Oddity on WWV's 10MHz frequency June 30, 2022 05:10Z

[13dka]

Going through last year's recordings I found this odd appearance of what sounds like 2 stations on top of WWV 10 MHz:



As you can see on the video, I frantically tried to make sure that this is not some odd malfunction of my IC-705. I have an audio recording with the weaker of the 2 stations transmitting an unknown interval music a bit later around 05:19Z, then both stations faded out within 5s on 05:20Z.

Seems obvious that something went wrong somewhere, what exactly that was is a funny mystery though - AFAIK there are no "feeder" stations anymore, sending programs to relay stations or something, which the mix of 2 stations may suggest. The 2 signals disappearing together indicates that it was a single transmitter for the signal(s) though.

I could imagine that a transmitter for the 31m-band was accidentally tuned to 10MHz, but that wouldn't explain the 2 different signals, some external intermodulation would be an interesting thought but how would that end up precisely on 10 MHz? Well, maybe somebody has some insights or interesting speculations/theories to share?

[Andrew (grayhat)]

The first thing which popped to my mind was the "Luxembourg effect", but I sincerely doubt it may be the case, although it can't probably be excluded; a secondo cause may be due to some "manteinance" performed on transmitters, in such a case during a tuning/alignment/testing procedure some spurious signals may have been generated and then suppressed once the operations were completed

[13dka]

Here's the minute before the stations disappeared (with the rapid fadeout after the second minute beep), and the sign off music I can't seem to identify (I'm not so much of a BCL I'm afraid and YouTube has only historic interval signals):



WWV didn't have much of a signal to be modulated that much through the Luxemburg effect, so that's likely not it. Well, it's just one of these odd things you encounter on SW sometimes anyway and likely just some transmitter cock-up, there's no point in finding out what it was besides curiosity.

[Egil - LA2PJ]

I do no recognise the languageof the announser, but the music in the background is the interval signal of Vatican Radio. I have no idea how this could happen though, so you have probably recorded a once in a lifetime happening.

[Egil - LA2PJ]

I just had an eye opening experience. When I commented on 13dka' recording, I was sitting in a hotel room in Trondheim using my laptop.
Think I have to purchase some kind of bluetooth earbuds to get proper audio quality. WhenI listened to his recording again, after returning home tonight, I immediately recognized the language as english. My home computer is connected o a pair of high quality stereo speakers since I use it for editing audio recordings all the time.
But still I don't understand what phenomenon he has recorded.

[13dka]

Yes, it's English but alas very much drowned out by the stronger program and unintelligible. Are you sure this is Radio Vatican? Are they having a different interval music for sign-off? It's very similar, even in the same key as it seems but it lacks the glockenspiel/vibraphone/xylophone/dingdong lead and the chords are a bit different than the known RV interval signal. Maybe it's meant to sound similar, it does sound very much like belonging to some religious program.

Maybe the 2 apparently very different programs in very different signal strengths points to one of the airtime broker stations somewhere, maybe the power went out and their exciters were reset to 10,000.000 kHz, or coffee was spilled so early in the morning...

BTW, I often don't follow my own advice and listen to things (where that really counts) on whatever the device has for speakers, but the difference a good pair of cans or a good speaker makes can be quite dramatic, and by "good" I don't mean necessarily "expensive": For example, I have a pair of cheap China-made AKG cans (real AKG headphones are no more) that don't really cut it for proper hi-fi but they are just right for radio - they have all the bass range one would want for MW music stations and to harvest all the signal energy some hams put into broadcaster style low end processing (often too much of it), and the underdeveloped high frequency response doesn't matter on shortwave and is just right to keep hiss etc. away. For "grassroots" DX fans or MW DXers some cans (ideally "closed" style for minimum distractions) are an essential tool.

[Andrew (grayhat)]

as for cans, I've these

https://www.oneodio.com/products/a71-st ... headphones

bought them time ago, they were discounted, pretty nice response and good isolation, they're also available on amazon, also notice that if desired, it's possible to buy an additional boom mic for these phones

https://www.oneodio.com/products/a71-ad ... es-black-1