LDEs (Long-Delayed Echos)
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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 <[hidden email]> >To: [hidden email] >Subject: Re: [Elecraft] P3 Showing Transmit Signal >Message-ID: <[hidden email]> >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 <[hidden email]> 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, [hidden email] (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 >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: LDEs (Long-Delayed Echos)
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An 80m or 160m signal echo after about 1/7 second may seem like a round-the-world echo. But it is more likely that it is a ducted signal in the magnetosphere. The actual delay varies with geomagnetic latitude, and the further south one is the closer the delay time is to 1/7 second.
Such signals can be trapped in occasionally occurring, tubular magnetospheric ducts, which stretch from the northern to the southern hemispheres along the Earth's magnetic-field lines. I wrote about it in QST in 2009 - http://folk.uio.no/sverre/papers/2009_MagnetoDucting-QST-LA3ZA.pdf. There was also an excellent article about it in Radcom by P. Martinez (G3PLX), "Long Delayed Echoes, A Study of Magnetospheric Duct Echoes 1997-2007," Radcom, Oct 2007, pp. 60-63 (not on the web to my knowledge). I have an analysis of several such medium delayed echoes or magnetospherically delayed echoes (MDE), including that of G3PLX, here: http://la3za.blogspot.no/2010/03/magnetospherically-ducted-echo.html The echo time can be predicted from latitude, so if I get more data, I can run my program to estimate the delay time for a given place at a certain time (geomagnetic latitude rel to geographic latitude varies with time).
Sverre, LA3ZA
K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html |
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Isn't that the same Peter M that wrote the Dopplergram program? If so,
he is one smart cookie... He is in my Dopplergram group on Yahoo, and the depth of knowledge he demonstrates almost daily is amazing... -- Thanks and 73's, For equipment, and software setups and reviews see: www.nk7z.net For MixW support see; http://groups.yahoo.com/neo/groups/mixw/info For Dopplergram information see: http://groups.yahoo.com/neo/groups/dopplergram/info For MM-SSTV see: http://groups.yahoo.com/neo/groups/MM-SSTV/info On Sat, 2015-11-28 at 03:08 -0700, Sverre Holm (LA3ZA) wrote: > There was also an excellent article about it in Radcom by P. Martinez > (G3PLX), "Long Delayed Echoes, A Study of Magnetospheric Duct Echoes > 1997-2007," Radcom, Oct 2007, pp. 60-63 (not on the web to my knowledge). > > I have an analysis of several such medium delayed echoes or > magnetospherically delayed echoes (MDE), including that of G3PLX, here: > http://la3za.blogspot.no/2010/03/magnetospherically-ducted-echo.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Yes, he's also the originator of the amateur form of AMTOR and PSK31.
73 Stephen On 28 November 2015 at 14:13, David Cole <[hidden email]> wrote: > Isn't that the same Peter M that wrote the Dopplergram program? If so, > he is one smart cookie... He is in my Dopplergram group on Yahoo, and > the depth of knowledge he demonstrates almost daily is amazing... > -- > Thanks and 73's, > For equipment, and software setups and reviews see: > www.nk7z.net > > For MixW support see; > http://groups.yahoo.com/neo/groups/mixw/info > For Dopplergram information see: > http://groups.yahoo.com/neo/groups/dopplergram/info > For MM-SSTV see: > http://groups.yahoo.com/neo/groups/MM-SSTV/info > > > On Sat, 2015-11-28 at 03:08 -0700, Sverre Holm (LA3ZA) wrote: > > > There was also an excellent article about it in Radcom by P. Martinez > > (G3PLX), "Long Delayed Echoes, A Study of Magnetospheric Duct Echoes > > 1997-2007," Radcom, Oct 2007, pp. 60-63 (not on the web to my knowledge). > > > > I have an analysis of several such medium delayed echoes or > > magnetospherically delayed echoes (MDE), including that of G3PLX, here: > > http://la3za.blogspot.no/2010/03/magnetospherically-ducted-echo.html > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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I had no idea he was the originator of AMTOR, and PSK31 as well. That
answers why he know so much... He is in the group for support of Dopplergram, and is very active there... -- Thanks and 73's, For equipment, and software setups and reviews see: www.nk7z.net For MixW support see; http://groups.yahoo.com/neo/groups/mixw/info For Dopplergram information see: http://groups.yahoo.com/neo/groups/dopplergram/info For MM-SSTV see: http://groups.yahoo.com/neo/groups/MM-SSTV/info On Sat, 2015-11-28 at 15:04 +0000, Stephen Prior wrote: > Yes, he's also the originator of the amateur form of AMTOR and PSK31. > > 73 Stephen > > On 28 November 2015 at 14:13, David Cole <[hidden email]> wrote: > > > Isn't that the same Peter M that wrote the Dopplergram program? If so, > > he is one smart cookie... He is in my Dopplergram group on Yahoo, and > > the depth of knowledge he demonstrates almost daily is amazing... > > -- > > Thanks and 73's, > > For equipment, and software setups and reviews see: > > www.nk7z.net > > > > For MixW support see; > > http://groups.yahoo.com/neo/groups/mixw/info > > For Dopplergram information see: > > http://groups.yahoo.com/neo/groups/dopplergram/info > > For MM-SSTV see: > > http://groups.yahoo.com/neo/groups/MM-SSTV/info > > > > > > On Sat, 2015-11-28 at 03:08 -0700, Sverre Holm (LA3ZA) wrote: > > > > > There was also an excellent article about it in Radcom by P. Martinez > > > (G3PLX), "Long Delayed Echoes, A Study of Magnetospheric Duct Echoes > > > 1997-2007," Radcom, Oct 2007, pp. 60-63 (not on the web to my knowledge). > > > > > > I have an analysis of several such medium delayed echoes or > > > magnetospherically delayed echoes (MDE), including that of G3PLX, here: > > > http://la3za.blogspot.no/2010/03/magnetospherically-ducted-echo.html > > > > > > > > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to [hidden email] > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
> Yes, he's also the originator of the amateur form of AMTOR and PSK31. Yes. Peter was the father of AMTOR, one of the most fun modes there ever was, in my opinion. Too bad it died off, especially when today's rigs would handle it so well. The throughput rate was just right to keep you humpin' on the typing and carry on rag chews lasting as long as you didn't run out of material to chew on. ;) By the way, the AMT-1 was his design, if I remember correctly, and built by AEA, who also built the big PK-232. Gary ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: LDEs (Long-Delayed Echos)
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In reply to this post by Stephen G4SJP
"Amtor" existed long before it was a legal mode on
Amateur radio as "SiTOR", (Simplex Teleprinting over Radio" ) on commercial maritime circuits. To my knowledge, there is no basic difference between Sitor and Amtor. Only the name is different. I remember when working for Microlog Corp back in the 70's, when we were developing the SiTor terminal programs, we'd (illegally to be sure) fire up the TR-7 on the marine 12 MHz band and call marine coastal stations to check out our operating program, asking for radio reports etc. We knew most of the ops, so nobody cared too much. Especially if the network was quiet for a while before we called. Curiously, the TR-7 IS fast enough to successfully operate Mode A Amtor. Since there was a several month lead time for ads in QST, I remember getting the inside scoop that the FCC was about to OK the use of both Mode A (hand-shake) and mode B (Forward Error Correction) Sitor, or Amtor if you please on the HAM bands. The ad was scheduled to come out in the issue of QST, the same month the FCC OK came out. This was the "Now, you can chirp back." Ad and boy was I sweating bullets that the OK would in fact come out in time. Luckily for me, it did so I avoided a huge "egg-in-the-face" situation. It was quite a challenge back then to find radios that would switch (from full power transmit to full sensitivity receive) fast enough to run mode A. This was not break-in CW because almost all the programs used AFSK with the rigs in SSB mode. Seems like a century ago...... 73, Charlie k3ICH -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Stephen Prior Sent: Saturday, November 28, 2015 10:04 AM To: Elecraft <[hidden email]> Subject: Re: [Elecraft] LDEs (Long-Delayed Echos) Yes, he's also the originator of the amateur form of AMTOR and PSK31. 73 Stephen ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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That is my recollection as well. SITOR is very much alive and well,
AMTOR, maybe not so much, amateurs tend to move on, sometimes but not always ahead of the pack. :-) NAVTEX is also alive and well, 518 Kcs, I think. Modes I remember but are more or less moribund: AMTOR, HF AX.25 pa, AM. Modes I don't know anything about: Olivia, anything with more than 3 tones, and everything that starts with "JT." 73, Fred K6DGW - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org On 11/28/2015 12:29 PM, Charlie T, K3ICH wrote: > "Amtor" existed long before it was a legal mode on > Amateur radio as "SiTOR", (Simplex Teleprinting > over Radio" ) on commercial maritime circuits. To > my knowledge, there is no basic difference between > Sitor and Amtor. Only the name is different. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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On 11/28/2015 4:44 PM, Fred Jensen wrote:
> That is my recollection as well. SITOR is very much alive and well, > NAVTEX is also alive and well, 518 Kcs, I think. SITOR is the mode of choice for USCG bulletins on HF and their NAVTEX equivalent on 518 kHz. The "official" name for SITOR is NBDP (Narrow Band Direct Printing). San Francisco Marine Radio (Station KSM) transmits press and weather on Saturday afternoons using both RTTY and SITOR My PK-232 decodes SITOR when used in AMTOR mode when I can get a decent signal on their 8 MHz or 12 MHz frequencies. I've given up on NAVTEX (poor antenna). Unfortunately the USCG 8416.5 MHz transmissions fall in the "gap" in K3 coverage. I'm still looking to replace my 35+ year old Kenwood R-5000 Communications Receiver with a more modern one - but no luck so far. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: LDEs (Long-Delayed Echos)
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In reply to this post by Edward A. Dauer
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 <[hidden email]> 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 <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] P3 Showing Transmit Signal >> Message-ID: <[hidden email]> >> 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 <[hidden email]> 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, [hidden email] (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 >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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