Return-Path: Received: from mtain-dj05.r1000.mx.aol.com (mtain-dj05.r1000.mail.aol.com [172.19.187.141]) by air-me06.mail.aol.com (v127_r1.1) with ESMTP id MAILINME061-8bb44b8d8a4039a; Tue, 02 Mar 2010 16:59:28 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dj05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 2565138000248; Tue, 2 Mar 2010 16:59:27 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Nma6j-0004es-WB for rs_out_1@blacksheep.org; Tue, 02 Mar 2010 21:58:25 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Nma6j-0004ej-A0 for rsgb_lf_group@blacksheep.org; Tue, 02 Mar 2010 21:58:25 +0000 Received: from mail.gmx.net ([213.165.64.20]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1Nma6g-0001wd-HK for rsgb_lf_group@blacksheep.org; Tue, 02 Mar 2010 21:58:25 +0000 Received: (qmail invoked by alias); 02 Mar 2010 21:58:11 -0000 Received: from p5DD35934.dip.t-dialin.net (EHLO Clemens04) [93.211.89.52] by mail.gmx.net (mp035) with SMTP; 02 Mar 2010 22:58:11 +0100 X-Authenticated: #17214767 X-Provags-ID: V01U2FsdGVkX18Mr94DriQM3wWeaL8zzfj7k88+MUtGfjQ0FxyRz/ sRocwffszaxGww Message-ID: <00da01caba53$738e06a0$0201a8c0@Clemens04> From: "Clemens Paul" To: References: <38A51B74B884D74083D7950AD0DD85E82A1B2A@File-Server-HST.hst.e-technik.tu-darmstadt.de> Date: Tue, 2 Mar 2010 22:58:05 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3598 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 X-Y-GMX-Trusted: 0 X-FuHaFi: 0.44 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: VLF TX experiments_short report Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 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-aol-global-disposition: G x-aol-sid: 3039cdbc9d0a4b8d8a3f0354 X-AOL-IP: 193.82.116.20 Content-Transfer-Encoding: quoted-printable Hi Stefan, >...But thus the internal C is high, so stray currents occur that incr= ease the resistive=20 >losses. Additionally the >proximity effect plays its role... Do you mean circulating currents by 'stray currents' ? Did you measure the self resonant frequency of your coil? As long as you operate at half its self resonant frequency stray capac= itance won't hurt regarding losses. >Q is low, just abt 38 and thus i get such a low voltage at a given po= wer. But i will build a=20 >own VLF coil soon, >with the needed L so that no parallel C will be= required. Doubling a given inductance by a parallel C will quadruple losses at= the same frequency. 73 Clemens DL4RAJ ----- Original Message -----=20 From: "Stefan Sch=E4fer" To: Sent: Tuesday, March 02, 2010 9:09 PM Subject: AW: LF: VLF TX experiments_short report Hi Alexander, LF, Yes, i assumed the Q of the coil to be very high due to the big wire= that is used in it. But=20 thus the internal C is high, so stray currents occur that increase the= resistive losses.=20 Additionally the proximity effect plays its role... Q is low, just abt 38 and thus i get such a low voltage at a given pow= er. But i will build a=20 own VLF coil soon, with the needed L so that no parallel C will be req= uired. This may take=20 some days ;-) The PA gives 130W at 13V now. I will increase the power soon. Yesterday the wind was suitable and the sun was out :-) So i was on th= e hill and did the first=20 test. I even had an oscilloscope there to measure the antenna voltage= and current waveforms.=20 Some photos of the arrangement will be shown on my site at qrz.com in= some days (sri, have=20 forgotten cable between camera and PC...) I just had 1,6kVrms on the wire. That is 23dB less than calculated but= it was a first test.=20 So, the ERP was just 1/200. Additionally i have forgotten a part of th= e ground radial wich=20 increased the earth resistance. Bernd/DF8ZR received in a distance of= abt 16km but got=20 nothing. But i am not sure if his RX equipment was really suitable. Ha= said he wants to=20 improve it. He also said that he can receive the Alpha station but as= we know from LF: You can=20 excellent receive DCF39 but get not even the strongest amateur stn if= your RX is not=20 optimised... I received my own TX signal the the soundcard. Signal was 40dB above= noise even without=20 connecting anything to the input and with the PC shielded by the car= housing. That says=20 nothing, i know. Just that there seems to be a high E-Field in the nea= r or a coupling by the=20 voltage supply... Anyway, i saw that the signal was clean/stable and= "exactly" on the=20 frequency. Trying to receive the 5th harmonic at 45kHz showed no recep= tion in my IC706=20 (starting at 30kHz :-( ) with a wire connected and the waveform looked= perfectly on the=20 scope... In the next test it may be very useful to have some partable or mobile= RX stations in the=20 region. Markus/DF6NM, what do you think about visiting me there, or Ma= rco/DD7PC? We could talk=20 and laugh and eat and drink and test and improve and measure. If we wi= ll be not successful we=20 could talk and drink ;-) That would definitely be the best method to try what is possible with= a given ERP on a given=20 frequency... It may need some time for the next test but i hope we can keep this VL= F fire burning;-) If=20 Paul receives a signal that is generated by the soundcard, so with som= e mW, in 180m, then my=20 optimism is even increasing. But we always have to be careful with the= interpretation of the=20 results and have to ask if it possible that a galvanic/inductive coupl= ing occured, so no=20 radiation (e.g. by the power supply cable. Just like the PC QRM can be= fed into a sensitive=20 active E-Field antenna by a galvanic/inductive/capacitive coupling!).= So, if the signal in=20 this example was generated by a battery fed notebook that stood on a= wooden chair in the=20 garden: congrats!! :-) 73 es GL! Stefan/DK7FC ...now searching for a plastic tube with 40...60mm diameter and 1,2m= length on a building lot=20 ;-) Any better ideas? ________________________________ Von: owner-rsgb_lf_group@blacksheep.org im Auftrag von Alexander S. Yu= rkov Gesendet: Di 02.03.2010 19:40 An: rsgb_lf_group@blacksheep.org Betreff: Re: LF: VLF TX experiments_short report On Mon, 1 Mar 2010, [iso-8859-1] Stefan Sch?fer wrote: > > What i wanted to use as the PA is a prototype of a SMPS that was des= igned to operate at abt=20 > 50kHz. At 9kHz the ferrite core was already driven in saturation. By= varying the driving f i=20 > found, where the saturation occurs. Then i have known how many prima= ry turns i have to spend=20 > at 9kHz. After applying the new windings everything was right. But= the time i had was gone=20 > and the wind was already to strong. So i told Markus to inform you..= . > > Now playing/increasing with the number of output windings of the SMP= S > transformer i applied the output voltage by a ordinary loudspeaker= cable > to the primary air coil that is inductive coupled to the HV coil. I= got > 1,6kV rms by applying 60W at the 12V DC input, really not much :-(= But > anyway it will be suitable for a first test if a apply 6dB more powe= r or > so. Dear Stefan 3.2 kV (6 dB of 1.6 kV) is too low voltage. Expectations= was 20 kV before. Is it any typo? Regards, Alexander ----------------------------------------------------------------------= ---------- Eingehende eMail ist virenfrei. Von AVG =FCberpr=FCft - www.avg.de Version: 9.0.733 / Virendatenbank: 271.1.1/2718 - Ausgabedatum: 03/02/= 10 08:34:00