[time-nuts] 1900kHz radiolcation testing on east coast US?

Chuck Harris cfharris at erols.com
Sun Dec 7 20:41:20 EST 2014

Hi Tim,

Look for a switching power supply that is fairly new, and is
of the sort that doesn't need to be messed with to cover the full
120V to 240V range.

That sort of switcher is also known as a power factor correcting
switcher.  It has a PWM switched pre-regulator that takes the
unfiltered ripple straight from a full wave bridge rectifier, and
PWM's it so that it can charge the filter capacitor, without the
power line seeing anything but a resistive load.  It also controls
the inrush current.

PWM pre filters, because they quickly shift the pwm signal at a
120Hz rate, are capable of producing lots of broadband 120Hz
modulated garbage if their shields, or filters are compromised.

-Chuck Harris

Tim Shoppa wrote:
> Would any time-nuts know of radiolocation-type testing going on, on east
> coast of US, maybe around Maine? There is a very strong wideband signal on
> 1900-1920kHz, with a 120Hz substructure and a 4Hz rep-rate, likely megawatt
> power range.
> Sound sample (recorded with 2400Hz receiver bandwidth, although the whole
> signal is far far wider bandwidth) at
> http://www.trailing-edge.com/1910-intruder.wav
> Pics of the waveform at http://www.trailing-edge.com/1910-intruder-1.png and
> zoomed in at http://www.trailing-edge.com/1910-intruder-2.png
> Tim N3QE
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