[600MRG] For discussion: Re: Top loading a vertical on LF/MF

Thu Nov 28 10:20:48 CST 2013

Some AM broadcast antennas have top loading... it has been shown to work best when the loading wires are closer to horizontal.   I recall experiments with drooping the loading wires to try and control the vertical radiation pattern and reduce the signal at certain skywave takeoff angles, so that supports the idea mentioned that lowering the wires could cause cancellation for at least some angles.

I'll try and find some references...

Steve WD8DAS

sbjohnston at aol.com
http://www.wd8das.net/
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-----Original Message-----
From: 600mrg-request <600mrg-request at w7ekb.com>
To: 600mrg <600mrg at w7ekb.com>
Sent: Wed, Nov 27, 2013 10:16 pm
Subject: 600MRG Digest, Vol 31, Issue 41

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Today's Topics:

   1. Re: For discussion: Re: Top loading a vertical on LF/MF
      (Eric NO3M)
   2. Re: For discussion: Re: Top loading a vertical on LF/MF
      (jrusgrove at comcast.net)
   3. Re: For discussion: Re: Top loading a vertical on LF/MF
      (Pat Hamel)
   4. Neil -  Vertical top loading (Ken Roberson)
   5. /20 (Rudy Severns)
   6. Re: /20 (Ralph Hartwell)
   7. Re: /20 (Mike-WE0H)

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Message: 1
Date: Wed, 27 Nov 2013 19:02:17 -0500
From: Eric NO3M <no3m at no3m.net>
To: 600mrg at w7ekb.com
Subject: Re: [600MRG] For discussion: Re: Top loading a vertical on
	LF/MF
Message-ID: <52968809.5060804 at no3m.net>
Content-Type: text/plain; charset=windows-1252; format=flowed

Err, increase gain in a certain direction.....

On 11/27/2013 06:58 PM, Eric NO3M wrote:
> increase ERP concentrated in a certain direction

------------------------------

Message: 2
Date: Wed, 27 Nov 2013 19:22:52 -0500
From: <jrusgrove at comcast.net>
To: <600mrg at w7ekb.com>
Subject: Re: [600MRG] For discussion: Re: Top loading a vertical on
	LF/MF
Message-ID: <006801ceebcf$fa9528c0$6401a8c0 at JAYDELL>
Content-Type: text/plain; format=flowed; charset="Windows-1252";
	reply-type=original

Neil

http://www.strobbe.eu/on7yd/136ant/

Scroll about 1/8 of the way down the page. Equations and graphs for tophat slope 
/ length vs. Rr 
improvement. For 137 kHz but also applies to 500 kHz.

The whole piece is a good read if interested in short verticals.

Jay W1VD  WD2XNS  WE2XGR/2  WG2XRS/2

----- Original Message ----- 
From: "Neil Klagge" <w0yse.7 at gmail.com>
To: <600mrg at w7ekb.com>
Sent: Wednesday, November 27, 2013 6:18 PM
Subject: [600MRG] For discussion: Re: Top loading a vertical on LF/MF

To the 600m gang:
The reason for initiating this discussion is that, for me and perhaps
others, it is not feasible or possible to add top loading wires to a 630m
vertical without sloping the load wires downward a considerable amount.

I know that when an antenna is ?folded back on itself? there is
cancellation of some of the radiation from the antenna. This is certainly
the case for top loading wires that reach toward the ground down to less
than half of the height of the vertical section.

The question I find myself asking is this: ?Is what I will gain in ERP
worth the effort it takes to add sloping top wires because of the
cancellation that will occur.? I wonder if 1 or 2 dB gain is worth it at
the receiving end.

I would be interested in feedback from those who have any experience with
both situations: Namely, top loaded verticals and ?topless? verticals  ;-)

73, Neil Klagge, WG2XSV, W0YSE

-- 
*"I use the original form of social networking, Amateur Radio." *
              *(my ham radio site is at 'w0yse.webs.com
<http://w0yse.webs.com/>' )*
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------------------------------

Message: 3
Date: Wed, 27 Nov 2013 19:02:32 -0600
From: "Pat Hamel" <pehamel at cableone.net>
To: "'Neil Klagge'" <w0yse.7 at gmail.com>,	<600mrg at w7ekb.com>
Subject: Re: [600MRG] For discussion: Re: Top loading a vertical on
	LF/MF
Message-ID: <E01DB79813A84C62BA14C8770EDE0FD1 at MrSamPC>
Content-Type: text/plain;	charset="us-ascii"

For antenna planning, please look at:
http://www.500kc.com/downloads/Martin-Carter%20(RCA)%20LF%20Antennas.pdf
for information that might help.
Actually before spending money, you might look at all the "technical
downloads" in the downloads tab of www.500kc.com
The umbrella antenna (sloping top loading) has a lower effective height
because of the cancellation idea. The wire around the outside supposedly
helps efficiency a lot.
The only way I could get full top loading was to go with the inverted - L
idea with eleven 120 foot wires on copper pipe spreaders. 
When we dropped to 475KC, I added a (40 microhenry max) roller coil at the
bottom.
Happy Thanksgiving
Pat /6

-----Original Message-----
From: 600MRG [mailto:600mrg-bounces at w7ekb.com] On Behalf Of Neil Klagge
Sent: Wednesday, November 27, 2013 5:18 PM
To: 600mrg at w7ekb.com
Subject: [600MRG] For discussion: Re: Top loading a vertical on LF/MF

 To the 600m gang:
The reason for initiating this discussion is that, for me and perhaps
others, it is not feasible or possible to add top loading wires to a 630m
vertical without sloping the load wires downward a considerable amount.

I know that when an antenna is "folded back on itself" there is
cancellation of some of the radiation from the antenna. This is certainly
the case for top loading wires that reach toward the ground down to less
than half of the height of the vertical section.

The question I find myself asking is this: "Is what I will gain in ERP
worth the effort it takes to add sloping top wires because of the
cancellation that will occur." I wonder if 1 or 2 dB gain is worth it at
the receiving end.

I would be interested in feedback from those who have any experience with
both situations: Namely, top loaded verticals and "topless" verticals  ;-)

73, Neil Klagge, WG2XSV, W0YSE

-- 
*"I use the original form of social networking, Amateur Radio." *
              *(my ham radio site is at 'w0yse.webs.com
<http://w0yse.webs.com/>' )*
_______________________________________________
600MRG mailing list
600MRG at w7ekb.com
http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com

------------------------------

Message: 4
Date: Wed, 27 Nov 2013 19:17:35 -0800 (PST)
From: Ken Roberson <kwroberson at yahoo.com>
To: "600MRG at w7ekb.com" <600MRG at w7ekb.com>
Subject: [600MRG] Neil -  Vertical top loading
Message-ID:
	<1385608655.86704.YahooMailNeo at web142701.mail.bf1.yahoo.com>
Content-Type: text/plain; charset=us-ascii

Neil,

I installed 3 sloping wires on my 60 ft vertical, Each wire is
45 ft . The ends are 35 ft above the ground, It seems to me
That indeed it helped and I was able to remove 20 turns
from my base loading coil, That had to help.
Photo on QRZ.
73 Ken K5DNL

------------------------------

Message: 5
Date: Wed, 27 Nov 2013 19:58:50 -0800
From: "Rudy Severns" <n6lf at arrl.net>
To: "600MRG" <600mrg at w7ekb.com>
Subject: [600MRG] /20
Message-ID: <5E00FE77B51946F7A8A6035D29B65BBD at Rudy>
Content-Type: text/plain; format=flowed; charset="Windows-1252";
	reply-type=original

Another strange evening!  I can see and hear XJM's WSPR signal.  He's 
decoding at -6 dB which is very strong.  This is the first time I've seen an 
actual trace for a WSPR signal.  However, all the other signals are very 
light.  I can see a trace for /12 but not hear him.  No sign of Ralph, /7, 
yet.  Why is XJM exceptional and everyone else is weak???

Will continue to monitor.

73, Rudy 

------------------------------

Message: 6
Date: Wed, 27 Nov 2013 22:12:10 -0600
From: "Ralph Hartwell" <w5jgv at w5jgv.com>
To: "'600MRG'" <600mrg at w7ekb.com>
Subject: Re: [600MRG] /20
Message-ID: <00f301ceebf0$0b46c9b0$21d45d10$@w5jgv.com>
Content-Type: text/plain;	charset="us-ascii"

>No sign of Ralph, /7, yet.  Why is
> XJM exceptional and everyone else is weak???

Dunno', but I'm doing my part to fill the power company's coffers what with
the 4-400A amplifier throwing amps at the antenna. But I need the heat in
the shack tonight - it's getting close to 20 degrees here overnight, which
is downright cold for us.

Best DX & 73,

Ralph  W5JGV - WD2XSH/7

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Message: 7
Date: Wed, 27 Nov 2013 22:16:05 -0600
From: Mike-WE0H <we0h at yahoo.com>
To: 600mrg at w7ekb.com
Subject: Re: [600MRG] /20
Message-ID: <5296C385.6040904 at yahoo.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

20F ??? It's warmer up here :-) 25F and clear skies. No snow :-)

Mike
WE0H
/16

Ralph  wrote:

...- it's getting close to 20 degrees here overnight, which
is downright cold for us.

Best DX & 73,

Ralph  W5JGV - WD2XSH/7

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