Sniffing around with E- and H-field probes, the largest contributor I can find are fast edges going over SPI lines on ribbon cable between multi-tube carrier PCB... quite obvious up to and beyond 1.5 GHz. I can see the digit fade activity on the spectrum analyzer... Noise for the first half second or so while cross fading between digits. Relative quiet the second half second. This with the probe right on the cable. All the noise significantly reduced just a small distance from the ribbon cable. Not much coming from the pcb proper with 4 layers including power and ground.
I'll add a small value series resistor where high rep rate signals launch out onto cabling... slow the edges for clock and data lines. All of this while PWM dimming the display tubes at 15 kHz or so. Lots of HV switching that doesn't seem to be a large contributor. By *FAR*, the strongest signal I noticed in my shop was 10 MHz from a BNC cable running between my 10 MHz reference and a counter input. Hmmm... All the clocks, computers and assorted electronic gadgets may be part of the S7 noise floor I observe on 40M... will have to see what happens with the clocks and computers turned off! Bob -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/4f22b847-8f0e-46fc-bffc-5ca1d53b3d18%40googlegroups.com.
