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=-2.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,HTML_MESSAGE 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 t0T83Axe029880 for ; Thu, 29 Jan 2015 09:03:10 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1YGjvM-0007b1-MT for rs_out_1@blacksheep.org; Thu, 29 Jan 2015 07:54:00 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1YGjvL-0007as-UN for rsgb_lf_group@blacksheep.org; Thu, 29 Jan 2015 07:53:59 +0000 Received: from rhcavuit01.kulnet.kuleuven.be ([134.58.240.129] helo=cavuit01.kulnet.kuleuven.be) by relay1.thorcom.net with esmtp (Exim 4.85) (envelope-from ) id 1YGjvK-0000oZ-14 for rsgb_lf_group@blacksheep.org; Thu, 29 Jan 2015 07:53:58 +0000 X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-KULeuven-Scanned: Found to be clean X-KULeuven-ID: 6AE551380A2.A3450 X-KULeuven-Information: Katholieke Universiteit Leuven Received: from icts-p-smtps-2.cc.kuleuven.be (icts-p-smtps-2e.kulnet.kuleuven.be [134.58.240.34]) by cavuit01.kulnet.kuleuven.be (Postfix) with ESMTP id 6AE551380A2 for ; Thu, 29 Jan 2015 08:53:52 +0100 (CET) Received: from ICTS-S-HUB4.luna.kuleuven.be (icts-s-hub4.luna.kuleuven.be [10.112.9.18]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by icts-p-smtps-2.cc.kuleuven.be (Postfix) with ESMTPS id 8CDDA200AF for ; Thu, 29 Jan 2015 08:53:46 +0100 (CET) Received: from ICTS-S-MBX1.luna.kuleuven.be ([fe80::edaf:341f:90e:f70e]) by ICTS-S-HUB4.luna.kuleuven.be ([fe80::c11b:83f0:c46c:c366%26]) with mapi id 14.03.0224.002; Thu, 29 Jan 2015 08:53:46 +0100 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Thread-Topic: RL aerial Thread-Index: AQHQO2CWJ3fDpKzUtkW4aOTE3z1bPpzWuGWygAACRpI= Date: Thu, 29 Jan 2015 07:53:45 +0000 Message-ID: <7E7DFBB4D102A04DB5ADC88D66628A4A234BD0E7@ICTS-S-MBX1.luna.kuleuven.be> References: , In-Reply-To: Accept-Language: nl-BE, en-GB, en-US Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mimectl: Produced By Microsoft Exchange V14.3.123.2 x-originating-ip: [10.112.13.13] MIME-Version: 1.0 X-HELO-Warning: Remote host 134.58.240.129 (rhcavuit01.kulnet.kuleuven.be) used invalid HELO/EHLO cavuit01.kulnet.kuleuven.be - verification failed X-Scan-Signature: 9cafc73d135491d75f4f47d39ed43841 Subject: LF: RE: RL aerial Content-Type: multipart/alternative; boundary="_000_7E7DFBB4D102A04DB5ADC88D66628A4A234BD0E7ICTSSMBX1lunaku_" 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 2184 --_000_7E7DFBB4D102A04DB5ADC88D66628A4A234BD0E7ICTSSMBX1lunaku_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Joe, I just simulated the antenna with MMANA-GAL and it resulted in Z =3D 1.57-j= 185.5 Ohm. So the antenna C would be about 1.8 nF. However a 50 uH loading coil point to 2.2 nF antenna capacitance. The extra antenna C may be caused by obstacles close to the antenna (buildi= ngs, trees, ...). If this is the case it will also lower the radiation resistance a bit, so 1= .4 Ohm might be a good guess. 73, Rik ON7YD ________________________________ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org= ] namens jcraig@mun.ca [jcraig@mun.ca] Verzonden: donderdag 29 januari 2015 2:09 Aan: rsgb_lf_group@blacksheep.org Onderwerp: LF: RL aerial Dear Group, Rik and Jean Pierre were asking about the new aerial here. Jean-Pierre sent yesterday a series of captures from 2208-0730 showing much variation in the signal levels on 477.7 kHz. They were quite strong between 0330 and 0500 though there were other peaks and complete fades during the night. Many thanks Jean-Pierre. Here are the details about the "Rotated L" now on the air on 477.7 kHz. Comments and critiques are most welcome. The current was read with a clamp-on ammeter which was then calibrated by measuring current through a 50 ohm load. The wattmeter power was 70 watts but the scope was showing 200V p/p which is 100 watts. Perhaps the wattmeter is reading low. It had a nasty accident with a Decca, was repaired but not properly recalibrated. Assuming the scope is the more accurate, the current was I=3DP/V=3D100/71=3D1.4 A. Scaling the aerial current accordingly yields 1.6 amps. The RL extends from the feedpoint up 27 metres and slopes down to 12 metres over a 100m span. The mean height is about 18 metres. It is fed with ~50 uH of tuning; no R matching was needed. A 30m vertical has Rrad~1 ohm on 630 metres. The ON7YD page gives an expression for Rrad for a horizontal top load, but the RL is sloping this will reduce Rrad. Let's guess that it's 2 ohms So... ERP=3DI^2R=3D 2.6 R or about 5 watts. I'd best crank the variac down a few notches to keep it legal! 73 Joe VO1NA --_000_7E7DFBB4D102A04DB5ADC88D66628A4A234BD0E7ICTSSMBX1lunaku_ Content-Type: text/html; charset="iso-8859-1" Content-ID: <36B90B130CD01B439545254C8BFAA73B@luna.kuleuven.be> Content-Transfer-Encoding: quoted-printable

Hello Joe,

 

I just simulated= the antenna with MMANA-GAL and it resulted in Z =3D 1.57-j185.5 Ohm.

So the antenna C would be about= 1.8 nF.

However a 50 uH<= /a> loading coil point to 2.2 nF antenna capacitance.

The extra antenna C may be caused by obstacles close to the antenna (b= uildings, trees, ...).

If this is the ca= se it will = ;also lower the = ;radiation resistance a bit, so 1.4 Ohm might be a good guess.

 

73, Rik  ON7YD

 

Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens jcraig@mun.ca [jcraig@mun.ca]
Verzonden: donderdag 29 januari 2015 2:09
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: LF: RL aerial

Dear Group,

Rik and Jean Pierre were asking about the new aerial here.
Jean-Pierre sent yesterday a series of c= aptures from 2208-07= 30
showing much va= riation in the signal levels on 477= .7 kHz.
They were quite=  strong between= 0330 and 0500 though there
were other peak= s and complete fades=  during the night. Many thanks Jean-Pie= rre.

Here are the details about the "Rotated L" now on the air on 477.7 kHz.
Comments and critiques are most welcome.

The current was read with a clamp-on ammeter which was then 
calibrated by m= easuring current&nbs= p;through a 50 ohm load. = The
wattmeter power was 70 watts but the scope wa= s showing 200V = p/p 
which is 100 watts.  Perhaps the wattmeter is reading low. 
It had a nasty accid= ent with a Decca, wa= s repaired but&= nbsp;not properly
recalibrated.  Assuming the scope is the more accurate, the current
was I=3DP/V=3D100/71=3D1.4 A.  Scaling t= he aerial current accordingly 
yields 1.6 amps.

The RL extends from= the feedpoint up 27 metres and slopes down to
12 metres over a 100m span. The mean height is about 18 metres.
It is fed = with ~50 uH of tunin= g; no R matchin= g was needed.
A 30m vertical = has Rrad~1 ohm on 63= 0 metres. The ON7YD = page gives 
an expression f= or Rrad for a horizontal top load, = but the RL is 
sloping this wi= ll reduce Rrad.  Let's guess that it's 2 ohms

So... ERP=3DI^2R=3D 2.6 R=   or about= 5 watts.

I'd best crank the variac down a few notches to keep it= legal!

73
Joe VO1NA




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