Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w6VCBpST021208 for ; Tue, 31 Jul 2018 14:11:54 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1fkTQV-0003R2-1y for rs_out_1@blacksheep.org; Tue, 31 Jul 2018 13:06:55 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1fkTQU-0003Qt-Ca for rsgb_lf_group@blacksheep.org; Tue, 31 Jul 2018 13:06:54 +0100 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1fkTQS-0005iz-NJ for rsgb_lf_group@blacksheep.org; Tue, 31 Jul 2018 13:06:53 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id A102021043 for ; Tue, 31 Jul 2018 14:06:50 +0200 (CEST) X-DKIM-Result: Domain=posteo.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.de; s=2017; t=1533038810; bh=LnWGLjE6r2+/KoFvjDwgMfmIyirLX+BA/h7xQcJvSag=; h=Date:From:To:Subject:From; b=iN91MBESvNufPe9KjxqF5RXin3zkNlDVP+qpNMjViEoBRJpsFqffs1MWRx2E0G8sR MlmTNA+CCAzmvb79RnzZ280JQ/t6hVHrVcCVJgh8XlZ5htYvbD0CmIeVytF2Kul7U5 zadxOCvPOGQ9e08nNnuHc8U4/0+TzJUFieizSrC2bCMCwZ8UbtepyvNm/ldaKSGJ8h Zv4Vg2dVy7yuf+k7C/DyzTTtmOCkBMpxn9LQMPbrHMu2gC8fTlsR3C3h+erGJVDMJw 8dN+NeizQYde5NZU2eISrf+zsqCAsgzT5nQEAN1ZjRY5MsPNN6GfP9ERU+Vv/Ev2FA engY30Tun89LA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 41fwCZ24hNz9rxG for ; Tue, 31 Jul 2018 14:06:50 +0200 (CEST) Message-ID: <5B6050DA.60905@posteo.de> Date: Tue, 31 Jul 2018 14:06:50 +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: <5B54CCCB.6060903@posteo.de> <5B59E687.5030805@posteo.de> <5B5C3ABF.3030809@posteo.de> <5B5C4A63.3040504@posteo.de> <5B5C5446.30105@posteo.de> <14080281532786049@iva8-6be7d23653d9.qloud-c.yandex.net> <5B5CD03F.40602@posteo.de> <14811811532865577@myt4-415a3339794b.qloud-c.yandex.net> <5B5DC8BC.9030601@posteo.de> <5B5E2D7D.6050908@posteo.de> <5B5F678B.7000506@posteo.de> <6dc15e3e-a325-4be2-55e3-44413e814f8a@web.de> In-Reply-To: <6dc15e3e-a325-4be2-55e3-44413e814f8a@web.de> X-Spam-Score: -2.0 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Hello Eike, Thanks for your ideas. That Alu-wire is good for normal E-field antennas carrying some kV. A good source, thanks! BUT, here i need an isolated wire because it is laying on the ground directly. OK, one could say that the wire would have only a very bad contact to the ground, anyway when laying on dry grass. But over a length of 900 m i expect the losses will be significant. It could be worth a test to compare both solutions but the isolated cable will work for sure. My wire is already ordered and payed anyway ( https://www.pollin.de/p/lautsprecherkabel-2x0-75-mm2-100m-transparent-cca-562602 ) [...] Content analysis details: (-2.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [185.67.36.66 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.3 PLING_QUERY Subject has exclamation mark and question mark 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: d63ea50e288c5ecb9bd7a86eeabe94f2 Subject: Re: VLF: Earth antenna transmissions on a guide rail?!?? 2nd day... Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.2 required=5.0 tests=PLING_QUERY 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 Hello Eike, Thanks for your ideas. That Alu-wire is good for normal E-field antennas carrying some kV. A good source, thanks! BUT, here i need an isolated wire because it is laying on the ground directly. OK, one could say that the wire would have only a very bad contact to the ground, anyway when laying on dry grass. But over a length of 900 m i expect the losses will be significant. It could be worth a test to compare both solutions but the isolated cable will work for sure. My wire is already ordered and payed anyway ( https://www.pollin.de/p/lautsprecherkabel-2x0-75-mm2-100m-transparent-cca-562602 ) 73, Stefan Am 31.07.2018 13:19, schrieb Eike DL3IKE: > Hi Stefan, > > instead of expensive and heavy copper-wire take a look at this > fence-wire: > https://www.weidezaun.info/voss-farming-aludraht-alu-draht-400-m-2-0-mm.html# > > 400m of 2mm diameter aluminium wire for aprox 30eur has a dc > resistance of 4 Ohm an a weight of only 3,5kg. > You´ll find also other usefull things like these: > https://www.weidezaun.info/weidezaun/verbinder-spanner.html and more > for buildig long antennas. > A lot of those things are sold much mor expensive on ham-radio-markets... > > 73 de Eike DL3IKE > > > > > Am 30.07.2018 um 21:31 schrieb DK7FC: >> Hi VLF and ULF friends, >> >> In the attachment you can find 3 spectrograms from transmission of >> the last weekend. For the 8270 Hz and 2970 Hz transmission i took the >> data of the 900m ground loop, 5170 Hz is from the 450m ground loop. >> The 8270 Hz signal was very strong even in 3.8 mHz ('DFCW-600'). Some >> real QRSS-60 would have been possible! >> The spectrograms also show that there was no trace on the frequency >> of interest before and after the transmission (no traces from the >> right channel ( 1 PPS) ). >> >> A few minutes ago i built the switchable network for resonating the >> antenna properly. And i actually ordered 1000 m of that 0.75 mm^2 >> loudspeaker cable. Thus, in the next experiment i think the Q of the >> antenna will be much higher and it will be possible to tune it >> accurately. Then, the tuning capacitance will tell us what the ground >> loop inductance is! And then, we can calculate the depth where the >> current is flowing backwards in the ground, asuming a simple model in >> first steps. >> Next, we can see whether the inductance or depth stays constant at >> lower frequencies (hopefully it will increase!) by resonating the >> antenna at 2.97 kHz for example. >> >> BTW i measured the DC resistance of the wire i used last weekend, it >> is 116 Ohm, so it agrees well with the calculated 120 Ohm... >> The new wire should have 21.4 Ohm only. >> >> The big advantage of this antenna is that no high voltage and large >> coils are needed. Usually the voltage is the limiting factor for a >> VLF or ULF TX antenna. But not here. Here it is the power of the PA. >> The antenna could easily handle 2 kW, which means 5.16 A, no problem >> for the wire. And it would be a 20 dB stronger signal than last >> weekend... >> >> 73, Stefan >> >> >> >> Am 29.07.2018 23:11, schrieb DK7FC: >>> As a next result from today's experiment, here is a spectrum peak of >>> the 2970.005 Hz transmission. I reached 20 dB SNR in 180 uHz! This >>> far more than expected, in July anyway. >>> It is the first ULF transmission (by amateurs) from an earth >>> electrode TX antenna, detected in the far field. >>> Spectrograms will be produced soon... >>> >>> 73, Stefan >>> >>> >>> Am 29.07.2018 16:01, schrieb DK7FC: >>>> Hello Roman, VLF, >>>> >>>> I transmitted pure carriers each time. It was just a first test. >>>> >>>> Today i've done a second experiment, this time using a 900m long >>>> wire! So the wire should have about 125 Ohm DC resistance. I >>>> measured 220 mA DC at 38.4 V, so the overall loss is 175 Ohm. Very >>>> interesting; the ground loss resistance stays at 50 Ohm although >>>> the distance between the electrodes has doubled! >>>> If i would use the 0.75 mm loudspeaker cable then i can reduce the >>>> losses by 100 Ohm which is more than 50 %, so i will gain 3 dB at >>>> the same output power! Then with a switch mode PA having nearly >>>> 100% efficiency i may gain 2 dB more (mmy lonear mode PA was not >>>> well matched today and quite warm). So maybe i can reach 1 A >>>> antenna current with just 75 watts??!!! >>>> Today i tuned to 550 mA antenna current again, at 8270 Hz. With the >>>> scope, i measured the phas, it was more inductive than yesterday. I >>>> actually found a 1 uF MKP-10 cap in my car and switched it in >>>> series to the antenna. This improved the phase slightly. Then i >>>> also found a low pass filter for 137 kHz, the pypical pi >>>> configuration, i.e. it acts as 4*22 nF in parallel here on this >>>> frequency. Switching this in series leads to a low current, so the >>>> C is to small. So for the next experiment i'm preraring a >>>> switchable C network (47n, 100n, 220n, 470n, 1u, 2.2u, 4.7u). It >>>> will be even more necessary when i lower the wire resistance >>>> (higher Q). >>>> Well, today the QRN was much lower, especially for the 2970.005 Hz >>>> transmission period. Yesterday this was totally buried in the noise >>>> on my RX on the tree. But today! I transmitted another 90 minutes >>>> with much lower QRN background. I already have a clear spectrum >>>> peak but i like to try to improve it a bit more before presenting >>>> it here. >>>> Todays carrier transmissions: >>>> 8270.000 Hz : 08:12...09:33 UTC >>>> 2970.005 Hz : 09:42...11:15 UTC >>>> >>>> Sorry for the confusing email ;-) >>>> >>>> 73, Stefan > > >