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Old 22nd Sep 2020, 5:02 pm   #1
radioman
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Default Echo on short-wave station

Last Sunday, I heard a station in the 19m band on 15770kHz using my Trio R-5000 receiver.
It had a weird echo effect and I'd be interested to know what you think could be the cause of this.
I've posted a video onto YouTube here :- https://youtu.be/ex23MV_vPNQ so you can have a listen.

Andy
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Old 22nd Sep 2020, 5:11 pm   #2
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Default Re: Echo on short-wave station

Do not think it will be an Aurora at that frequency.
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Old 22nd Sep 2020, 5:38 pm   #3
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Default Re: Echo on short-wave station

Hi,

I remember hearing that type of 'echo' many years ago. It could be a combination of
both long and short path reception.

Kind regards
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Old 22nd Sep 2020, 5:47 pm   #4
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Default Re: Echo on short-wave station

Weird isn't it? I think that's far too long for long and short path reception which has a delay of about 0.14 seconds. What you're hearing is from two different transmitter sites intending to beam to different zones. Each site's audio is fed via a different route; one may be satellite, the other an internet link, or two different internet links and the audio has all sorts of digital delays.

Propagation at the time and your location means you can hear both signals. This phenomenon gets reported from time to time. I helped them unpick it on the 'Soldersmoke' podcast a few years ago.

Ian

PS: There is also the very odd phenomenon of long delayed echoes with delays of many seconds. Unfortunately it's vanishingly rare with no plausible mechanism - so tends to be put in the "can't be explained, too rare so doesn't exist" box! I think there are some theories now and it's being accepted as a real phenomenon.

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Old 22nd Sep 2020, 6:57 pm   #5
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Default Re: Echo on short-wave station

Listening again, the two voices seem to fade up and down at the same time suggesting they come from the same transmitter. It appears to be WRMI Okeechobee - just one transmitter site. Maybe they had two feeds (main and standby) plugged in at the same time by accident...?
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Old 23rd Sep 2020, 2:56 pm   #6
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Default Re: Echo on short-wave station

Thanks everyone for your thoughts about this.
Many possibilities but I guess we'll never know for certain !

Andy
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Old 23rd Sep 2020, 4:44 pm   #7
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Default Re: Echo on short-wave station

There are numerous possibilities.

Long path versus short path

Two transmitter sites covering different geographies without mention of each in the other's area.

Space aliens

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Old 24th Sep 2020, 1:03 pm   #8
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Question Re: Echo on short-wave station

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Originally Posted by Ian - G4JQT View Post
There is also the very odd phenomenon of long delayed echoes with delays of many seconds.
Round the world propagation, assisted by ducting and inter-layer reflections?

AL.
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Old 24th Sep 2020, 2:18 pm   #9
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Default Re: Echo on short-wave station

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There is also the very odd phenomenon of long delayed echoes with delays of many seconds.
Round the world propagation, assisted by ducting and inter-layer reflections?

AL.
That's one theory, but the losses of that mode are estimated to be much more than those observed.

The phenomenon has a long history going back to the 1920s - with one scientist linking them with an alien Bracewell probe.

A German radio amateur managed to record an example (or claimed to) from his own transmissions in the past decade or so, but got so much flack from the we-can't-explain-this-so-it-must-be-fake brigade he removed it.

Not an attitude conducive to researching erratic and not understood stuff. But an attitude that many people embrace...

Wikipedia has some sensible stuff about LDEs.

https://en.wikipedia.org/wiki/Long_d...ive_hypotheses
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Old 24th Sep 2020, 9:55 pm   #10
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Default Re: Echo on short-wave station

I thought the same as Al
however, I take your point about losses Ian.
The conditions higher up in frequency were unusual that weekend - a radio amateur pal of mine had a contact with a German station on 2m SSB using 100W.

Andy
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Old 27th Sep 2020, 11:29 pm   #11
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Default Re: Echo on short-wave station

I'd just read this thread before going to bed the other night, and then I turned on a portable I keep in the bedroom to check if there was any lightning going on locally. Switching to MW it landed on a random channel with the most wonderful collection of echos and pre-echos of Spanish speech. Tonight I found the channel on something with digital readout and it turns out to be RNE 5 on 1125 with, appropriately 5 tx all 10kW
Not quite as echoey but still noticeable
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Old 28th Sep 2020, 9:33 am   #12
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Default Re: Echo on short-wave station

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I'd just read this thread before going to bed the other night, and then I turned on a portable I keep in the bedroom to check if there was any lightning going on locally. Switching to MW it landed on a random channel with the most wonderful collection of echos and pre-echos of Spanish speech. Tonight I found the channel on something with digital readout and it turns out to be RNE 5 on 1125 with, appropriately 5 tx all 10kW
Not quite as echoey but still noticeable
You can get the same effect on some UK commercial stations. The 'echoes' are created by multiple stations in a network all getting their audio feeds by different routes. They even have different local ads in the breaks!

The modern thinking is that in the daytime service area, you only hear the signal from your intended transmitter. Unfortunately, night sky-wave interference allows you to hear other stations on that frequency. Spain is a good case to demonstrate this because they use many local MW transmitters for their national networks and they don't bother with synchronising the audio.

I'm sure retired BBC transmitter engineers will remember how not only were all MW network transmitters' carriers kept to 0.05 Hz, but the audio was in phase (as far as possible) that fed each transmitter. That was easier when the modulation came down analogue 'music lines'. These days it's a dog's dinner of digital feeds - and no one cares how it sounds.

I think Five Live isn't quite as bad, but I don't think the network frequency sync is kept to 0.05 Hz, neither is as much attention kept on the phase of each transmitter's modulation as was the case in the 1980s...

Ian
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Old 28th Sep 2020, 9:42 am   #13
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Default Re: Echo on short-wave station

Group sync +/-0.05Hz ... nicely remembered, Ian
Guy

"Oh, hearing Okeechobee ...
Oh, hearing Okeechobee ...
Oh, hearing Okeechobee -
That's what it's all about"

(sorry, couldn't resist it)
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Old 28th Sep 2020, 12:03 pm   #14
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Default Re: Echo on short-wave station

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Oh, hearing Okeechobee ...
Oh, hearing Okeechobee -
That's what it's all about...'
It was 0.05Hz on MF transmissions, but on synchronised HF transmissions it was 0.005Hz. Non-sync HF the limit was 5Hz, but we were always tighter than that, oh yes.

I'd be keeping that left leg in if I were you...
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Old 28th Sep 2020, 1:18 pm   #15
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Default Re: Echo on short-wave station

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I'd be keeping that left leg in if I were you...
Have you heard Bill Bailey's Kraftwerk version?

Brilliant!

https://www.youtube.com/watch?v=dwaxWoJPUC0

David
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Old 28th Sep 2020, 1:27 pm   #16
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Default Re: Echo on short-wave station

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Originally Posted by Radio Wrangler View Post


Have you heard Bill Bailey's Kraftwerk version?
I have now! Brilliant indeed.

Did he ever come home, Bill Bailey? Did he ever come home? Is she still moaning the whole day long?
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