A while back, when activating ES-054 W4ZV Bill called in with an echo on his cw, it was noticeable but there wasn’t a gap between the genuine rf and the echo. N4EX called 10 minutes earlier and didn’t have an echo.
Well, today it was reversed, Bill called 6 minutes before Rich without an echo. Rich had a very strong echo, and the gap was noticeable. I was working on 17m today, but on ES-054 it was 20m.
I guess others have also experienced it, I’ve only noticed echoes when /P myself.
Ian MM0GYX
In reply to MM0GYX:
Long path?
73
Brian G8ADD
In reply to G8ADD:
I guess so, not experienced it much myself. Just wondered if it was common for other activators. I had read about a similar effect, that was caused by the magnetosphere though.
73,
Ian
In reply to MM0GYX:
Long path right around the world including 'skips’
should only take around 1/7 sec, so would only give an echo effect.
A friend mentioned to me recently that he had heard an effect on 40 metres
when a couple of words would repeat, This was at night, and while the effect
lasted, applied to several stations across the band. Anyone any ideas?
73,
Dave
Several years ago, OM Wolfram, DL1RXA, sk, made regular experiments with “round the world propagation” of short wave radio signals, and he observed signals that had circled around the globe up to 3 or 4 times. It takes 133 to 138 msec for an electromagnetic wave to travel around the earth, and cw signals can become nearly unreadable by the repeated echos. I still have audio recordings of one of his tests, which I would be happy to share with anybody interested. (mail at call@darc.de)
Obviously there must be some sort of ionospheric ducting (“Pedersen Ray”) to explain the relatively high signal strength of these far travelled signals.
The “long delayed echos” are another story. There have been reports in literature dating back to the early days of radio science of echos with a delay of several seconds up to 260 seconds. This phenomenon has been observed and reported of only rarely and as far as I know, no accepted explanation of this kind of propagation exists. Of course, “fake” always has to be considered but there might be other rare and not yet fully understood effects in ionospheric propagation.
73, Martin, df3mc
In reply to DF3MC:
There is a ham doing research into long delay echoes (LDE) who has contributed a couple of articles on the subject to Radcom, I’ll look them out when I get time and give the references here. There is one regularly observed LDE mode that works best at about 2 megs and involves a local signal following the lines of magnetic force to the southern hemisphere and reflecting back. As Martin says, the very long delay echoes are a mystery. If a simple echo the reflection must be somewhere near the moon’s orbit!
73
Brian G8ADD
In reply to G8ADD:
I’ve had this experience on 28mhz cw a few times. Someone once called it multi path propagation. The countries higher in latitude or closer to the north pole end of the globe seem to echo much louder. Yes it is hard to read the cw when you hear the same characters more than once, and maybe also the higher power stations amplify the effect. But it is also a very nice sound too to listen to,
being a cw lover…
73
Ian vk5cz …
In reply to MM0GYX:
Thanks for sharing your thoughts gents, it’s certainly a curious effect. I wonder how long it would’ve lasted if the qso was much longer, also how local the effect might be. Andy, MM0FMF was on a nearby hill (abt 100km away), he worked N4EX also on 17 metres at 1514z, that’s 1hr 49m later. I’ll ask him if he noticed anything.
Like I said, I’ve only noticed the echo twice in my short time as a ham, both from hill tops. This is obviously far too few times to draw a conclusion and likely just coincidence.
It did make the cw slightly more difficult to read, but then that’s relative as I don’t have the best ears!
73,
Ian MM0GYX
In reply to MM0GYX:
A while back, when activating ES-054 W4ZV Bill called in with an echo
on his cw, it was noticeable but there wasn’t a gap between the
genuine rf and the echo. N4EX called 10 minutes earlier and didn’t
have an echo.
I have recently had the very same effect with Bill’s signals.
I’m not sure what he’s using but, of late, he’s been packing an almighty punch and often with a very noticeable echo.
I think the first time I noticed this effect was on SW/009.
When he called me he was so loud, which together with the unusual echo, made me think he was someone local overloading my front end.
I actually glanced round to see if someone had sneaked up and was working form my hilltop 
I sent GW4ZV? as I was convinced I’d missed the G and the end of the suffix!
I’ve only ever noticed this echo on Bill’s signal, not on Rich’s.
Rich is always a consistent signal, and usually the first Stateside in the log, but in the 17 times worked, I’ve only given him 599 once as opposed to 6 times out 10 for Bill.
Certainly an interesting phenomena and interesting that it occurs form the same station.
Pete
In reply to MM0GYX:
Ian, I mentioned the very same effect in an email to Barry, N1EU, after a contact on 6th January from Great Coum G/NP-011 on 20m at 1352utc.
The signal from Barry sounded like it was ‘3D’, it actually made copying easier as the signal sounded to be in my head rather than the two sides from the earbuds. I guess the phasing was just ‘right’ to simulate a ‘stereo’ effect.
The effect was still there for my contact for Rich N4EX a few minutes later, but not as marked.
I find this subject fascinating, although I am also a bit in the dark about radio propagation.
73, Colin
In reply to G4ISJ:
Pete and Ian,
I got so tired of hearing you guys (using a Beverage) but not getting any response (with 100W to a broken 10m Yagi thru a tuner) that I put up a proper antenna for 20/30m. It’s a simple inv-V up about 18m and oriented East/West. On 20m to Europe, I often use an amp to get through the big pileups over there, so most likely it was on 20m that you heard strong echoes. The antenna also works well on 30m but I only run the K3 barefoot there (100W).
The echo you hear is probably either long path (since my TX antenna is bi-directional) or possibly multi-path if conditions are disturbed. I don’t normally hear this on received signals since I’m using a very directional Beverage to EU. However last November 3, during an activation of W4C/EM-047, I was using a 44’ doublet oriented NE/SW. On 15m from 1345-1421z I worked ~30 Europeans and had severe echos on most. I’m fairly certain this was long and short path simultaneously since my antenna was oriented perfectly for that and I was only using it for receive. And 15m is notorious for this sort of thing!
I hope this may help explain what you’re hearing on my signal. I’m eventually going to get my old KT-34XA back up at 30m and that should reduce the echoes due to its better directivity.
73, Bill W4ZV
In reply to W4ZV:
Hi Bill, for the benefit of others - we had an email exchange about your echo a while ago, I noticed it twice now I come to think about it. I started this thread just to share it with others and thought it worthy of discussion.
You didn’t have the echo yesterday Bill, it was Rich’s turn!
Colin has described what I heard the first time well, it was much like a ringing tone. Yesterday was different, there was a perceptible gap, which made the copy a little odd.
As for signal reports, I give S9 if I can sense the AGC working hard so it’s normally 559 - 579 for Bill and 539 - 559 for Rich.
I still find it amazing that much less than a watt is all that’s required to be heard almost 4000 miles away.
73,
Ian MM0GYX