Return-Path: Received: from mtain-dd11.r1000.mx.aol.com (mtain-dd11.r1000.mx.aol.com [172.29.64.151]) by air-df06.mail.aol.com (v126.13) with ESMTP id MAILINDF063-5ef84b6e8b1a3e1; Sun, 07 Feb 2010 04:42:50 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dd11.r1000.mx.aol.com (Internet Inbound) with ESMTP id B404038000082; Sun, 7 Feb 2010 04:42:48 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Ne3eB-00019E-6h for rs_out_1@blacksheep.org; Sun, 07 Feb 2010 09:41:43 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Ne3eA-000195-88 for rsgb_lf_group@blacksheep.org; Sun, 07 Feb 2010 09:41:42 +0000 Received: from smtp03.online.nl ([194.134.41.33]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Ne3e7-0007vc-NT for rsgb_lf_group@blacksheep.org; Sun, 07 Feb 2010 09:41:42 +0000 Received: from smtp03.online.nl (localhost [127.0.0.1]) by smtp03.online.nl (Postfix) with ESMTP id ADAB468036 for ; Sun, 7 Feb 2010 10:41:33 +0100 (CET) Received: from pa3fnytrqxpddu (s5593e077.adsl.wanadoo.nl [85.147.224.119]) by smtp03.online.nl (Postfix) with SMTP for ; Sun, 7 Feb 2010 10:41:33 +0100 (CET) From: To: Date: Sun, 7 Feb 2010 10:41:33 +0100 Message-ID: MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 In-Reply-To: <38A51B74B884D74083D7950AD0DD85E82A1AEE@File-Server-HST.hst.e-technik.tu-darmstadt.de> X-MS-TNEF-Correlator: Importance: Normal X-Online-Scanned: by Cloudmark authority (on smtp03.online.nl) X-Spam-Score: 0.8 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276,NO_REAL_NAME=0.55 Subject: LF: RE: RE: active ant on metallic mast Content-Type: multipart/mixed; boundary="----=_NextPart_000_0021_01CAA7E2.1DB180A0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.8 required=5.0 tests=FROM_ENDS_IN_NUMS,HTML_20_30, HTML_FONTCOLOR_BLUE,HTML_MESSAGE,MAILTO_TO_SPAM_ADDR,NO_REAL_NAME 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-VSS-INFO: 5400.1158/54546 X-AOL-VSS-CODE: clean x-aol-sid: 3039ac1d40974b6e8b183e1c X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0021_01CAA7E2.1DB180A0 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0022_01CAA7E2.1DB180A0" ------=_NextPart_001_0022_01CAA7E2.1DB180A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Re: LF: AW: Re: test signal wantedHello Stefan, I will sent you the design directly because it is to big a file for blacksheep.It is a design with just 2 fets and 3 transistors. The shed has ia 230V supply so it isn't isolated.When I increased the= hight both qrm decreased and signals increased,getting higher then 7m didn't improve much.Since I am not allowed to build higher then 5 m above the= roof I left it this way! (the pole and the coax have their own earthing in= the shed,their are also 2 common mode shokes in the coax to the house) For the lenght of the whip 60cm was ideal for this situation,I could= still hear the weakest beacons (var,fny) and their where no signs of im of= the local mw stations.DCF is 500uV (S9+20dB) at this moment,off course on= a calibrated meter. good luck with your experiments, 73 Victor -----Oorspronkelijk bericht----- Van: Stefan Sch=E4fer [mailto:owner-rsgb_lf_group@blacksheep.org]Nam= ens Stefan Sch=E4fer Verzonden: zaterdag 6 februari 2010 23:51 Aan: rsgb_lf_group@blacksheep.org Onderwerp: AW: RE: active ant on metallic mast Hi Victor,=20 Where can i get the design of your preamp? Is it a broad band design= or also with some band pass filters? Is it with FETs and/or with OP amps?= 28V? I assume +-14V, right? ;-) Is in this shed a 230V supply or is it completely ("electrically")= apart from the house? "Less qrm and higher output", does this mean the noise level itself decreased, so not compared to the wanted signal? If hight increases an= d the influence of surrounding lossy things decreases, the E-Field and thus= the input voltage increases, and thus the SNR, if noise level remains the= same. And if you then decrease the AF of your RX to get again a proper visib= le signal in e.g. Argo, the noise gets into the background. But does the noiselevel itself decreases also significantly? If so, there must be= a noise source in the near of the shed, isn't it? I think when i will do the test with the active antenna with the 2= UKW variable antennas, i will mount it to the kite and look how it depends= when it is 50m above ground, completely isolated. Perhaps not very useful= but interesting ;-) You decreased the lenght from 1m to 60cm. Have you also tried 30cm? A hight of 7m gave the best results you said. So things get worse,= when you go to 10m hight?? If so, what do you think is the reason for that?= Or is the shed under a 400kV power line? ;-) Victor and Roelof, tnx for your hints and ideas. I like that convers= ation and i like to try mni unusual things. A receiving loop will give the= best signal i assume, but it is not very easy to handle if one is always /p= .=20 Congrats to the canadian stns to be back on LF!! Hpe to get a contac= t to VO1NA next! But since 6 weeks there is almost no wind at weekend, the longest break since 2 years :-( But i will be back with a big signal= :-) 73, Stefan/DK7FC ----------------------------------------------------------------------= ------ -- Von: owner-rsgb_lf_group@blacksheep.org im Auftrag von victor13@onli= ne.nl Gesendet: Sa 06.02.2010 20:46 An: rsgb_lf_group@blacksheep.org Betreff: LF: RE: active ant on metallic mast Hello Stefan,Roelof, for about 4 years now I am using an active whip with good results.Th= e antenna is placed on a shed about 10 m from the house.I varied the hei= ght between 2 m and 9 m.With a height of 2 m(the roof) I had alot of qrm= and a low output,raising it to 5m or higher improved things a lot.Less qrm= and higher output,to prevent im i decreased the size of the whip from 1m= to 60 cm.At a height of 7m this gives the besr results.no detectable im from= local mw stations and a good S/N ratio of weak signals.As an experiment I re= placed the steel pole for a glassfibre one,this didn't change any thing.This= could be espected because of the coax cable you are always at the same poten= tial as with a steel pole.Ofcourse using a battery and a glassfibre change= s things but for me this is not very practical because my whip draws 120= mA @ 28V. Hope to hear more from your experiments, 73 Victor PA3FNY -----Oorspronkelijk bericht----- Van: Stefan Sch=E4fer [mailto:owner-rsgb_lf_group@blacksheep.org]N= amens Stefan Sch=E4fer Verzonden: zaterdag 6 februari 2010 17:47 Aan: rsgb_lf_group@blacksheep.org Onderwerp: LF: active ant on metallic mast Hi Roelof, LF, Roelof, why do you think that this is the case? Interesting Questi= on! "Won't work" means "Won't work properly" it assume. There will be a si= gnal but perhaps it is not optimal. And why could this be the case? If the application is in a metallic housing that is mounted to a metallic mas= t, the capacity of the "ground electrode" against the environment must be ver= y high (can be seen as infinite, i assume), compared to the active element (g= ate of the FET). Perhaps there will also be a better coupling to qrm sources?= I also have to make some measurements. The antennas we use are comparale= i think. So we could share (all) share our experiences :-) A special question comes up when a optic fiber cable is used, sinc= e in a coax application there remains a high C of the ground electrode, even= when a symmetrical transformer is used (since the active element has just a= few pF to the far field). That special question is: What will happen, when th= e case/ground electrode becomes small against the active element (e.g.= circuit in SMD, small battery inside)?! Will there be a change in the optimal= C of the active element to the far field? I assume, then, one has to define= an optimal C ratio of both electrodes. Will it behave as a short dipole?= And what about a short vertical (30cm) active antenna that is directly pla= ced on the ground with a almost ideal conducting ground plane, e.g. aluminium= foil (out of the household) in a radius of 1m (ignoring the local qrm probl= em, so e.g. in your garden, apart from the city)? On my new qth i made first steps to receive LF with the active ant= enna mounted just 2m above ground but hung up on a wet tree. Results were= vy bad. I thought that SNR could be better when increasing the active element= since signals were weak (DCF39 at S7), but it wasn't. The optimal length was= still 30cm. That seems not only to be "sufficient" but rather optimal! So le= ss and more is worse, unaffected by the hight above gnd? I think one has to imagine the E-Field lines that are going throug= h the ambience. The fieldstrength seems just to be very small in a lossy environment (on my hill, where no trees can be found, the antenna was= also 2m up and DCF39 was S9+20). So hight above ground seems to essencial,= even without local qrm. Each decrease of input signal can be compensated by= more gain but SNR decreases, of course. What are your ideas to these thoughts? What do you think will happ= en if the ground-electrode-C becomes small against the C of the active eleme= nt? What will be the optimum C for both? Will the electrodes have the same "importance", like as a short dipole? Questions over Questions ;-)=20 Recently i had the idea to test that with a variable antenna of a= /p UKW radio, perhaps two for each electrode. That will be interesting to pla= y with ;-) 73!! Stefan/DK7FC ----------------------------------------------------------------------= ------ Von: owner-rsgb_lf_group@blacksheep.org im Auftrag von Roelof Bakk= er Gesendet: Sa 06.02.2010 13:53 An: rsgb_lf_group@blacksheep.org Betreff: Re: LF: AW: Re: test signal wanted Hello Stefan, Probably a bit late, bit I have been told that an active whip won'= t work well on a metalic mast. I never tried it myself (still on the to do list) due to lack of= a=20 suitable mast. 73, Roelof, pa0rdt ------=_NextPart_001_0022_01CAA7E2.1DB180A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Re: LF: AW: Re: test signal wanted</TITLE= > <META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-88= 59-1"> <META content=3D"MSHTML 6.00.6000.16788" name=3DGENERATOR></HEAD> <BODY> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>Hello=20 Stefan,</FONT></SPAN></DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>I will=20 sent you the design directly because it is to big a file for blackshee= p.It is a=20 design with just 2 fets and 3 transistors.</FONT></SPAN></DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>The=20 shed has ia 230V supply so it isn't isolated.When I increased the high= t both qrm=20 decreased and signals increased,getting higher then 7m didn't improve= much.Since=20 I am not allowed to build higher then 5 m above the roof I left it thi= s way!=20 (the pole and the coax have their own earthing in the shed,their are= also 2=20 common mode shokes in the coax to the house)</FONT></SPAN></DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>For=20 the lenght of the whip 60cm was ideal for this situation,I could still= hear the=20 weakest beacons (var,fny) and  their where no signs of im of = ;the local=20 mw stations.DCF is 500uV (S9+20dB) at this moment,off course on a cali= brated=20 meter.</FONT></SPAN></DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>good=20 luck with your experiments,</FONT></SPAN></DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>73</FONT></SPAN></DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D002182609-07022010><FONT face=3DArial color=3D#0000= ff size=3D2>Victor</FONT></SPAN></DIV> <BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px"> <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT face= =3DTahoma size=3D2>-----Oorspronkelijk bericht-----<BR><B>Van:</B>= Stefan Sch=E4fer=20 [mailto:owner-rsgb_lf_group@blacksheep.org]<B>Namens </B>Stefan=20 Sch=E4fer<BR><B>Verzonden:</B> zaterdag 6 februari 2010 23:51<BR><B>= Aan:</B>=20 rsgb_lf_group@blacksheep.org<BR><B>Onderwerp:</B> AW: RE: active ant= on=20 metallic mast<BR><BR></FONT></DIV> <DIV id=3DidOWAReplyText55831 dir=3Dltr> <DIV dir=3Dltr><FONT face=3DArial color=3D#000000 size=3D2>Hi Victor= , </FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>Where can i get the desig= n of your=20 preamp? Is it a broad band design or also with some band pass filter= s? Is it=20 with FETs and/or with OP amps? 28V? I assume +-14V, right? ;-)</FONT= ></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>Is in this shed a 230V su= pply or is it=20 completely ("electrically") apart from the house?</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>"Less qrm and higher outp= ut", does this=20 mean the noise level itself decreased, so not compared to the wanted= signal?=20 If hight increases and the influence of surrounding lossy things dec= reases,=20 the E-Field and thus the input voltage increases, and thus the SNR,= if noise=20 level remains the same. And if you then decrease the AF of your RX= to get=20 again a proper visible signal in e.g. Argo, the noise gets into the= =20 background. But does the noiselevel itself decreases also significan= tly? If=20 so, there must be a noise source in the near of the shed, isn't=20 it?</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>I think when i will do th= e test with the=20 active antenna with the 2 UKW variable antennas, i will mount it to= the kite=20 and look how it depends when it is 50m above ground, completely isol= ated.=20 Perhaps not very useful but interesting ;-)</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>You decreased the lenght= from 1m to 60cm.=20 Have you also tried 30cm?</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>A hight of 7m gave the be= st results you=20 said. So things get worse, when you go to 10m hight?? If so, what do= you think=20 is the reason for that? Or is the shed under a 400kV power line?=20 ;-)</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>Victor and Roelof, tnx fo= r your hints and=20 ideas. I like that conversation and i like to try mni unusual things= . A=20 receiving loop will give the best signal i assume, but it is not ver= y easy to=20 handle if one is always /p. </FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2><STRONG>Congrats to the= canadian stns to=20 be back on LF!!</STRONG> Hpe to get a contact to VO1NA next! But sin= ce 6 weeks=20 there is almost no wind at weekend, the longest break since 2 years&= nbsp;:-(=20 But i will be back with a big signal :-)</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>73, Stefan/DK7FC</FONT></= DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV></DIV> <DIV dir=3Dltr><BR> <HR tabIndex=3D-1> <FONT face=3DTahoma size=3D2><B>Von:</B> owner-rsgb_lf_group@blacksh= eep.org im=20 Auftrag von victor13@online.nl<BR><B>Gesendet:</B> Sa 06.02.2010=20 20:46<BR><B>An:</B> rsgb_lf_group@blacksheep.org<BR><B>Betreff:</B>= LF: RE:=20 active ant on metallic mast<BR></FONT><BR></DIV> <DIV dir=3Dltr> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2>Hello Stefan,Roelof,</FONT></SPAN></DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2>for=20 about 4 years now I am using an active whip with good results.The an= tenna is=20 placed on a shed about 10 m from the house.I varied the height betwe= en 2 m and=20 9 m.With a height of 2 m(the roof) I had alot of qrm and a low outpu= t,raising=20 it to 5m or higher improved things a lot.Less qrm and higher output,= to prevent=20 im i decreased the size of the whip from 1m to 60 cm.At a height of= 7m this=20 gives the besr results.no detectable im from local mw stations and= a good S/N=20 ratio of weak signals.As an experiment I replaced the steel pole for= a=20 glassfibre one,this didn't change any thing.This could be espected= because of=20 the coax cable you are always at the same potential as with a steel= =20 pole.Ofcourse  using a battery and a glassfibre changes things= but for me=20 this is not very practical because my whip draws 120mA @=20 28V.</FONT></SPAN></DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2>Hope=20 to hear more from your experiments,</FONT></SPAN></DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2>73</FONT></SPAN></DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2>Victor</FONT></SPAN></DIV> <DIV><SPAN class=3D314413119-06022010><FONT face=3DArial color=3D#00= 00ff size=3D2>PA3FNY</FONT></SPAN></DIV> <BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px"> <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT fac= e=3DTahoma size=3D2>-----Oorspronkelijk bericht-----<BR><B>Van:<= /B> Stefan Sch=E4fer=20 [mailto:owner-rsgb_lf_group@blacksheep.org]<B>Namens </B>Stefan=20 Sch=E4fer<BR><B>Verzonden:</B> zaterdag 6 februari 2010 17:47<BR><= B>Aan:</B>=20 rsgb_lf_group@blacksheep.org<BR><B>Onderwerp:</B> LF: active ant= on metallic=20 mast<BR><BR></FONT></DIV> <DIV id=3DidOWAReplyText11395 dir=3Dltr> <DIV dir=3Dltr><FONT face=3DArial color=3D#000000 size=3D2>Hi Roel= of,=20 LF,</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>Roelof, why do you thin= k that this is=20 the case? Interesting Question! "Won't work" means "Won't work pro= perly" it=20 assume. There will be a signal but perhaps it is not optimal. And= why could=20 this be the case? If the application is in a metallic housing that= is=20 mounted to a metallic mast, the capacity of the "ground electrode"= against=20 the environment must be very high (can be seen as infinite, i assu= me),=20 compared to the active element (gate of the FET). Perhaps there wi= ll also be=20 a better coupling to qrm sources? I also have to make some measure= ments. The=20 antennas we use are comparale i think. So we could share (all) sha= re our=20 experiences :-)</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>A special question come= s up when a=20 optic fiber cable is used, since in a coax application there remai= ns a high=20 C of the ground electrode, even when a symmetrical transformer is= used=20 (since the active element has just a few pF to the far field). Tha= t special=20 question is: What will happen, when the case/ground electrode = ;becomes=20 small against the active element (e.g. circuit in SMD, small batte= ry=20 inside)?! Will there be a change in the optimal C of the active el= ement to=20 the far field? I assume, then, one has to define an optimal C rati= o of both=20 electrodes. Will it behave as a short dipole? And what about a sho= rt=20 vertical (30cm) active antenna that is directly placed on the grou= nd with a=20 almost ideal conducting ground plane, e.g. aluminium foil (out of= the=20 household) in a radius of 1m (ignoring the local qrm problem, so= e.g. in=20 your garden, apart from the city)?</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>On my new qth i made fi= rst steps to=20 receive LF with the active antenna mounted just 2m above ground bu= t hung up=20 on a wet tree. Results were vy bad. I thought that SNR could be be= tter when=20 increasing the active element since signals were weak (DCF39 at S7= ), but it=20 wasn't. The optimal length was still 30cm. That seems not only to= be=20 "sufficient" but rather optimal! So less and more is worse, unaffe= cted by=20 the hight above gnd?</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>I think one has to imag= ine the E-Field=20 lines that are going through the ambience. The fieldstrength seems= just to=20 be very small in a lossy environment (on my hill, where no trees= can be=20 found, the antenna was also 2m up and DCF39 was S9+20). So hight= above=20 ground seems to essencial, even without local qrm. Each decrease= of input=20 signal can be compensated by more gain but SNR decreases, of=20 course.</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>What are your ideas to= these thoughts?=20 What do you think will happen if the ground-electrode-C becomes sm= all=20 against the C of the active element? What will be the optimum C fo= r both?=20 Will the electrodes have the same "importance", like as a short di= pole?=20 Questions over Questions ;-) </FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>Recently i had the idea= to test that=20 with a variable antenna of a /p UKW radio, perhaps two for each el= ectrode.=20 That will be interesting to play with ;-)</FONT></DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT> </DIV> <DIV dir=3Dltr><FONT face=3DArial size=3D2>73!! Stefan/DK7FC</FONT= ></DIV></DIV> <DIV dir=3Dltr><BR> <HR tabIndex=3D-1> <FONT face=3DTahoma size=3D2><B>Von:</B> owner-rsgb_lf_group@black= sheep.org im=20 Auftrag von Roelof Bakker<BR><B>Gesendet:</B> Sa 06.02.2010=20 13:53<BR><B>An:</B> rsgb_lf_group@blacksheep.org<BR><B>Betreff:</B= > Re: LF:=20 AW: Re: test signal wanted<BR></FONT><BR></DIV> <DIV> <P><FONT size=3D2>Hello Stefan,<BR><BR>Probably a bit late, bit I= have been=20 told that an active whip won't work <BR>well on a metalic mas= t.<BR>I=20 never tried it myself (still on the to do list) due to lack of=20 a <BR>suitable mast.<BR><BR>73,<BR>Roelof,=20 pa0rdt<BR><BR></FONT></P></DIV></BLOCKQUOTE></DIV></BLOCKQUOTE></B= ODY></HTML> ------=_NextPart_001_0022_01CAA7E2.1DB180A0-- ------=_NextPart_000_0021_01CAA7E2.1DB180A0 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="winmail.dat" eJ8+IiEJAQaQCAAEAAAAAAABAAEAAQeQBgAIAAAA5AQAAAAAAADoAAEIgAcAGAAAAElQTS5N aWNyb3NvZnQgTWFpbC5Ob3RlADEIAQ2ABAACAAAAAgACAAEGgAMADgAAANoHAgAHAAoAKQAA AAAAHQEBA5AGAAAEAAAeAAAACwACAAEAAAALACMAAAAAAAMAJgAAAAAACwApAAAAAAADAC4A AAAAAAMANgAAAAAAHgBwAAEAAAAcAAAAYWN0aXZlIGFudCBvbiBtZXRhbGxpYyBtYXN0AAIB cQABAAAAKgAAAAHKpywc8q0oQVufKUO+mD2/SWyux34ABsKKAQAG9ncgAAUwDngAF/Y/IAAA AgEdDAEAAAAYAAAAU01UUDpWSUNUT1IxM0BPTkxJTkUuTkwACwABDgAAAABAAAYOAJ7kp9mn ygECAQoOAQAAABgAAAAAAAAAg8kEfu+9E0ylLT9BsvsxYMKAAAAeAEIQAQAAAFcAAAA8MzhB NTFCNzRCODg0RDc0MDgzRDc5NTBBRDBERDg1RTgyQTFBRUVARmlsZS1TZXJ2ZXItSFNULmhz dC5lLXRlY2huaWsudHUtZGFybXN0YWR0LmRlPgAACwABgAggBgAAAAAAwAAAAAAAAEYAAAAA A4UAAAAAAAADAAOACCAGAAAAAADAAAAAAAAARgAAAAAQhQAAAAAAAAMAB4AIIAYAAAAAAMAA AAAAAABGAAAAAFKFAAB9bgEAHgAJgAggBgAAAAAAwAAAAAAAAEYAAAAAVIUAAAEAAAAEAAAA OS4wAAsADYAIIAYAAAAAAMAAAAAAAABGAAAAAIKFAAABAAAAHgAOgAggBgAAAAAAwAAAAAAA AEYAAAAAg4UAAAEAAAATAAAAMDAyMTgyNjA5LTA3MDIyMDEwAAALADqACCAGAAAAAADAAAAA AAAARgAAAAAOhQAAAAAAAAMAPIAIIAYAAAAAAMAAAAAAAABGAAAAABGFAAAAAAAAAwA9gAgg BgAAAAAAwAAAAAAAAEYAAAAAGIUAAAAAAAALAG+ACCAGAAAAAADAAAAAAAAARgAAAAAGhQAA AAAAAAMAcIAIIAYAAAAAAMAAAAAAAABGAAAAAAGFAAAAAAAAAgH4DwEAAAAQAAAAg8kEfu+9 E0ylLT9BsvsxYAIB+g8BAAAAEAAAAIPJBH7vvRNMpS0/QbL7MWACAfsPAQAAAJgAAAAAAAAA OKG7EAXlEBqhuwgAKypWwgAAUFNUUFJYLkRMTAAAAAAAAAAATklUQfm/uAEAqgA32W4AAABE OlxEb2N1bWVudHMgYW5kIFNldHRpbmdzXFZpY3RvclxMb2NhbCBTZXR0aW5nc1xBcHBsaWNh dGlvbiBEYXRhXE1pY3Jvc29mdFxPdXRsb29rXG91dGxvb2sucHN0AAMA/g8FAAAAAwANNP03 AAACAX8AAQAAADIAAAA8QkRFTUtGQ05MTUlJTEdJRk5PTk5DRUlHREhBQS52aWN0b3IxM0Bv bmxpbmUubmw+AAAArMQ= ------=_NextPart_000_0021_01CAA7E2.1DB180A0--