Return-Path: X-Spam-DCC: paranoid 1356; 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, HTML_50_60,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 tA6ImZI4004119 for ; Fri, 6 Nov 2015 19:48:35 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Zum1J-000318-3q for rs_out_1@blacksheep.org; Fri, 06 Nov 2015 18:45:53 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Zum1I-00030p-Dn for rsgb_lf_group@blacksheep.org; Fri, 06 Nov 2015 18:45:52 +0000 Received: from smtpout1.wanadoo.co.uk ([80.12.242.29] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1Zum09-0000BQ-SD for rsgb_lf_group@blacksheep.org; Fri, 06 Nov 2015 18:45:51 +0000 Received: from AGB ([95.150.81.79]) by mwinf5d11 with ME id eJkR1r0081igrwF03JkRvH; Fri, 06 Nov 2015 19:44:26 +0100 X-ME-Helo: AGB X-ME-Date: Fri, 06 Nov 2015 19:44:26 +0100 X-ME-IP: 95.150.81.79 Message-ID: <8E31BC8EB75546E59F99E35AFAAA0DEE@AGB> From: "Graham" To: References: <1843908200.20151104162925@chriswilson.tv><26CC5FFFDC874EF790AD0A7F69E7606F@AGB> In-Reply-To: Date: Fri, 6 Nov 2015 18:44:25 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Scan-Signature: fd73b8f9df6f2b416d7310bde5bfea2c Subject: Re: LF: Capacitive top hat question Content-Type: multipart/alternative; boundary="----=_NextPart_000_0063_01D118C3.28CB5A80" 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: 4850 This is a multi-part message in MIME format. ------=_NextPart_000_0063_01D118C3.28CB5A80 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Not sure why you talk about wire separation, Verticals properly are quire simple, this is not a pure vertical = and not very simple to evaluate , Your making the assumption, that = the system stops radiating at the point of connection to the loop = ? . The feed is at the corner making a Y and not a T .. hence the = question , =20 At what point dose the transformation take place , radiator to = loading ? G, From: Andy Talbot=20 Sent: Wednesday, November 04, 2015 9:11 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Capacitive top hat question 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. =20 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 =20 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=20 Sent: Wednesday, November 04, 2015 8:00 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Capacitive top hat question A pretty thoroughly top loaded vertical, Heff =3D Hactual=20 '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. --=20 Best regards, Chris mailto:chris@chriswilson.tv ------=_NextPart_000_0063_01D118C3.28CB5A80 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Not sure why you talk about wire separation,
 
Verticals  properly  are  quire = simple, this is=20 not a  pure vertical  and not  very  simple  = to =20 evaluate ,  Your making the  assumption, that the  system = stops=20 radiating  at the  point  of  connection  to = the =20 loop ? .
 
The  feed  is  at the  corner making a  = Y =20 and  not  a  T .. hence the  question =  , =20
 
At  what  point  dose the  transformation  = take  place ,  radiator  to  loading  ?
 
G,

Sent: Wednesday, November 04, 2015 9:11 PM
To: rsgb_lf_group@blacksheep.org= =20
Subject: Re: LF: Capacitive top hat = question

16 US units of length ~ 4.9m, so that means it's a bit = more than=20 half the height of mine.  The top hat is near-enough infinite to = all=20 intents and purposes, so its real height is 4.9m.     =20
My antenna is only 7m high, with much smaller top hat. That amount = of top=20 capacitance will drastically reduce the ground resistance, so all more = than=20 likely all quite an efficient vertical radiator.   If there is = enough=20 buried metal in the ground it could be very good indeed.
so we're probably talking about a similar performance - perhaps an=20 efficiency of -40dB on 137kHz.  That's what mines comes out as,=20 anyway.

Horizontal radiaitors don't when they are close to a reflector. =   And=20 the same good ground system that makes it radiate vertically stops the=20 horizontal bit doing anything.   If the ground were very poor, sand = for=20 instance with littel wire underneath, then perhaps the horizontal part = may=20 generate some ExH, but then efficiency would no doubt be so poor that = teh Hpol=20 contribution would be insignificant.

Not sure why you talk about wire separation, he said they are = strapped so=20 its just a two wire, fat vertical.  Which is exactly what I use - = two=20 paralleled conductors of a twin feed.

Vertical antennas really are quite straightforward to analyse /=20 measure

Andy  G4JNT



On 4 November 2015 at 20:21, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
I dont think its  that  simple Andy ,
 
16 ft is  not  much  for  136 ,  and = the =20 loop  runs  up from  the  feed  point , which = I=20 think  is  a  corner ,, so  at  what =20 point  is  it a radiating  element  and =20 which  point  is it   top  loading  =
 
Ae could look like a sloping  Y  at =20 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
Subject: Re: LF: Capacitive top hat = question

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

'jnt


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

I wonder  what  exactly  is  = radiating=20 Chris ?

what  to  you  estimate the  = beam =20 pattern to  be ,  I have the  idea , south  = to  SV=20 is down , compared to  say  North TF ? , the  = levels =20 into Iceland  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: = Capacitive top hat question

04 November 2015


On my 136khz set up = I have a=20 short piece of ladder line (about 16 feet
high, strapped = together at=20 the base only) feeding the corner of my
horizontal quad loop, = which is=20 about 460 feet in circumference. If I
am TX'ing with WSPR I can = walk=20 around under all of the loop and a
fluorescent tube at waist = height=20 will light quite brightly. Should the
loop also radiate as well = as the=20 vertical section? Sorry for the
probably naive question, I am = not sure=20 whether it's normal or not,
thanks.



-- =


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


=


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