[Elecraft] LDEs (Long-Delayed Echos)

[Poul Erik Karlshøj (PKA)]

Hi Ted
You can hear quite strong echoes on low bands (maybe up to about 5MHz as far as I remember). Signals follow earth magnetic field - bouncing back when they reach the southern hemisphere -  and the delay therefore depends on your magnetic latitude (distance from the magnetic pole). It is quite a long path and for my QTH the delay is 237 msec which is so long that it is easy to hear your own echo with any modern rig. In fact you would think someone is jamming you until you find out its yourself! The phenomenon has been researched and is well understood.

It seems to occur around winter solstice and I have heard it several times, mostly 4 to 5 hours after sunset. I wrote an article about it in QST Nov 2009 (Observation of Long Delayed Echoes on 80 Meters) and I can send you a copy if you mail me off-list. I can also send you an audio recording so you can hear what it sounds like. Anyone else who wants a copy (article and/or sound recording) please contact off-list.

Good luck - I expect chances will be best on 80m in a few weeks time from now on until around February.

73/Paul
OZ4UN

Sent from my iPad

> On 28 Nov 2015, at 04:38, Dauer, Edward <edauer at law.du.edu> wrote:
> 
> I just finished reading Eric Nichol’s (KL7AJ) book titled Radio Science 
> for the Radio Amateur, in which LDEs and other non-linear propagation 
> events are discussed (ch. 11).  Eric considers some of the proposed 
> explanations but concludes that none of them really work.  I heard it 
> myself once on HF, during the sunspot peak many years ago.  As I remember 
> it, the delay was about 1 to 2 seconds.  Truly spooky.
> 
> Ted, KN1CBR
> 
>> Message: 18
>> Date: Thu, 26 Nov 2015 19:54:40 -0800
>> From: Jack Brindle <jackbrindle at me.com>
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] P3 Showing Transmit Signal
>> Message-ID: <D810200A-586F-4CBA-ADA1-C1F7F17FA0DE at me.com>
>> Content-Type: text/plain; charset=utf-8
>> 
>> That would be from me? Amazingly, this was on 80 meters, and was heard 
>> all over the bay area up into central CA. At times the ?echo? was louder 
>> than the direct signal!
>> There are at least two recordings from that event. Very strange, and 
>> extremely interesting. While it was ongoing, both 40 and 80 were open 
>> across NA. When it stopped,
>> 40 collapsed to the point where the only signal heard was VY1AAA, and 80 
>> became only local. In 40+ years of hamming, this is the first time I have 
>> experienced anything like that.
>> I have to say, it was also very cool to experience.
>> 
>> 73,
>> Jack, W6FB
>> 
>>> On Nov 25, 2015, at 11:38 PM, Bill Frantz <frantz at pwpconsult.com> wrote:
>>> 
>>> We had a report at the November West Valley Amateur Radio Association 
>>> meeting of one member who experienced "echos" from his own CW 
>>> transmissions during Sweepstakes on November 7-8. He verified by 
>>> listening to another nearby station that the echo was 1/7 second later, 
>>> the time for a radio signal to go around the world. The K3's full break 
>>> in allowed him to hear himself between the morse code units.
>>> 
>>> 73 Bill AE6JV
>>> 
>>> On 11/26/15 at 10:25 PM, arato.andras at wigner.mta.hu (Andras ARATO) 
>>> wrote:
>>> 
>>>> I could see this these days, but it was my signal coming back from 
>>>> around the Earth when transmitting on 21 MHz. It was a good propagation 
>>>> with K=1 and SFI=121. I could hear it too.
>>>> 
>>>> 73! de HA4AA Andras
>>> 
>>> -----------------------------------------------------------------------
>>> Bill Frantz        | Truth and love must prevail  | Periwinkle
>>> (408)356-8506      | over lies and hate.          | 16345 Englewood Ave
>>> www.pwpconsult.com |               - Vaclav Havel | Los Gatos, CA 95032
>>> 
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