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Date: Sat, 26 Feb 2011 13:23:37 -0800
From: Scott Tilley <sthed475@telus.net>
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Subject: Re: LF: Re: Proposed Eu waterhole center 136.172 kHz
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VE7TIL Grabber QSY @ 0300UTC to center on 136172.0Hz



On 2/26/2011 12:54 PM, rn3agc wrote:
> Hello Markus, LF,
>
> At 23.00z I want to move an Eu-window of my grabber on "new"
> frequencies, with the center 136.172 khz.
>
> If someone is interested in control of the transmitting on "old"=20
> frequencies
> at this night, please inform. I will make display of concrete necessary
> frequency in a small window.
>
> 73
> Andrey
>
>
>
>
> Dear LF,
>
> after some detailed investigation of the interference situation at=20
> W1VD and
> VE7TIL, we propose to move down the recommended Eu TX slot by 5 Hz,=20
> from the
> current center frequency 136177 to 136172 Hz. The latter seems to be=20
> clear
> for Jay within about +-4 Hz (ie 136168 to 136176 Hz). HGA sidebands in
> Europe are no worse as we are still within their spectral gap.
>
> I would ask all interested receive stations to include this range in=20
> their
> observations, and look for possible interference at this QRG. If no=20
> serious
> problem pops up, we could all shift our grabber slots.
>
> Best 73,
> MArkus (DF6NM)
>
>
> -----Urspr=C3=BCngliche Mitteilung----- Von: Markus Vester=20
> <markusvester@aol.com>
> An: rsgb_lf_group@blacksheep.org
> Verschickt: So., 13. Feb. 2011, 21:53
> Thema: Re: New Eu slot 136.177 kHz?
>
>
>
> Dear LF group,
>
> the considerations which led to the choice of a new Eu waterhole have=20
> been
> explained in a posting from Dec 12th, attached beneath. Here's a brief
> summary of the current situation:
>
> - We clearly need separate E-W and W-E slots, due to side effects of=20
> noise
> blanking, and imperfections of transmitters and receivers.
>
> - The Canadian West coast (Scott, Steve) experiences wide-area=20
> interference
> (presumably PLC), centered on 135700 and 136320. This is what=20
> triggered the
> search for an alternative Eu slot.
>
> - Central and Eastern Europe suffers from HGA22 sidebands, except for=20
> a few
> narrow slots (135.975, 136.177, 136.38) . The density of FSK telegrams=
 on
> DCF39 and HGA22 has been increasing.
>
> - We want to stay far enough from 137.0 in case CFH would be fired up=20
> more
> regularly.
>
>
> - But we now have the problem that Jay is affected by local QRM around
> 136.177. It consists.predominantly of a group of unstable lines,=20
> spaced by
> about 1 Hz.
>
> I had secretly hoped that Jay might ultimately find a way to identify an=
d
> fix the problem locally, but this may simply not be feasible. How far=20
> up and
> down does this interference extend in frequency? I'm also not sure=20
> whether
> Warren is actually having the same difficulty or not.
>
>
> Now we have the dilemma that if we stay on the new slot, we may loose=20
> many
> excellent high-quality observations from Jay. If we move back to the old
> one, we give away the slim chance of being picked up by Scott or his=20
> friends
> during that special Transpolar night.
>
> The best choice may be to move on again. If we decide so, we will then=
=20
> need
> to collect information regarding bad and good channels from all key=20
> players,
> perhaps by detailed analysis of wav recordings of the whole lower part=
 of
> the band.
>
> Best regards,
> Markus (DF6NM)
>
>
>
>
>
>
> From: Markus Vester
> Sent: Sunday, December 12, 2010 3:13 PM
> To: rsgb_lf_group@blacksheep.org
> Subject: New Eu slot 136.177 kHz?
>
>
>
> Dear LF,
>
> after considerations with Scott VE7TIL, Mike G3XDV, and Laurence KL7UK,=
 I
> would like to discuss moving the European intercontinental transmit=20
> slot. It
> is currently centered on 136.320 kHz, and I propose a new center=20
> frequency
> of 136.177 kHz.
>
> This discussion was initiated by VE7TIL, who is plagued by severe QRM=20
> lines,
> to an amount that he considers the vicinity of 136.32 kHz as being=20
> unusable
> for him. Scott believes that the interference is caused by a PLC system
> leaking from a nearby powerline, and that it will probably not be=20
> possible
> to fix it locally. Of course it can be disputed whether QRM at one=20
> receive
> site would be reason enough to change a band plan, which has been=20
> useful for
> a number of years. On the other hand, there is only a limited number of
> receivers around the world. And we would certainly like to have Scott
> onboard, as the path from Eu to the American West coast is certainly=20
> one of
> the most challenging ones.
>
> A few years ago, we decided to move Eu transmissions from the original
> 135922 Hz to 136320 Hz, driven by a wider gap in the American Loran-C=20
> line
> spectrum. Since the shutdown of US and Canadian Loran chains, this is no
> longer an issue.
>
> One benefit of going back to a lower frequency would be moving further=
=20
> away
> from the Canadian military transmitter CFH, which occasionally sends=20
> out a
> strong FSK (or MSK) signal centered on 137.0 kHz. It would be=20
> interesting to
> get some information how much this one actually affects the American LF
> background at different frequency offsets.
>
> Here in Europe and Russia, a possible disadvantage of going down is=20
> that we
> would also come closer to HGA22. This is the 100 kW telecontrol=20
> transmitter
> in Budapest, an idle carrier sitting at 135.43 kHz, and excursions to=20
> 135.77
> during FSK bursts. Normally these bursts appear every 11 seconds, but at
> times there are annoying blocks of consecutive telegrams several minutes
> long. Here in Bavaria, the FSK modulation sidebands are visibe up to=20
> about
> 136.5 kHz, but there are pronounced spectral gaps due to the 200 bd
> modulation. These clear gaps are near 135.97, 136.17 and 136.37 kHz.
>
> We looked at 136.37 first, but this would not fix the problem for Scott.
> 135.97 seems worse in Europe due to Luxembourg effect impressed on=20
> HGA, and
> is also getting close to the Greek military SXV. So we decided to=20
> focus on
> 136.17 kHz. A closer look revealed that this very useful FSK minimum is
> actually centered on 136177 Hz, and about 8 Hz wide.
>
> For the last few days, I have been running my grabber
> http://www.alice-dsl.net/df6nm/grabber/Grabber.htm with a split window,
> showing both the present and the proposed new slot side by side. The=20
> direct
> modulation sidebands (showing as red bands) are much better on the new
> frequency. Nighttime Luxembourg QRM generally does not appear to be=20
> worse,
> despite being closer to the HGA carrier. We also expect the latter to=20
> be a
> more regionally confined effect, which will not be present in remote=20
> areas
> of the world. After all, the main purpose of Eu-slot grabbers within=20
> Euroupe
> would not so much be ultimate sensitivity, but rather to provide a=20
> monitor
> for intra-Eu transmit frequency coordination, and a comparison log for
> verification of DX receptions.
>
> Before coming to a possible decision to move the Eu frequency band, we=
=20
> would
> like to collect some feedback on the receive situation in different=20
> parts of
> the world. Traditionally, Eu slot transmissions were primarily targeted
> towards the American east coast. But of course we would like to include
> other areas of the world. How useful would the proposed slot be for=20
> example
> in Russia or Japan?
>
> Active Loran-C rates in Japan are GRI 8930 (lines at 136175.812 and
> 1368181.411 Hz) and GRI 9930 (lines at  136173.212 and 136178.248 Hz).
> Russia uses GRI 8000 with lines at 6.25 Hz multiples, and perhaps GRI=20
> 7950
> (136178.157 Hz). As the frequencies are very accurate, these lines are=
=20
> very
> useful calibration markers.
>
> Now, your opinions please!
>
> Best regards,
> Markus (DF6NM)
>
>
>
>
>