4 Hz

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GoldDigger said:
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.

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Great, now I am starting to see stuff like VOP, FFT, bode plots, side bands, harmonics and other junk in my head. Aaaahhhh! Stop!
 
jumper said:
And that is a loooooonnnngggggg time when you need to speak to a nuclear sub skipper during the Cold War.:D
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"LAUNCH" would take 53 pulses, putting aside GoldDigger's comments for the moment, assuming a 3-dit space between letters, so about 14 seconds. ;)
 
gadfly56 said:
"LAUNCH" would take 53 pulses, putting aside GoldDigger's comments for the moment, assuming a 3-dit space between letters, so about 14 seconds. ;)
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Or if you make the totally reasonable assumption that variable length codes are used for specific messages in order of urgency, rather than just encoding alphanumeric characters, and even adding in a lot of redundancy (error correcting coding) given the importance of the message, one iteration of "LAUNCH" could take as few as 10 pulses.
 
GoldDigger said:
Or if you make the totally reasonable assumption that variable length codes are used for specific messages in order of urgency, rather than just encoding alphanumeric characters, and even adding in a lot of redundancy (error correcting coding) given the importance of the message, one iteration of "LAUNCH" could take as few as 10 pulses.
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What I don't know about information theory could probably fill several very large books (OED-size). I was trying to reduce it to terms even that run-of-the-mill folks, at least regarding comms theory, such as moi, could easily grasp.
 
GoldDigger said:
Or if you make the totally reasonable assumption that variable length codes are used for specific messages in order of urgency, rather than just encoding alphanumeric characters, and even adding in a lot of redundancy (error correcting coding) given the importance of the message, one iteration of "LAUNCH" could take as few as 10 pulses.
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Back when ELF was in the planning stages for the UP, we were told it would be like a pager. The presumption, was a coded message would basically tell a sub captain to stop 'running silent and deep' and to contact home immediately.
 
180222-1109 EST

More experiments.

I am using my scope on its 1 or 0.5 mV vertical range per division, and the horizontal 100 mS/division.

With just my coil and 2 ufd capacitor a Costco 4' LED produces excessive noise and I can't see any signal except the LED noise. So I turn it off and use a flashlight.

This morning I added an RC low pass filter, 100k and 1 ufd, This basically eliminates the Costco noise, and I don't see my low frequency signal either. So what I have been seeing that looks like 4 to 10 Hz may be a higher frequency carrier with some low frequency modulation.

Next step was to add a diode for non-linearity and a 100k resistor to the coil from an audio oscillator to make a crude superhet. At an oscillator frequency of about 75 Hz I do see bursts of energy at times, and with timed spacing.

This is a total deviation from my at stray 60 Hz magnetic field tests.

.
 
170222-2513 EST

Looking more at signals from my coil I have found bursts of enery at times.

Three periods I have seen are:

1. 200 microsec, 5 kHz.

2. 400 microsec, 2.6 kHz, may result from phase modulation

3. 150 microsec, 6,67 kHz.

Where might these come from? Timing apears to be very precise to these values. Then there are some much longer times associated with these same signals. These signa;s are created by someone.

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180223-0645 EST

jumper:

I have one LED 4' fixture over my bench where the oscilloscope is located. This is the only 4' LED I have, and it creates a sever amount of RFI. This came from Costco so it is my Costco LED.

I see there were a number of typos in my post #30. The 2.6 kHz should be 2.5 kHz a precise relation to the 5 kHz. 100 mS needs an "is" before the 100. "at" does not belong before "stray".

.
 
gar said:
180223-0645 EST

jumper:

I have one LED 4' fixture over my bench where the oscilloscope is located. This is the only 4' LED I have, and it creates a sever amount of RFI. This came from Costco so it is my Costco LED.

I see there were a number of typos in my post #30. The 2.6 kHz should be 2.5 kHz a precise relation to the 5 kHz. 100 mS needs an "is" before the 100. "at" does not belong before "stray".

.
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Thanks.

I read the thread so quickly earlier I thought Costco LED was was some electronic gizmo name like Zener diode or something.:ashamed1:

I had reread it again later and then it kinda dawned on me, the store.:slaphead:

I’m really that bright at times.
 
K8MHZ said:
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/
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They aren't coming from me, I always have my aluminum foil hat on. I find them to be both comfortable and stylish.

It might be interesting to note that a group of MIT students actually did a study on the efficacy of such headwear and found that these actually amplified some frequencies. Hmmmm, maybe these are my brainwaves you are picking up amplified by my rather stylish bonnet. It kinda makes you think.......
 
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