Return-Path: X-Spam-DCC: paranoid 1170; 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=-1.9 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,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 tA4LFmhZ028811 for ; Wed, 4 Nov 2015 22:15:49 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Zu5M5-00066z-EF for rs_out_1@blacksheep.org; Wed, 04 Nov 2015 21:12:29 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Zu5M5-00066q-1k for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2015 21:12:29 +0000 Received: from mail-wi0-f180.google.com ([209.85.212.180]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1Zu5L2-0001XI-VP for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2015 21:12:27 +0000 Received: by wicfv8 with SMTP id fv8so40419025wic.0 for ; Wed, 04 Nov 2015 13:11:09 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=twoekw6HdIoArlVhJU8ZYLUS9f5if7jVvW+E4SXJrq4=; b=fNjpJa0CRMLrBtJeSSkgjwFAabNBANmD4WDPZ9s7oVifruTnnU8c3zyU2RUR0/57FS 4+lTXxjb8WUVTZ4cOlSEtiDDpF7OvKYlRKpXPOcNn6VfzljuW20DW9iIwOlEWLJiNVne iXbkwiqLwnFsyovXrThLpGXJ1m0lH47IA5nMubAqZg8qL4GTlaKeeqTf3jDeyPpw07uH ztZhigCAVy66H71Ye+SAfoehFjQxSic38oixs29b/B/MUbNHVEdOARX089jSQYiQkMuJ xPyWHBiVMF2+jPVJaGFKBZIYR3xZbAajjqZ+usvAa/R1nG1zgLdorHVkbYoQtSqBx9WM 064A== MIME-Version: 1.0 X-Received: by 10.194.87.230 with SMTP id bb6mr4129408wjb.157.1446671469412; Wed, 04 Nov 2015 13:11:09 -0800 (PST) Received: by 10.28.183.139 with HTTP; Wed, 4 Nov 2015 13:11:09 -0800 (PST) In-Reply-To: <26CC5FFFDC874EF790AD0A7F69E7606F@AGB> References: <1843908200.20151104162925@chriswilson.tv> <26CC5FFFDC874EF790AD0A7F69E7606F@AGB> Date: Wed, 4 Nov 2015 21:11:09 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: 081739af09bdcbecda01e4d970c01b31 Subject: Re: LF: Capacitive top hat question Content-Type: multipart/alternative; boundary=047d7bfe95420ab6ce0523bd735c 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: 4823 --047d7bfe95420ab6ce0523bd735c Content-Type: text/plain; charset=UTF-8 16 US units of length ~ 4.9m, so that means it's a bit more than half the height of mine. The top hat is near-enough infinite to all intents and purposes, so its real height is 4.9m. My antenna is only 7m high, with much smaller top hat. That amount of top capacitance will drastically reduce the ground resistance, so all more than likely all quite an efficient vertical radiator. If there is enough buried metal in the ground it could be very good indeed. so we're probably talking about a similar performance - perhaps an efficiency of -40dB on 137kHz. That's what mines comes out as, anyway. Horizontal radiaitors don't when they are close to a reflector. And the same good ground system that makes it radiate vertically stops the horizontal bit doing anything. If the ground were very poor, sand for instance with littel wire underneath, then perhaps the horizontal part may generate some ExH, but then efficiency would no doubt be so poor that teh Hpol contribution would be insignificant. Not sure why you talk about wire separation, he said they are strapped so its just a two wire, fat vertical. Which is exactly what I use - two paralleled conductors of a twin feed. Vertical antennas really are quite straightforward to analyse / measure Andy G4JNT On 4 November 2015 at 20:21, Graham wrote: > I dont think its that simple Andy , > > 16 ft is not much for 136 , and the loop runs up from the feed > point , which I think is a corner ,, so at what point is it a > radiating element and which point is it top loading > > Ae could look like a sloping * Y *at some point , the wire > separation must be too much to act as one ? > > *G,* > > > > *From:* Andy Talbot > *Sent:* Wednesday, November 04, 2015 8:00 PM > *To:* rsgb_lf_group@blacksheep.org > *Subject:* Re: LF: Capacitive top hat question > > A pretty thoroughly top loaded vertical, Heff = Hactual > > 'jnt > > > On 4 November 2015 at 19:50, Graham wrote: > >> (about 16 fee thigh, strapped together at the base only) >> >> I wonder what exactly is radiating Chris ? >> >> what to you estimate the beam pattern to be , I have the idea , >> south to SV is down , compared to say North TF ? , the levels into >> Iceland are significant .. >> >> 73-Graham >> >> >> >> -------------------------------------------------- >> From: "Chris Wilson" >> Sent: Wednesday, November 04, 2015 4:29 PM >> To: >> Subject: LF: Capacitive top hat question >> >> 04 November 2015 >>> >>> >>> On my 136khz set up I have a short piece of ladder line (about 16 feet >>> high, strapped together at the base only) feeding the corner of my >>> horizontal quad loop, which is about 460 feet in circumference. If I >>> am TX'ing with WSPR I can walk around under all of the loop and a >>> fluorescent tube at waist height will light quite brightly. Should the >>> loop also radiate as well as the vertical section? Sorry for the >>> probably naive question, I am not sure whether it's normal or not, >>> thanks. >>> >>> >>> >>> -- >>> >>> >>> Best regards, >>> Chris mailto:chris@chriswilson.tv >>> >>> >>> >> > --047d7bfe95420ab6ce0523bd735c Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
16 US units of length ~ 4.9m, so that means it's a bit= more than half the height of mine.=C2=A0 The top hat is near-enough infini= te to all intents and purposes, so its real height is 4.9m. =C2=A0 =C2=A0= =C2=A0
My antenna is only 7m high, with much smaller top hat. That amou= nt of top capacitance will drastically reduce the ground resistance, so all= more than likely all quite an efficient vertical radiator. =C2=A0 If there= is enough buried metal in the ground it could be very good indeed.
so we're probably talking about a similar performance - perhaps an e= fficiency of -40dB on 137kHz.=C2=A0 That's what mines comes out as, any= way.

Horizontal radiaitors don't when they= are close to a reflector. =C2=A0 And the same good ground system that make= s it radiate vertically stops the horizontal bit doing anything. =C2=A0 If = the ground were very poor, sand for instance with littel wire underneath, t= hen perhaps the horizontal part may generate some ExH, but then efficiency = would no doubt be so poor that teh Hpol contribution would be insignificant= .

Not sure why you talk about wire separation, he = said they are strapped so its just a two wire, fat vertical.=C2=A0 Which is= exactly what I use - two paralleled conductors of a twin feed.
<= br>
Vertical antennas really are quite straightforward to analyse= / measure

Andy =C2=A0G4JNT



On 4= November 2015 at 20:21, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
I dont think its=C2=A0 that=C2=A0 simple Andy ,
=C2=A0
16 ft is=C2=A0 not=C2=A0 much=C2=A0 for=C2=A0 136 ,=C2=A0 and the=C2= =A0=20 loop=C2=A0 runs=C2=A0 up from=C2=A0 the=C2=A0 feed=C2=A0 point , which I=20 think=C2=A0 is=C2=A0 a=C2=A0 corner ,, so=C2=A0 at=C2=A0 what=C2=A0 point= =C2=A0=20 is=C2=A0 it a radiating=C2=A0 element=C2=A0 and=C2=A0=20 which=C2=A0=C2=A0point=C2=A0 is it =C2=A0 top=C2=A0 loading=C2=A0
=C2=A0
Ae could look like a=C2=A0sloping =C2=A0Y=C2= =A0=C2=A0at=C2=A0=20 some=C2=A0 point , the=C2=A0 wire=C2=A0 separation=C2=A0 must be=C2=A0 too= =C2=A0=20 much to=C2=A0 act=C2=A0 as=C2=A0 one=C2=A0 ?
=C2=A0
G,
=C2=A0
=C2=A0

A pretty thoroughly top loaded vertical, Heff =3D Hactual= =20

'jnt


On 4 November 2015 at 19:50, Graham <g8fz= k@g8fzk.fsnet.co.uk> wrote:
(about 16 fee thigh, strapped togethe= r at the base=20 only)

I wonder=C2=A0 what=C2=A0 exactly=C2=A0 is=C2=A0 radiating C= hris=20 ?

what=C2=A0 to=C2=A0 you=C2=A0 estimate the=C2=A0 beam=C2=A0 patt= ern=20 to=C2=A0 be ,=C2=A0 I have the=C2=A0 idea , south=C2=A0 to=C2=A0 SV is do= wn ,=20 compared to=C2=A0 say=C2=A0 North TF ? , the=C2=A0 levels=C2=A0 into=20 Iceland=C2=A0 are significant=20 ..

73-Graham



--------------------------------------= ------------
From:=20 "Chris Wilson" <chris@chriswilson.tv>
Sent: Wednesday, November 04,= =20 2015 4:29 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: LF: Capac= itive=20 top hat question

04 November 2015


On my 1= 36khz set up I have a=20 short piece of ladder line (about 16 feet
high, strapped together at= the=20 base only) feeding the corner of my
horizontal quad loop, which is a= bout=20 460 feet in circumference. If I
am TX'ing with WSPR I can walk a= round=20 under all of the loop and a
fluorescent tube at waist height will li= ght=20 quite brightly. Should the
loop also radiate as well as the vertical= =20 section? Sorry for the
probably naive question, I am not sure whethe= r=20 it's normal or not,
thanks.



--


Best= regards,
Chris=C2=A0 =C2=A0 =C2=A0=20 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0=20 mailto:chris@= chriswilson.tv



<= /div>

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