Missing radio time signal from Anthorn?

I have 4 Anthorn clocks - woops, one needs a new battery. That one restored saying the same time as the others. That would seem to imply Anthorn is working.

It's never been quite as good for me as it was when in Rugby.

I can see an interference spike at 60 kHz in my lightenig detector signals.

Lightning detector which model is that Dave?

Just curious..

Do you contribute to lightning.org perchance?.

En el artículo , Dave Liquorice escribió:

I've just realised I have an open-box (barebones) PC undergoing testing on a bench nearby, about 1.5m from the clock. The RF from that is probably swamping it (and a lot else!) and the outage corresponds roughly to when I switched on the PC.

It's undergoing data recovery at the mo so I can't turn it off just yet.

That is likely. When the signal was from Rugby a clock was OK next to the case; now it's on the other side of the desk and the light on it isn't as good. I move the case, but it won't go under a shelf.

He said lightening detector. I.e. his bathroom scales.

Yes i suspect the clock in question probably has died or maybe if its an all singing and dancing type its software is scrambled. Brian

Not enoughcopper in the ground probably! Some use a german one don't they? Brian

I always thought lightening was pretty broad band.

Brian

Well, not convinced, can't you move the clock instead? Brian

A Blitzortung system Blue. A co-operative time of arrival system.

It is. The Blitzortung reciever goes from a few kHz up to aboout 150 kHz but most of the energy is below 25 kHz.

A desktop PC doesn't even need to be opened for its operation to interfere with a radio synced clock, just close by (within a few yards).

The emc screening is mere 'tokenism' in most cases, at best, maybe reducing emissions by a mere 10dB or so. Effective containment of RF hash generated by digital kit to within the confines of its metal box is a lot harder than it looks to the public at large. Having an al fresco PC operating nearby will almost certainly account for the lack of reception of the time standard transmissions.

Refitting the covers will mitigate the problem but won't necessarily guarantee restoration of the status quo. You may have to shut the machine off completely before that can happen. If you need to keep the job running for many more hours, you'll have to temporarily relocate the radio clock to another room for a short while (half an hour or so?) to allow it to sync back up.

As you ought to know, Brian, it's not a matter of a low impedance grounding connection, it's a matter of *screening* which can range from a simple sealed metal box for a battery powered interference source to a more sophisticated ventilated "box within a box" with pass-through capacitor feeds for power, input and output signals supplemented with high quality filtering components incorporated either side of the pass- through capacitor feed connections.

Is that why the radio controlled clocks at my work won't reset during the day, but recover through the night (when the PCs are off)?

And there was me telling the staff it was because the radio signals have a long way to travel and propagate better during hours of darkness.

====snip====

Yes! That's it exactly! :-)

That applies to medium wave broadcasts, less so for the long wave broadcasts and virtually not at all for the VLF wavelength used by Anthorn (72KHz? - I know it's close to the 60KHz that (is/was?) used by Rugby MSF) which was chosen for its more consistent groundwave propagation characteristic.

It's 60 kHz. Technically, it's LF (not VLF), as VLF is only below 30kHz.

En el artículo , Johnny B Good escribió:

There /are/ no covers. It's a bare board on the bench with five hard discs attached :)

It's the one with a zfs array that I recently posted about in uk.comp.homebuilt.

oh, I can wait. I've got the PC clock which is NTP sync'd.

I just hadn't connected the loss of radio clock sync with setting up the barebones PC.