[time-nuts] Hydrogen maser frequency jumps

Tom Van Baak tvb at LeapSecond.com
Sat Dec 5 11:06:40 EST 2015


Jim,

Check IF level and H2 pressure. Also see if OCXO tuning is near a rail. Go back through the past month and look at trends on all the parameters. You are logging all channel data, I hope.

Also check your microwave ovens: http://arxiv.org/pdf/1504.02165v1.pdf  ;-)

Less technical links:
http://www.nature.com/news/microwave-oven-blamed-for-radio-telescope-signals-1.17510
http://www.skyandtelescope.com/astronomy-news/microwave-ovens-spark-radio-signals-peryton-05122015/
http://phenomena.nationalgeographic.com/2015/04/10/rogue-microwave-ovens-are-the-culprits-behind-mysterious-radio-signals/

/tvb


> Has anyone here who is familiar with hydrogen masers ever experienced a
> sudden jump in phase of the 5MHz output?
> 
> We have found they occur semi-regularly (few times a week) and are trying
> to find a culprit.
> 
> The weird thing is that the jump is ~0.7ns and that 1/0.7E-9 is close-ish
> to 1420.4MHz which is the hydrogen line. Too much of a coincidence for me.
> 
> These seem to be appearing at three different locations with the same model
> of maser at each location. I won't mention the model publicly.
> 
> We're still investigating various potential causes (e.g. power spikes,
> cables being moved), but this 0.7ns figure is niggling me.
> 
> Has anyone here ever seen such a thing before?
> 
> 
> Jim



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