics all the way up to corresponding frequency scales, i.e. 50MHz. Maybe not much, at the low rep rate, but you're also talking an electrically-short antenna so it has its own gain proportional to frequency characteristic that balances it out, and you get blips from it.
The kicker is:
1. Trace in PCB is poorly coupled to free space -- this is already enough to pass, e.g. on-board UART signals at 3.3/5V rarely if ever cause trouble;
2. Excessive source termination resistor means the leading edge is attenuated significantly to begin with (i.e. about 20dB);
3. Enclosure, assuming it's at least moderately well grounded to the board, and connectors aren't spreading around common-mode noise somehow coupled to the trace in question (but, coupling has been said to be very low, so that seems impossible), can easily knock that down another, say, anything from 20dB to over 100.
"Well grounded", at these edge rates, might be as simple as a single mounting screw; a great connection isn't really necessary. Well, assuming the enclosure and board aren't massive or anything, but like palm sized.
More likely all the other connectors emit exponentially more noise, but you asked specifically with respect to one trace, and, it's one of the relatively rare cases, an EMC problem sufficiently well specified and constrained, that a more or less direct answer can be given.
Tim