Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=0.3 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE,PLING_QUERY,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u3F9bVQ1022365 for ; Fri, 15 Apr 2016 11:37:31 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ar07P-00087z-0S for rs_out_1@blacksheep.org; Fri, 15 Apr 2016 10:32:51 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ar07O-00087q-L1 for rsgb_lf_group@blacksheep.org; Fri, 15 Apr 2016 10:32:50 +0100 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1ar07M-0006A4-Li for rsgb_lf_group@blacksheep.org; Fri, 15 Apr 2016 10:32:49 +0100 Received: from dovecot03.posteo.de (dovecot03.posteo.de [172.16.0.13]) by mout01.posteo.de (Postfix) with ESMTPS id D1E2F208DD for ; Fri, 15 Apr 2016 11:32:46 +0200 (CEST) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3qmXQ64NRxz5vNF for ; Fri, 15 Apr 2016 11:32:46 +0200 (CEST) Message-ID: <5710B53E.6020507@posteo.de> Date: Fri, 15 Apr 2016 11:32:46 +0200 From: DK7FC User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <57101A93.9050904@posteo.de> <8D364FDC57083E1-13C0-757EEB@webmail-vm186.sysops.aol.com> In-Reply-To: <8D364FDC57083E1-13C0-757EEB@webmail-vm186.sysops.aol.com> X-Scan-Signature: f9f85a03ab18710b130c40acc03380f0 Subject: Re: LF: TXing on VLF again, A fan in series to the antenna?! :-) Content-Type: multipart/alternative; boundary="------------070100030506030807040205" X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7724 This is a multi-part message in MIME format. --------------070100030506030807040205 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Markus, Yes, you're right. I had the wrong value in my mind, downscaled 0.82 Ohm radiation resistance to VLF but that was for a 100m (kite) vertical. So the signal is another 6 dB weaker, maybe 35 uW ERP (not EMRP). 73, Stefan Am 15.04.2016 09:15, schrieb Markus Vester: > Hi Stefan, > I looked for your carrier in the 478 uHz grabber window, but nothing > significant due to the high QRN background. I hope to be able to catch > a daytime transmission as soon as the weather improves. > 150 uW ERP at 0.2 amps (corresponding to Rrad ~ 2 milliohms or heff ~ > 40 meters) sounds a bit optimistic, especially considering surrounding > buildings etc. I think Dex had similar estimated ERP during his > legendary EbNaut TA crossing. > All the best, > Markus > > -----Ursprüngliche Mitteilung----- > Von: DK7FC > An: rsgb_lf_group > Verschickt: Fr, 15 Apr 2016 12:34 am > Betreff: Re: LF: TXing on VLF again, A fan in series to the antenna?! :-) > > > > > VLF, > > BTW the calculated ERP is 150 uW. Quite low :-( But i will be able to > run it permanently... > > The transmission is now stopped and was running from 20:45...22:30 UTC. > > 73, Stefan > > Am 14.04.2016 23:01, schrieb DK7FC: > > Hi VLF, > > > > Since 22:45 i'm running 200 mA on 8270.0050 Hz into my antenna again. > > 200 mA is the limitation of this compact yoghurt-coil. The overall > > system loss is about 1 kOhm, so i just need 40W to run the system at > > 100%. Or, in other words, power is not the limiting factor :-) There > > are holes into the single yoghurt cups so there can be an air flow in > > the cups. And this will be helpful/necessary in summer / daytime. > > 200 mA is about the current consumption of a 12V fan used in PC power > > supplies. So i've constructed a plate with a fan mounted on that, > > improvong the air flow. Later, a tube must be used to form a curve on > > the top of the arrangement to prevent water from flowing between the > > coils. Then, a forced air flow becomes necessary, normal thermal > > convection could be to small. > > https://dl.dropboxusercontent.com/u/19882028/VLF/20160414_214939.jpg > > https://dl.dropboxusercontent.com/u/19882028/VLF/20160414_215835.jpg > > A normal bridge rectifier with UF4007 diodes, then 2 ZD15 Z-diodes, a > > single UF4007 diode (to reduce the voltage a bit) and a 100nF C, > > that's all. It works very well and automatically :-) > > > > 73, Stefan > > > > > > > > Am 13.04.2016 23:28, schrieb Paul Nicholson: > >> > >> Sorry Stefan, nothing showing for 20:14,+30m in > >> 555uHz. The noise floor there is 0.2 fT probably > >> due to all the thunderstorms in Europe tonight. > >> I expect your signal is down below 0.1 fT. > >> > >> Also checked 20:14,+60m in 278 uHz in case you ran > >> for a full hour, but nothing. > >> > >> Let's try again when the background is lower. > >> > >> -- > >> Paul Nicholson > >> -- > >> > > > > > --------------070100030506030807040205 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Markus,

Yes, you're right. I had the wrong value in my mind, downscaled 0.82 Ohm radiation resistance to VLF but that was for a 100m (kite) vertical. So the signal is another 6 dB weaker, maybe 35 uW ERP (not EMRP).

73, Stefan

Am 15.04.2016 09:15, schrieb Markus Vester:
Hi Stefan,
 
I looked for your carrier in the 478 uHz grabber window, but nothing significant due to the high QRN background. I hope to be able to catch a daytime transmission as soon as the weather improves.
 
150 uW ERP at 0.2 amps (corresponding to Rrad ~ 2 milliohms or heff ~ 40 meters) sounds a bit optimistic, especially considering surrounding buildings etc.  I think Dex had similar estimated ERP during his legendary EbNaut TA crossing.
 
All the best,
Markus

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 15 Apr 2016 12:34 am
Betreff: Re: LF: TXing on VLF again, A fan in series to the antenna?! :-)




VLF, 
 
BTW the calculated ERP is 150 uW. Quite low :-( But i will be able to  
run it permanently... 
 
The transmission is now stopped and was running from 20:45...22:30 UTC. 
 
73, Stefan 
 
Am 14.04.2016 23:01, schrieb DK7FC: 
> Hi VLF, 
> 
> Since 22:45 i'm running 200 mA on 8270.0050 Hz into my antenna again.  
> 200 mA is the limitation of this compact yoghurt-coil. The overall  
> system loss is about 1 kOhm, so i just need 40W to run the system at  
> 100%. Or, in other words, power is not the limiting factor :-) There  
> are holes into the single yoghurt cups so there can be an air flow in  
> the cups. And this will be helpful/necessary in summer / daytime. 
> 200 mA is about the current consumption of a 12V fan used in PC power  
> supplies. So i've constructed a plate with a fan mounted on that,  
> improvong the air flow. Later, a tube must be used to form a curve on  
> the top of the arrangement to prevent water from flowing between the  
> coils. Then, a forced air flow becomes necessary, normal thermal  
> convection could be to small. 
> https://dl.dropboxusercontent.com/u/19882028/VLF/20160414_214939.jpg 
> https://dl.dropboxusercontent.com/u/19882028/VLF/20160414_215835.jpg 
> A normal bridge rectifier with UF4007 diodes, then 2 ZD15 Z-diodes, a  
> single UF4007 diode (to reduce the voltage a bit) and a 100nF C,  
> that's all. It works very well and automatically :-) 
> 
> 73, Stefan 
> 
> 
> 
> Am 13.04.2016 23:28, schrieb Paul Nicholson: 
>> 
>> Sorry Stefan, nothing showing for 20:14,+30m in 
>> 555uHz.   The noise floor there is 0.2 fT probably 
>> due to all the thunderstorms in Europe tonight. 
>> I expect your signal is down below 0.1 fT. 
>> 
>> Also checked 20:14,+60m in 278 uHz in case you ran 
>> for a full hour, but nothing. 
>> 
>> Let's try again when the background is lower. 
>> 
>> --  
>> Paul Nicholson 
>> --  
>> 
>


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