Shouldn’t be a problem in your enclosed fixture?, although it would be sad to loose the lamp prematurely? 🤔

Over here, the low floor city busses in my city have blue lights in the front that are dimmed when driving but come on when stopped, the lights at the back are just normal white. I believe this is done to keep the drivers night vision.

I thought of this thread a few weeks ago, when it started getting lighter later in the morning. I was sitting at a stop sign behind two school busses, and both had the interior lights on while moving down the street and at the stop.

@Ash, yes usually they transfer the fixtures here as well, even if they aren’t used anymore. There is an OLD mercury  GE M400 at the Enterprise here (was an old gas station) that hasn’t worked in a few years, when the pole was replaced, they transferred it anyway.

@BT25, most of the ones here aren’t installed on a separate pole either, my next door neighbor used to have two HPS NEMA heads requested by a previous owner. When they stoped paying, the PC were removed. When a new house was built, they removed the one from the transformer pole to install an underground feed. The other fixture was on a separate pole, and remained for a few more years until the current owner had a steel garage built in that spot, so the power company removed it and the pole. I was at work when the work was performed, I wish I’d been home since maybe I could’ve gotten the fixture and arm, being they weren’t going to be used anymore.

@HomeBrewLamps, I’ve seen that here too actually. There was a GE M250R2 at a house that was demolished, but the fixture was never disconnected and still had power. Although the HPS lamp started cycling. I doubt they ever disconnected it, but I haven’t been by that way after dark lately.

Thank you for providing this invaluable resource, @Olav . 

The point was to use it not for measurement, but for calibration while still staying on DIY budget. For calibration the jitter is way less critical, the only thing it impacts is the time how long you need to compare the signals.
With any stand alone instrument you will always face a question whether it still works. With radio reception also carrying the timing standard you have that information: Either it is locked, so accurate, or ot is not locked and then you know that.
With GPS you know that - either it reads your position correctly (then it is clearly locked; assume you know where you are so are able to verify that), or not (so then it does not work at that moment).
Also with the analog TV: It either showed correct image, then it must have been locked, or it was not.

Of course, any radio based timing signal distribution does suffer from jitter, that why it could be using just for calibration of some more stable and cleaner generator. In that respect the GPS provides still the best quality signal, compare to other methods available for similar money.

I hope this don't increases the risk of an arctube explosion?

Interesting 🤔, maybe the environment they were made in wasn’t as pure as it was with European manufacturing?, and airborne particles stuck to the tube when still hot from moulding?
I haven’t seen this before?

The dirty is on the outside of the arctube.

I don’t have one now 😬, years ago me and my neighbour across the street, Mick, tried to out do each other each year 🤣, he eventually beat me though with a full decorated tree on top of his porch! 🥳
Over the years though each one of my outside decorations failed and decent ones were no longer available where we use to get them from!
It came to a head last year when my giant Christmas candle with moving flame effect half went out, I took it all down in January this year and promptly disconnected the entire feeds going to them all!

The 3 remaining working ones we now have up inside the house, I don’t bother with anything outside anymore sadly 🙁