HI John, I just saw this posting, so sorry for the delay. I have a two-digit B7971 clock that I built from a kit about 15 years ago. It runs directly off of the 110V mains, so there is no switching supply involved here - just a transformer, rectifier and some filter caps on the clock's power supply board.
The clock displays the hour for one second, then the minute for another second. Before the hour is shown again, the clock does a "flick-flack" routine for another second. It makes two clockwise "rotations" by sequentially lighting up each tube segment that is connected to the center of each tube. There is a very annoying a buzzing sound in sync with the flick-flack that I could hear on 40M and 80M. I have been lazy, and just put the clock in a room on the other side of the house from where the ham equipment is kept. I have also improved my grounding and antennas, so I no longer hear the clock. Maybe some day, I'll chase down the clock's noise, or just try a toroid on the clock's power cord (which is a long one - so I'm sure it acts as a decent antenna), but for now, I don't think the clock is as much of a problem as all of the cheap wall-wart supplies that power all of my wonderful electronic gear - my house's noise level is about S4. This stuff has all of the required stickers, but I think most of them mean absolutely nothing. I believe the manufacturers just stick them on without thorough testing, knowing that the FCC does not have the resources to do anything about it. Anyway, I have a lot of other noise to sniff out before diagnosing the clock. Good luck. 73, Jim On Thursday, August 15, 2019 at 10:27:25 PM UTC-6, johnk wrote: > > From time to time I come across discussions where radio restorers > [domestic and mil] want a low current valve-voltage (tube-voltage) power > supply. > > I often suggest that they look at the various Nixie supplies discussed > here. > > > > The usual response is along the lines that ANY “switching” or > not-linear-regulator supply will cause too much “noise” on the radio bands > involved. > > > > Are there any active ticketed amateur radio guys here who have had > first-hand experience of this topic and are willing to share their wisdom? > > > > John K > > Australia. > -- 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/01d55f1d-cec0-4104-9839-0dd599de7a6a%40googlegroups.com.
