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Author Topic: Shortwave sounds I've always heard.  (Read 2143 times)
KC6RWI
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Posts: 173




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« on: March 18, 2019, 09:58:01 AM »

Sadly I don't have a sample of what I am hearing, I'm sure others who have monitored 28 mhz and lower have heard this sound. Years ago I was told it was a diaphermy machine. I checked utube under odd shortwave sounds and I found some interesting and also dumb submissions. The sound I hear is a circular sound that starts low in frequency and rises up. I always imagine an a visual picture of an upside down hurricane, it also sounds similiar to the last bit of water going down a drain.  Maybe if someone has a good utube that might id this, I tried that first
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NO2A
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Posts: 1400




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« Reply #1 on: March 18, 2019, 12:12:41 PM »

For quite awhile I've heard something I can't explain on AM broadcast. It sounds like someone in a tunnel saying "Ahhhhhh" with kind of an echo to it. Can't remember the exact frequency, but I want to say around 650 KHZ. I've heard it on more than one radio, and more than one location. Maybe some kind of heterodyne? I only hear it once in awhile.     Huh
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KX4QP
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Posts: 367




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« Reply #2 on: March 18, 2019, 02:58:42 PM »

Diathermy was an old therapy which involved heating tissues with RF (as I recall it was in the VHF range, which penetrates better than microwaves).  The emission was generally unmodulated, so it should sound like a solid key-down CW tranmitter, only on above 10m band.  The devices didn't have anything you or I would call an antenna (most had a sort of can shaped device on a cable where most of the RF radiated), and I'd be very surprised if you could hear one more than a mile or so from the clinic that had it.

Also, AFAIK, they've been out of service for decades, since less hazardous methods of heating tissues came into favor (there's no high voltage in a heating pad, never mind a salts bath).
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KAPT4560
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« Reply #3 on: March 18, 2019, 03:20:19 PM »

 Medical diathermy and violet-ray machines were noises sometimes heard in residential settings. The more affluent patients could afford having them at home.

 The cyclic noises, like a squeaky wheel are probably older fax (facsimile) machines. I remember hearing them in the evenings above the AM broadcast band.

 The internet has taken away a lot of services that were previously done by radio.
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RENTON481
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Posts: 275




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« Reply #4 on: March 19, 2019, 10:22:44 AM »

If it's a squish sound it could be Jupiter.

I used to hear Jupiter a lot when monitoring 12 meters, 11 meters sideband, and monitoring 10 meters.

Jupiter puts out radio waves, and when you hear it on SSB it sounds like a second long squish noise.
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KC6RWI
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Posts: 173




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« Reply #5 on: March 21, 2019, 12:58:42 PM »

The diathermy idea was something I heard years ago and they still make them, in fact when I looked last week 3 freqs where mentioned, one being 27.12 mhz. I've searched the utubes for sounds and nothing matches, I think I am probably hearing some sort of radar signal. The utubes of radar and usually continuous cycles of sound, The sound I hear appears to random to me and just one quick cycle. I'll try to get a recording.
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KC6RWI
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Posts: 173




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« Reply #6 on: March 21, 2019, 04:11:35 PM »

Found it, its posted on this link, the signal I hear starts low and goes high in sound, this is backwards but it possibly the same thing, Still no mention of what it could be, and I only hear once signal in long time.
https://www.youtube.com/watch?v=zFvDA5_msnM
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NO2A
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Posts: 1400




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« Reply #7 on: March 22, 2019, 08:20:07 PM »



If it's a squish sound it could be Jupiter.

I used to hear Jupiter a lot when monitoring 12 meters, 11 meters sideband, and monitoring 10 meters.

Jupiter puts out radio waves, and when you hear it on SSB it sounds like a second long squish noise.
I've heard that too while operating on the bands. Never knew that could be Jupiter. Curious what that would sound like on AM. I've never heard it below the amateur bands.
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RENTON481
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« Reply #8 on: March 25, 2019, 05:38:17 PM »

Found it, its posted on this link, the signal I hear starts low and goes high in sound, this is backwards but it possibly the same thing, Still no mention of what it could be, and I only hear once signal in long time.
https://www.youtube.com/watch?v=zFvDA5_msnM

That sounds like Jupiter.
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KC6RWI
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Posts: 173




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« Reply #9 on: March 26, 2019, 01:14:03 PM »

Yeah, thats the bands I would be monitoring. I am going to search it out and put it to rest. That sample very close, but when I hear it, its once and random. I used to think the band was changing when I heard, but maybe that was just coincidence.
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KE5HVM
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« Reply #10 on: March 28, 2019, 10:04:46 AM »

Super interesting!
I love RF-sleuthing.

Regarding Jupiter, it will depend on whether Jupiter was above the horizon at the time of your observations.

Here is a great link to listening in to Jupiter:
https://radiojove.gsfc.nasa.gov/

Gerrit
KE5HVM
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KC6RWI
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Posts: 173




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« Reply #11 on: March 29, 2019, 12:30:59 PM »

Its interesting, something somewhere is out there is making that signal, its been there for decades, I always thought it was an indication of propagation. Its not wave like sounds like from the link you posted.
Years ago when everything was analog, I had my scanner on in metro Los Angeles, there was so much to pick up on vhf. I got a signal close by me on 168mhz. It was audio from body mic, I put on my jacket and hid my scanner and followed the signal, it came from a store front income tax office. Walking back and forth I covertly took off my antenna and it still was there. There was nothing for me to do but head back to work.   
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NO2A
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« Reply #12 on: March 29, 2019, 04:09:11 PM »

Does our own Sun send any audible sounds?
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KAPT4560
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Posts: 552




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« Reply #13 on: March 30, 2019, 03:23:23 AM »

 Outer space is rife with noise across the entire electromagnetic spectrum. Just like having a bad neighbor  Grin:

 https://www.jpl.nasa.gov/multimedia/sounds2/index-nasa.html

 https://space-audio.org
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SM0AOM
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Posts: 254




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« Reply #14 on: April 05, 2019, 06:36:00 AM »

Diathermy was an old therapy which involved heating tissues with RF (as I recall it was in the VHF range, which penetrates better than microwaves).  The emission was generally unmodulated, so it should sound like a solid key-down CW tranmitter, only on above 10m band.  The devices didn't have anything you or I would call an antenna (most had a sort of can shaped device on a cable where most of the RF radiated), and I'd be very surprised if you could hear one more than a mile or so from the clinic that had it.

Also, AFAIK, they've been out of service for decades, since less hazardous methods of heating tissues came into favor (there's no high voltage in a heating pad, never mind a salts bath).

Having a brief medical electronics background, I can give some more background.

"Diathermy" is a broad term, and there are a lot of different applications in different medical disciplines.

First, we have surgical diathermy, where RF is used to cut through tissue, stop bleeding by "welding" blood vessels shut and coagulate blood at the same time. This usually operates in the "few" MHz range and with power ranges around 10 - 200 W. Some internal surgeons use this method a lot.

Second, the "general heating" application where muscles and joints are heated through dielectric heating using RF generators usually around 27 MHz and in the "several hundred watt" power range.
This is intended to counter inflammatory diseases and reduce pain by increasing the blood flow in the tissues. It has fallen somewhat out of use due to improved medication, but may still be encountered.

Then we have the "localised heating", where UHF or microwave energy is used to heat small sections of the body locally. 433 and 2450 MHz were the frequency bands I heard about in the 70s.

This technique seems to have been largely abandoned due to safety concerns, I remember my lecturer mentioning the risk of blinding patients due to overheating of the retina and optical nerve when trying to treat ear and nose infections (sinusitis).

Another application was heat treatment of urinary bladder cancer using small antennas on 2450 or 5600 MHz that was placed directly onto the tumors. This was the subject of an MSEE Thesis written by one of my friends at University.


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