Attached is a plot of line frequency measurements made by the FTM-III card in a
Truetime XL-DC. The FTM-III is meant for measuring line frequency in
generating stations, etc. It has a 0.001 Hz resolution. This plot shows a 3
hour window of data, histogram of the data, and
Interesting. Thanks.
I plotted your data next to mine.
http://users.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz-2019-June.png
There are actually 2 lines there. At this scale, they are on top of eachother.
My samples are roughly every 10 seconds. So there should be a 6 to 1 ratio.
If you
We have used line frequency counting for time keeping in the past it works
very well in the USA - EXCEPT in locations with lots of dimmers - theaters in
particular chop the AC waveform creating lots of noise and can make the
internal timer run fast. I think at one location we had 5 volts of
There are numerous devices out there that do non-contact detection of AC
voltage in wiring. The wire just has to be live and not connected to a load.
Fluke sells a nice one, but I like the GVD-505A from GB instruments because it
had a pot to adjust the sensitivity. It has a power switch on
It gets time from GPS and frequency from the power line at my house. I
suspect a certain amount of frequency wobble due to inductive loads
somewhere upstream of my home.
On Wed, Jul 3, 2019 at 8:01 PM jimlux wrote:
> On 7/3/19 3:20 PM, Jeremy Nichols wrote:
> > The station at Santa Rosa,
In order to add Truetime XL-DC (and XLi support) to Lady Heather, I bought an
XL-DC that happened to have the FTM-III module in it. This module is designed
to measure power line frequency for generating stations, etc, It works well,
but the minimum integration time is one second. You can
On 7/3/19 3:20 PM, Jeremy Nichols wrote:
The station at Santa Rosa, California (#853 in the Western Interconnection)
is mine. Have had their receiver for several years. Only downside is that i
can't record the data directly from the supplied receiver.
Jeremy
but what can you tell us about
The station at Santa Rosa, California (#853 in the Western Interconnection)
is mine. Have had their receiver for several years. Only downside is that i
can't record the data directly from the supplied receiver.
Jeremy
On Wed, Jul 3, 2019 at 12:01 PM Paul Theodoropoulos via time-nuts <
This stuff is fascinating to a time-nut-level:Novice such as myself.
While falling down the rabbit-hole searching on all the various bits of
the info below, I ran across this - not sure if you're aware of it, or
if it's old news, but it seems at least peripherally interesting:
Wow Tom that is great work! I won't pretend to understand what you did and
how you did it or, even, what the various graphs represent. But one thing I
get out of it is the amazing correlation of measurements made across such a
distance. And the equally amazing accuracy, stability, and
On 7/3/19 8:56 AM, Tom Van Baak wrote:
Bob,
Several of us do long-term measurement of mains frequency. We tend to
time-stamp cycles and then compute period or frequency, rather than
measuring frequency or period directly. Traditional counters in gated
frequency or time interval mode have
On 7/2/19 11:47 PM, Hal Murray wrote:
jim...@earthlink.net said:
Actually, it's because someone asked me about a science experiment where
you'd place them in a neighborhood outdoors.
Sounds like another science experiment: build an antenna to pick up 60 Hz.
You could start with the typical
Bob,
Several of us do long-term measurement of mains frequency. We tend to
time-stamp cycles and then compute period or frequency, rather than
measuring frequency or period directly. Traditional counters in gated
frequency or time interval mode have dead time and this will skew results.
In
Jim, almost any mains powered lighting has a substantial 120Hz component in
light intensity. It's quite reasonable to trigger off this at nighttime if
the light is on and only that single light is in field of view of a
phototransistor (no car headlights allowed to come into view!)
It's still far
On 7/2/19 10:09 PM, Bob Albert via time-nuts wrote:
I have tried to measure the power line frequency with spotty success. My
best results came from a period measurement, as many periods as the counter can
accumulate. Due to noise, one is never sure at quite what point the source is
jim...@earthlink.net said:
> Actually, it's because someone asked me about a science experiment where
> you'd place them in a neighborhood outdoors.
Sounds like another science experiment: build an antenna to pick up 60 Hz.
You could start with the typical ferrite, coil, and cap. Just adjust
I'd normally use an optocoupler.
But it doesn't need to be an 8-pin dip with the mains and low-voltage pins
0.3" apart - it can be a neon lamp and a photodiode, or a photodiode near a
mains-fed lamp. Even an incandescent has a very strong modulation of the
light. You just need to avoid leds that
I have tried to measure the power line frequency with spotty success. My best
results came from a period measurement, as many periods as the counter can
accumulate. Due to noise, one is never sure at quite what point the source is
measured. Perhaps a brick wall filter would clean it up for
On 7/2/19 4:09 PM, Dana Whitlow wrote:
I've always noted that casual attempts to pick up 60 Hz with small antennas
etc see more harmonics and other trash than actual line frequency. But if
you're in an office environment, why not plug something in? It's quite easy
to build a simple passive
I built a 6 Volt filament transformer into a small metal box and connected
the secondary to a couple of 5-way banana jacks. In addition to the 6 Volt
output, I put a 100KΩ pot across the terminals with the wiper connected to
a third jack. That way, I can have any voltage from 0 to 6 VAC, avoiding
Am 03.07.19 um 01:25 schrieb Tim Shoppa:
Jim, most of us are satisfied to use a 6.3VAC filament transformer to step down
from 120VAC and isolate from the power line.
Exactly. I used an old 6 or 9V AC wall wart and a resistive 1:3 divider
last year when the European grid frequency was low
Jim, most of us are satisfied to use a 6.3VAC filament transformer to step down
from 120VAC and isolate from the power line.
Tim N3QE
> On Jul 2, 2019, at 5:56 PM, jimlux wrote:
>
> There's some designs on the list (using a PICPET, for instance) to measure
> the local line frequency and
I've always noted that casual attempts to pick up 60 Hz with small antennas
etc see more harmonics and other trash than actual line frequency. But if
you're in an office environment, why not plug something in? It's quite easy
to build a simple passive diode clipper/filter that will plug into a
There's some designs on the list (using a PICPET, for instance) to
measure the local line frequency and phase..
but the schemes we've discussed require connecting to the power line in
some way.
What about a non-contact sensing approach? Something you could put in a
box and it would pick up
24 matches
Mail list logo
