The past few evenings and mornings I've been tuning my Radio Shack DX-394 into the Shortwave ham bands. The DX-394 is a pretty good radio if you live in a low signals area, as I do. I got my DX-394 a long time ago -- in 1998. It was made in March of 1997, about a year before they discontinued the DX-394.
That said, at least three times I've noticed this strange, noise anomaly just outside the top edge of the 20 Meter Ham Band. I also recently noticed the same -- or similar -- anomaly at least once in the middle of the 10 Meter Ham Band. The noise propagates, and there is some fading, which indicates it probably isn't local RFI -- although I won't rule that out, as I'm not necessarily an RFI expert (RFI is Radio Frequency Interference, for those of you who aren't SW Radio aficionados). Interference from your neighbor's house isn't going to fade from S0.5 to S4 and back down again, irregularly.
First I noticed this anomaly on 14356 kHz, just over a week ago. The second frequency where I heard it was 28191 kHz, and there the noise/signal was definitely fading, from S4 down to S0 and back up again, and it wasn't regular in its fading pattern. Ten minutes later when I checked for it, it was gone.
It's one of those mystery noises we Shortwave and Ham Listeners encounter when we tune the bands. Sometimes it can be a noise from your electronics in your home, or your neighbor's home, or even somewhere in your neighborhood. Some radios have internal noises that can interfere with genuine signals coming over the atmosphere. Some noises -- like Over The Horizon Radar (called 'OTHR' by SWL's) -- can have distant sources (like China, Russia, or the US) and be intermittent, and they do not always sound the same. They can sound like pulsing noises, or even buzzing noises -- as OTHR can be sent with different numbers of signal pulses per second.
There are also noises on the Shortwave bands that may be military or scientific in origin -- and there are SW enthusiasts who spend a lot of time trying to ID or track them.
I'm not one of those people. I can ID most of the sounds I heard on the Ham Bands (CW, USB/LSB, FT8, Olivia, RTTY, etc.), and I can ID the sound of an OTHR (usually), and I can ID coastal CODAR noises (which sound like sweeping noises that often cover wide swaths of the SW spectrum; it is used to measure ocean waves near the coastline), and a lot of RFI I can ID, but I can't always ID the stranger noises I hear on HF and SW.
UNIDENTIFIED JET NOISE -- PHASING AND PROPAGATING on 14356 kHz
And this is one of those occasions. It is a roaring, phasing, propagating 'jet noise'. It sometimes appears just above the 20 Meter Ham band. I asked a Radio forum about this -- I posted a question about the mystery noise on the HF Underground, an excellent forum for anyone who is a Radio hobbyist, DX'er, SWL, or SW anomaly enthusiast. One of the guys who responded asked if I had any recordings. I had made two recordings, taken from my phone -- so they sound tinny. The two clips, sounding as they do, are the best I've got. Being that I couldn't post them on the HFU site, and that I don't have a YouTube, I figured I'd post the clips here, for what it's worth.
Here's a link to HFU, for those interested. If you like SW or Radio DXing at all, there will probably be something of interest here on this site. The HFU Wiki also has a lot of info on the stranger stations and noises you'll often hear. I found out about the Desert Whooper using the Wiki on this site (as well as a thread dedicated to that cool sounding, 4096 kHz, mini-beacon).:
So, here are the clips of the 'Jet Noise', centered on 14356-14357 kHz, the first of which I took after 2 a.m. Pacific Time, about a week ago, on July 19th, UTC. This signal was fairly wide, ranging about 3-5 kHz each side of 14356 kHz. That is why on one clip the readout says 14356, the other says 14355 -- the signal is fairly wide in spectrum.
'Jet' noise, Radio Shack DX-394 + 25 ft. indoor wire, 14357 kHz, 0916 UTC (2:16 a.m. Pacific). July 19th, 2024.
'Jet noise', 14356 kHz, Radio Shack DX-394 (+ 25 ft., indoor, second story wire), July 17th, 2024, 11:05 p.m. Pacific, 0605 UTC.
A MYSTERY RTTY TRANSMISSION ON 14001 kHz
Here is another recording, that I took this morning, when I was tuning the high HF ham bands on my DX-394 again. This was in the 20 Meter Ham band -- some RTTY (Radioteletype / FSK sounds) at 14001-14002 kHz. I first noticed it around 1418 UTC (7:18 a.m. Pacific Time). It was propagating, and a weak signal, less than S1 on a scale of S1-S5. It was getting stronger and weaker as I listened to it. It was weaker when I checked it again at 1438 UTC. I did get a phone recording of it, so I am posting it here. As for the frequency being reported as 14001-14002, I never know exactly where to zero the signal, and even if I did, I can't read it anyway....
UNID RTTY/FSK, weak, inside the lowest reaches of the 20 Meter Ham Band, Radio Shack DX-394 + 25 ft. indoor, 2nd story wire; July 24th, 2024, 7:08 a.m. Pacific, 1408 UTC.
The reason this is interesting is because RTTY and FSK (Frequency Shift Keying, which is a term that covers all sorts of RTTY style modes) aren't allowed (or just aren't done) in the lowest part of the 20 Meter Ham band. Two to three weeks ago I heard a very loud RTTY / FSK station on this same exact frequency, around 2 a.m. my time, 0900+ UTC. Another DXer said he had logged that station also, and he believed it was some sort of 'intruder', which can happen in the Shortwave ham bands.
Being that the propagation would probably favor either the Western half of the US, or Asia, my guess is that this RTTY intruder may be Asian in origin, but that is just a guess. The times I've heard it, there usually is some Asian activity either on the 20 Meter ham band, or the SWBC bands are open to Asia.
These "intruder" stations can be fascinating to hear, be they ham pirates (illegal stations using the ham bands), or government and military agencies, and the like. The most famous intruders are the mysterious "Lima Pirates", operators who chant together on the airwaves (it's a type of game, actually), in the lower reaches of the 40 Meter Ham Band. I wrote about them in an article last month, which you can read here. The article also has some pretty good YouTube sound recordings of them.:
There are plenty of mysteries and anomalies that occur in the Shortwave spectrum. A lot of the strange sounding signals are explainable by those in the know. There are SWL's who thrive on recording and ID'ing these signals, usually lumped under the term "Utility Signals", because they serve a purpose other than entertainment -- they are military, aeronautical, scientific, or maritime transmissions.
Often you need special equipment to ID or otherwise decipher these signals, and many -- because of their military and governmental nature -- are not decipherable at all, but the experts usually can ID the type and mode of signal they are.
For the rest of us? You just learn to track them by ear and log them down. :-)
FIRING UP MY YAESU FRG-7!
Well, that's the latest Shortwave goings-on that have been happening here at my location. I still have an article on the DX-394 in the works, and I've also started one on my venerable 1979 Yaesu FRG-7, which I recently fired up again after years just sitting in the corner of my DX room.
After exercising the controls to clear the dust and oxidation from them, the radio worked perfectly! I am working on an article about it that I will post in a couple weeks. Here are two vid clips, one of an Indonesian ham sending Morse Code in the lower reaches of the 20 Meter Ham Band, and another clip of China Radio International's broadcast in Turkish.
This morning had a couple surprises. First off, the 40 Meter Band was mostly dead, except for some Californians talking on LSB on 7199 and 7185 kHz. 40 Meters is usually fairly open to Asia in the early mornings here.
The logo of a Brunei ham I heard earlier this morning on my DX-394, on 14013 kHz. Unfortunately, I wasn't able to get a recording of him. He sent good, clean CW/Morse code, and had a good, S1-S2, mostly readable signal. A little later I heard YB0E_T contacting US hams in CW also on 14013 kHz.
On 20 Meters, though, I heard the Indonesian ham, and a different guy contacting US and other hams in Morse Code, and he was in Brunei, sending Code on 14005 kHz. For those who aren't geographically savvy, Brunei Darussalam is a small, independent country on the northwest coast of Borneo, surrounded by Sarawak, East Malaysia. I looked up the ham after I logged his callsign, V85NPV, and V85NPV builds all of his own radios. Quite good, obviously, with electronics!
Here is a link to his QRZ page, where there are pics of all the radios he has built from plans, and from scratch.:
This following clip is of the Indonesian ham sending Morse Code early this morning. His call was YB0E_T (because of his fast sending speed and the fading I couldn't ID the entire call accurately) and he was looking for contacts with US stations. He had a solid CW signal both on my DX-394 and FRG-7, and got a few contacts, mainly from Californians. Here you can hear him sending "CQ USA". As you can tell, the FRG-7 is a great receiver for CW, although the bandwidth can be a bit wide for separating out signals. This particular a.m., there wasn't a ton of activity in that part of the 20 Meter Band to have to separate signals, though.:
Indonesian ham YB0E_T sending "CQ USA" in CW/Morse code. Approx. 14013 kHz, FRG-7, 25 ft indoor wire. After 1410 UTC.
This is a recording of China Radio International broadcasting to Turkey and the EU in Turkish. The location of the transmitter is probably Kunming, in Yunnan province in south central China. The frequency is 13710 kHz in the 21 Meter Band, and the time I heard this was 1504 UTC (9:04 a.m., Pacific Time):
Well, that's about all for this time around.
Until next installment,
Peace.
C.C. July 24th, 2024.
ADDENDUM, September 17th, 2024:
I neglected to update this article after a guy on HFU -- Thomas in Germany -- listened to my MP4 vid clips on here, and he said it sounded like a STANAG mode used by military (probably from an Australian military transmitter, at Humpty Doo, in northern Australia). The STANAG in question may be STANAG4285.
There are a lot of modes used by military operations, and STANAG is one of them. I'd heard of STANAG, but never learned to identify it. Apparently buried in the jet noise is a form of digital transmission.
Humpty Doo would fit, propagation-wise, as the time I heard the transmission was when the 20 Meter Band was open to Asia and Oceania.
Here's the link to the HFU thread I made about the 'Jet Noise'.:
A shout out to everyone from HFU who has visited the blog -- from my Stats page I can tell there are at least a couple. Peace.
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