4 Hz

[gar]

180221-1437 EST

Who is transmitting at 4 Hz or thereabouts. I suspect Russia or US for under water communication.

In playing with measurement of stray magnetic fields I noticed a change in the background level. I was reading in the 20 micro volt level (a relative measure), then it jumped to 40 to 50 microvolts. Put this on a scope and it is not random noise, but a carrier of some sort around 250 milliseconds period.

The signal is detectable and measurable, and it will be everwhere. So this is something that should bother all those hyper-electromagnetic field sensitive people.

A little later the frequency seemed to change to around toward 10 Hz. Now it is mostly gone and I am back to a 10 to 20 microvolt noise level.

I am using 1500 turns on the coil and a Beckman 4.5 digit meter that resolves 10 mictrovolts.

.

 

[jumper]

ELF signal for Subs was 76 Hz.

https://en.m.wikipedia.org/wiki/Project_Sanguine

4 Hz, no clue.

 

[al hildenbrand]

The Wikipedia article on ELF suggests, that, among other things, pipeline inspection gauges, PIGs, use ELF to broadcast through the pipe walls. . .

 

[gar]

180221-1516 EST

jumper:

I was aware of the higher frequencies in the Wiki discussion.

The signals I saw today were definitly modulated in some fashion, and did have some kind of carrier frequency component. The magnetic field was directional.

.

 

[jumper]

180221-1516 EST

jumper:

I was aware of the higher frequencies in the Wiki discussion.

The signals I saw today were definitly modulated in some fashion, and did have some kind of carrier frequency component. The magnetic field was directional.

.

ELF simply popped into my head from communication courses in college.

I wasn’t trying to say that was what you had but, rather eliminating that as a possibility.

 

[gar]

2180221-1531 EST

jumper:

It was good that you mentioned the Wiki article.

When I saw this very low frequency signal today it was quite surprising in light of the ballpark 80 Hz signals.. In some ground voltage measurements (effectively a current measurement) I made in the past I have seen some low frequency signals and wondered the source.

.

 

[jumper]

Just thought of it.

4 Hz, that makes the wavelength about 75,000 km long. Wow!

 

[GoldDigger]

Just thought of it.

4 Hz, that makes the wavelength about 75,000 km long. Wow!

Which is what gives it the (relatively) great penetration even into salt water.

But an E-field based rather than B-field based antenna could be a little hard to drag around. :angel:

 

[jumper]

Which is what gives it the (relatively) great penetration even into salt water.

But an E-field based rather than B-field based antenna could be a little hard to drag around. :angel:

I know that the messages better be reaaaaalllllyyyy short or one would die of old age waiting for all the info.

 

[JFletcher]

Earthquake? Earth moving equipment? Neighbor with a 36 inch subwoofer? 4 HZ is too low to be heard so I don't know I doubt it would affect anyone even sensitive to electromagnetic fields. ETA ... On second thought project HAARP possibly Airport communications who knows

 

[K8MHZ]

Brain waves?

Theta brain waves are considered brain waves that oscillate between the frequencies of 4 Hz to 8 Hz (cycles per second).

https://mentalhealthdaily.com/2014/04/12/theta-brain-waves-4-hz-to-8-hz/

 

[jumper]

Brain waves?

Theta brain waves are considered brain waves that oscillate between the frequencies of 4 Hz to 8 Hz (cycles per second).

https://mentalhealthdaily.com/2014/04/12/theta-brain-waves-4-hz-to-8-hz/

Note to self: Kate may be crazier than me.....scary thought.........

 

[drcampbell]

Earth's Schumann resonances begin at 7.8 Hz, but I'd expect random modulation.
https://en.wikipedia.org/wiki/Schumann_resonances

 

[jumper]

Earthquake? Earth moving equipment? Neighbor with a 36 inch subwoofer? 4 HZ is too low to be heard so I don't know I doubt it would affect anyone even sensitive to electromagnetic fields. ETA ... On second thought project HAARP possibly Airport communications who knows

Not HAARP I think. Wrong frequency.

The HAARP project directs a 3.6 MW signal, in the 2.8–10 MHz region of the HF (high-frequency) band, into the ionosphere.

https://en.m.wikipedia.org/wiki/High_Frequency_Active_Auroral_Research_Program

 

[jumper]

Earth's Schumann resonances begin at 7.8 Hz, but I'd expect random modulation.
https://en.wikipedia.org/wiki/Schumann_resonances

Interesting.

I didn’t know about this

or if I did, I forgot.

 

[GoldDigger]

Interesting.

I didn’t know about this

or if I did, I forgot.

Just doesn't resonate with you, eh? :slaphead:

 

[jumper]

Just doesn't resonate with you, eh? :slaphead:

That was a good one.

 

[gadfly56]

I know that the messages better be reaaaaalllllyyyy short or one would die of old age waiting for all the info.

Straight key telegraphers could send up to 25 words per minute, each standard word being 50 dots and the standard word gap being 5 dots. If the dot length is taken as crest to crest or trough to trough, that would be 50x25 plus 5x25, or 1,375 pulses per minute or about 23 Hz. So, about 1/6 the speed of an old-time telegraph operator.

 

[GoldDigger]

Straight key telegraphers could send up to 25 words per minute, each standard word being 50 dots and the standard word gap being 5 dots. If the dot length is taken as crest to crest or trough to trough, that would be 50x25 plus 5x25, or 1,375 pulses per minute or about 23 Hz. So, about 1/6 the speed of an old-time telegraph operator.

The modulated carrier is not really equivalent to an interrupted DC signalling circuit, so your estimate of the information rate of the 4Hz signal could be off by a factor of two or more in either direction depending in the modulation/encoding scheme selected.
For straight Amplitude Modulation the data rate is going to be lower than the carrier frequency, but for complex amplitude/phase/frequency modulation the data rate can be even higher than the carrier frequency. One example is a 38-56K bit per second modem using a 2400Hz carrier frequency.

Sent from my XT1585 using Tapatalk

 

[jumper]

Straight key telegraphers could send up to 25 words per minute, each standard word being 50 dots and the standard word gap being 5 dots. If the dot length is taken as crest to crest or trough to trough, that would be 50x25 plus 5x25, or 1,375 pulses per minute or about 23 Hz. So, about 1/6 the speed of an old-time telegraph operator.

And that is a loooooonnnngggggg time when you need to speak to a nuclear sub skipper during the Cold War.