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Cc: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
From: Roger Lapthorn <rogerlapthorn@gmail.com>
Date: Fri, 19 Nov 2010 22:54:27 +0000
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
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Subject: Re: VLF: Long time transmission on earth antenna
Sender: owner-rsgb_lf_group@blacksheep.org
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Reply-To: rsgb_lf_group@blacksheep.org


18dB loss applies only to the near field (induction) loss I think.

73s
Roger G3XBM

Sent from my iPod Touch 4g

On 19 Nov 2010, at 22:05, Gerhard Hickl <gerhard.hickl@aon.at> wrote:

> Hi Stefan!
> 
> At least at my site, QRM/QRN was pretty low this day and so rather the
> (too) wet soil could be the reason for your weak signal.
> 
> I watched you grabber and when I saw you were "only" 40db oN on your
> DFCW6000 window (4-5km), I had no hope to copy your signal here at
> 594km!
> 
> BTW: Do you think it is true that we can assume 18db Loss for twice the
> distance?
> 
> 73
> OE3GHB
> Gerhard
> 
> 
> Am Freitag, den 19.11.2010, 19:32 +0100 schrieb Stefan Schäfer:
>> Hi Gary, VLF,
>> 
>> OK, nothing received this time, not even by Paul Nicholson. A pity.
>> But it was shown that Micheal Oexner clearly received the signal at
>> 250W in DFCW-600 (before some weeks) so it must have been about 10 dB
>> stronger at 100W and 141 µHz. So there must have been other reasons
>> why there was no reception. Maybe the wet soil is still a disadvantage
>> or the QRM was just to high. 
>> I will not give up on the earth antenna but maybe it makes more sense
>> to try more power and a faster mode in shorter distances first. Maybe
>> i will arrange a RX at my parents QTH in 36 km distance...
>> 
>> Its time to make an new kite experiment. If the wind will be fine, i
>> will do it next weekend. Before i want to arrange a 3rd tap on the
>> coil for 300m @ 8970 Hz. And i am highly interested to drive this
>> antenna on 137 kHz :-)
>> 
>> Thanks to all for taking part at the yesterdays test and building up
>> RX and Grabbers! :-)
>> 
>> 73, Stefan/DK7FC
>> 
>> PS: After the test, the PA, SMPS, netbook, car, antenna and the forest
>> is well up! Batteries were discharged to 9 V ;-) 
>> 
>> 
>> 
>> Am 19.11.2010 16:32, schrieb Gary - G4WGT: 
>>> Hello Stefan, 
>>> 
>>> 
>>> Nothing here up to the sound card crashing about midnight.
>>> 
>>> 
>>> 73
>>> 
>>> 
>>> Gary - G4WGT
>>> 
>>> 
>>> On 19 November 2010 11:03, "Jean-Pierre Méré (F1AFJ)"
>>> <jpm.f1afj@online.fr> wrote:
>>>        Hi Stefan ,
>>> 
>>>        Nothing here ! I listening 20:00 to 07:00 today
>>> 
>>>        73 Jean-Pierre f1afj
>>> 
>>>        Le 19/11/2010 11:50, victor13@online.nl a écrit : 
>>> 
>>>                Not a trace Stefan,sorry,
>>> 
>>>                73
>>>                Victor
>>> 
>>>                -----Oorspronkelijk bericht-----
>>>                Van: owner-rsgb_lf_group@blacksheep.org
>>>                [mailto:owner-rsgb_lf_group@blacksheep.org]Namens
>>>                Stefan Schäfer
>>>                Verzonden: vrijdag 19 november 2010 10:15
>>>                Aan: rsgb_lf_group@blacksheep.org
>>>                CC: Paul; Bernd Grupe
>>>                Onderwerp: Re: VLF: Long time transmission on earth
>>>                antenna
>>> 
>>> 
>>>                Dear VLF,
>>> 
>>>                It seems these batteries are not in best condition.
>>>                The carrier got
>>>                weaker and weaker in the morning and disappeared
>>>                arround 5 UTC.
>>> 
>>>                The SMPS that drives the PA is designed to generate
>>>                its own 15 V supply
>>>                once it started to run. But if the input voltage
>>>                falls below 10V (or 9)
>>>                it shuts down. Seems that this has happend... The
>>>                batteries have>  300
>>>                Ah in sum so it should have been no problem,
>>>                actually...
>>> 
>>>                I assume no one except me has detected anything?
>>> 
>>>                BTW: The starting time was 15:30 UTC so the DFCW
>>>                shift appeared at 23:30 UTC
>>> 
>>>                73, Stefan/DK7FC
>>> 
>>> 
>>> 
>>>                No virus found in this incoming message.
>>>                Checked by AVG - www.avg.com
>>>                Version: 8.5.449 / Virus Database: 271.1.1/3265 -
>>>                Release Date: 11/18/10
>>>                19:34:00
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
> 
> 
>