[Lowfer] Overall Antenna Efficiency

Thu Oct 21 12:14:42 EDT 2010

I think you are correct in your observations Riese. The same theory
of " doubling " to obtain a 3dB gain applies to the ground radial
system, just the same as it does to a wire Top Hat. But again, the
biggest advantage of the radial system in a lowFER vertical is to
try to lower the resistance that the antenna see's from the earth 
beneath it.An antenna has to be doubled in size ( area covered ) 
to gain the supposed 3dB extra gain. So, it's I suppose all about 
" doubling " then. To get extra gain in whatever sense you are 
working on; you'll need to double what already exists. 
>From 4 to 8, from 8 to 16, from 16 to 32, and so on... this is where 
the law of diminishing returns starts to kick in. You will reach a 
point where it becomes too expensive, too large, or too whatever to
warrant the effort. 

73:


Andy - KU4XR - EM75xr - Friendsville, TN. USA
LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
Coordinates:  N:  35º 43' 54" - W:  84º 3' 16"

http://www.myspace.com/beaconxr

http://ku4xr.webs.com

http://lwca.org/community/YaBB.pl

*** The 5 most important words ever spoken ***

http://ku4xr.webs.com/5mostimportantwords.htm


--- On Thu, 10/21/10, riese-k3djc at juno.com <riese-k3djc at juno.com> wrote:

> From: riese-k3djc at juno.com <riese-k3djc at juno.com>
> Subject: Re: [Lowfer] Overall Antenna Efficiency
> To: lowfer at mailman.qth.net
> Date: Thursday, October 21, 2010, 11:39 AM
> Andy 
> 
> FYI 
> 
> I have 60 radials down for my 160 meter L
> If you relate antenna efficiency to band width
> I noticed in order to see a change I had to double the
> radial
> count,, going from 10 to 12 couldnt see much change had tp
> go to 20 to see a difference
> 
> This is just empirical observations, The wires are all
> short 40 +- feet
> and ran in only a 180 ^ direction but that was my feeling
> as I added them
> 
> Bob K3DJC 
> 
> 
> On Thu, 21 Oct 2010 08:23:19 -0700 (PDT) Andy - KU4XR
> <ku4xr at yahoo.com>
> writes:
> > Hi Lee, And lowFERs:
> > 
> > First the BIG DISCLAIMER: I am not an antenna engineer
> !!! I am an
> > experimenter... some like that, and some don't. I
> don't crunch the
> > numbers, BUT !!! those numbers are absolutley
> necessary, because 
> > it's
> > the antenna theory that the qualified engineers have
> used over the 
> > years to develop antenna systems with great
> efficiency. For my 
> > part;
> > this is a hobby, as it should be. I read a lot,
> understand some of 
> > it,
> > and some I don't. I'll leave the theory, and number
> crunching to 
> > the
> > guys who really understand it.
> > 
> > Now, my comment on the radials. I see the same thing
> that J.B. 
> > said,
> > signal radiation is not affected by my radial system
> as far as the
> > direction of strongest radiation. I only have radials
> laid out in a
> > 180 degree pattern, covering the NE, to SW directions,
> and that's
> > mainly because there's no need to run them underneath
> my mobile 
> > home.
> > The greatest benefit from the radial system is to
> lower the losses
> > from earth resistance as much as you can, because that
> is where the
> > biggest loss is at in a lowFER vertical antenna setup.
> Loops are of
> > course the exception, operating without the need for
> radials.
> > You will see a noticable directional enhancement
> effect with the 
> > radial system when the radials approach 1/4th
> wavelength at the 
> > operating frequency. It's very easy to see that we get
> no where
> > close to that length with our radials.
> > 
> > 73, and have a good day:
> > 
> > BTW; I noticed a very slight hint of my signal on
> Ralphs grabber
> > around  1:53 to 1:54 UTC which would be 8:53 am
> his local time.
> > That's still close enough to early morning that some
> skywave
> > could be present, but it is in there during daylight,
> even though
> > it's only a blip on the radar screen... Note #2; I
> have no radials
> > going in that direction either..
> > 
> > 
> > Andy - KU4XR - EM75xr - Friendsville, TN. USA
> > LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
> > Coordinates:  N:  35º 43' 54" - W: 
> 84º 3' 16"
> > 
> > http://www.myspace.com/beaconxr
> > 
> > http://ku4xr.webs.com
> > 
> > http://lwca.org/community/YaBB.pl
> > 
> > *** The 5 most important words ever spoken ***
> > 
> > http://ku4xr.webs.com/5mostimportantwords.htm
> > 
> > 
> > --- On Thu, 10/21/10, John Bruce McCreath <weazle at hurontel.on.ca>
> 
> > wrote:
> > 
> > > From: John Bruce McCreath <weazle at hurontel.on.ca>
> > > Subject: Re: [Lowfer] Overall Antenna Efficiency
> > > To: "Discussion of the Lowfer (US, European,
> & UK) and MedFer 
> > bands" <lowfer at mailman.qth.net>
> > > Date: Thursday, October 21, 2010, 9:18 AM
> > > Hello Lee, Lowfers,
> > > 
> > > My own findings with beacon EAR is that I've not
> noticed
> > > any favouritism in reception reports.  My
> > > antenna-radial
> > > system is basically a capital H laid on its side,
> with the
> > > two radials directly beneath the antenna. 
> The ends are
> > > in
> > > an NE-SW orientation, yet I've had good reports
> from
> > > stations broadside to it.  There you go for
> what it's
> > > worth.
> > > 
> > > 73, J.B., VE3EAR
> > > 
> > > LowFER Beacon "EAR"
> > > 188.830 kHz. QRSS30
> > > EN93dr
> > > 
> > > 
> > > 
> > > 
> > > 
> > >
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