Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/10/2022 1:13 PM, Jim Brown wrote:
As usual, I agree with Rick.  But I'd like to observe that an extensive 
study of loaded mobile whips published in two parts in QEX about ten 
years ago showed that inductive loading, especially at the base, was a 



73, Jim K9YC



I wasn't clear.  I assumed that the vertical has top loading wires, and
the base loading inductor is added to get resonance.  According to W8JI,
once you have enough top loading to get uniform current in the vertical, 
then it is OK to have a base mounted tuning inductor.  For short 
verticals, making the top wires extremely long to achieve resonance 
without a loading coil is sub optimal because it reduces the radiation 
resistance too much.  I once resonated a 60 foot vertical on 160 meters 
using two 100 foot top umbrella wires, because it was a temporary 
antenna and I didn't want to fool with a loading coil.  The drive 
impedance was very low.


73
Rick N6RK
_
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Re: Topband: Radials on ground v FCP

[Lee STRAHAN]

According to Roy Lewallens Eznec site there are no more expensive versions of 
his Eznec software. He is retiring and is leaving a last version for free 
download.
Take a look at Eznec.com for details.
Lee  K7TJR  OR

-Original Message-
From: Topband  On Behalf Of Jim 
Brown
Sent: Monday, January 10, 2022 1:13 PM
To: topband@contesting.com
Subject: Re: Topband: Radials on ground v FCP

As usual, I agree with Rick.  But I'd like to observe that an extensive study 
of loaded mobile whips published in two parts in QEX about ten years ago showed 
that inductive loading, especially at the base, was a bad idea, and that the 
closer loading moved to the top, the more efficient was the radiated field. The 
published work included extensive measurements of various positions of the 
loading, with top loading being the best. Which is what we're doing with both 
the L and the T.

One fly in the ointment in our understanding is that most modeling software, 
especially if it models inductive loading as a lumped element, fails to 
correctly model the phase of current through the inductor. Some years ago, W7EL 
added a method of modeling inductors using his EZNEC interface as a large 
number of small inductors in a spiral geometry, in an attempt to correct for 
this. Thus a practical inductor could include hundreds of (or even a thousand) 
elements, so it requires one of the more expensive versions of his software, 
and takes a while to crank.

73, Jim K9YC

On 1/10/2022 11:24 AM, Richard (Rick) Karlquist wrote:
> Actually, you are kidding yourself making the inverted L long enough 
> to be resonant.  That has the effect of moving more current into the 
> horizontal part of the inverted L, which is also not desirable.  The 
> solution to this dilemma is to use a top loaded (T type) vertical, and 
> a loading coil if necessary.  The resonant inverted L is "elegant" but 
> not optimal.

_
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Re: Topband: Radials on ground v FCP

[Jim Brown]

As usual, I agree with Rick.  But I'd like to observe that an extensive 
study of loaded mobile whips published in two parts in QEX about ten 
years ago showed that inductive loading, especially at the base, was a 
bad idea, and that the closer loading moved to the top, the more 
efficient was the radiated field. The published work included extensive 
measurements of various positions of the loading, with top loading being 
the best. Which is what we're doing with both the L and the T.


One fly in the ointment in our understanding is that most modeling 
software, especially if it models inductive loading as a lumped element, 
fails to correctly model the phase of current through the inductor. Some 
years ago, W7EL added a method of modeling inductors using his EZNEC 
interface as a large number of small inductors in a spiral geometry, in 
an attempt to correct for this. Thus a practical inductor could include 
hundreds of (or even a thousand) elements, so it requires one of the 
more expensive versions of his software, and takes a while to crank.


73, Jim K9YC

On 1/10/2022 11:24 AM, Richard (Rick) Karlquist wrote:
Actually, you are kidding yourself making the inverted L long enough to 
be resonant.  That has the effect of moving more current into the 
horizontal part of the inverted L, which is also not desirable.  The 
solution to this dilemma is to use a top loaded (T type) vertical, and a 
loading coil if necessary.  The resonant inverted L is "elegant" but not 
optimal.


_
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Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/10/2022 10:42 AM, Kenny Silverman wrote:

N6BT’s ring is pretty flexible in its dimensions. It can be 3 or 4 sides (or 
anywhere in between) and can handle some variation in symmetry.

I’ve been having issues finding a solution to the high tree attenuation on my 
property and I had an inverted L with the ring and another inverted L 340’ away 
with 60 x 100’ radials.  The model showed there was some interaction between 
the 2 antennas so exact difference was not known. But basically the ring was 
very close to the 60 radial version.

One of the key issues is making sure the inverted L section is close to 
resonance. If it’s short, more current is moved into the ring which is not 
desirable.

Regards , Kenny K2KW
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Actually, you are kidding yourself making the inverted L long enough to 
be resonant.  That has the effect of moving more current into the 
horizontal part of the inverted L, which is also not desirable.  The 
solution to this dilemma is to use a top loaded (T type) vertical, and a 
loading coil if necessary.  The resonant inverted L is "elegant" but not 
optimal.


Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[Kenny Silverman]

N6BT’s ring is pretty flexible in its dimensions. It can be 3 or 4 sides (or 
anywhere in between) and can handle some variation in symmetry. 

I’ve been having issues finding a solution to the high tree attenuation on my 
property and I had an inverted L with the ring and another inverted L 340’ away 
with 60 x 100’ radials.  The model showed there was some interaction between 
the 2 antennas so exact difference was not known. But basically the ring was 
very close to the 60 radial version.   

One of the key issues is making sure the inverted L section is close to 
resonance. If it’s short, more current is moved into the ring which is not 
desirable. 

Regards , Kenny K2KW 
_
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Re: Topband: Radials on ground v FCP

[CUTTER DAVID via Topband]

I took my inspiration for the one turn counterpoise idea from HF Antenna For 
All Locations page 155, Fig 11.9(m). 

David G3UNA


> On 09 January 2022 at 17:09 CUTTER DAVID via Topband  
> wrote:
> 
> 
> Thanks, Rick.  
> 
> My particular circumstances limit me to a small triangle of ground in the 
> corner of a field and the FCP suits that very well.  It would be interesting 
> to know how the FCP compares to something well known, like a broadcast 
> station ground.  
> 
> I like the idea of the spiral counterpoise:  I experimented with a one turn 
> counterpoise in EZNEC
> at 3 m above ground level.  It looked workable but too big for my space, so, 
> I could make that into a spiral and perhaps not be too concerned about 
> symmetry.  However, looking to Guy's idea of stacking the wires vertically so 
> they  shade the ground underneath might be worth a try. Compressing things 
> always seems to limit bandwidth, so, that's something to be wary of.  
> 
> David G3UNA  
> 
>  
> > On 09 January 2022 at 16:22 "Richard (Rick) Karlquist" 
> >  wrote:
> > 
> > 
> > 
> > On 1/9/2022 4:51 AM, CUTTER DAVID via Topband wrote:
> > > Hi Rob
> > > 
> > > I see copper prices have doubled in the last year.
> > > 
> > > My intention is to compare and contrast the cost and performance of short 
> > > verticals over a large field of ground radials v the very modest amount 
> > > of wire required for the FCP.  In Guy's article
> > > 
> > 
> > This is a false dichotomy between FCP and a broadcast station ground 
> > screen.  The best use of wire is to have a small number of elevated 
> > tuned radials with proper RF choking.  As shown by N6LF, you can do well 
> > with just 8 radials, about 100 feet long each.  On 160 meters, they 
> > should be 20 feet high for optimum performance.  BTW, cheap aluminum 
> > electric fence wire works perfectly for elevated radials  Also consider 
> > N6BT's single spiral radial configuration as an alternative to FCP.
> > 
> > Rick N6RK
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/9/2022 8:22 AM, Richard (Rick) Karlquist wrote:



electric fence wire works perfectly for elevated radials  Also consider 
N6BT's single spiral radial configuration as an alternative to FCP.


Rick N6RK
_


See:

https://nextgenerationantennas.com/presentations-1

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[CUTTER DAVID via Topband]

Thanks, Rick.  

My particular circumstances limit me to a small triangle of ground in the 
corner of a field and the FCP suits that very well.  It would be interesting to 
know how the FCP compares to something well known, like a broadcast station 
ground.  

I like the idea of the spiral counterpoise:  I experimented with a one turn 
counterpoise in EZNEC
at 3 m above ground level.  It looked workable but too big for my space, so, I 
could make that into a spiral and perhaps not be too concerned about symmetry.  
However, looking to Guy's idea of stacking the wires vertically so they  shade 
the ground underneath might be worth a try. Compressing things always seems to 
limit bandwidth, so, that's something to be wary of.  

David G3UNA  

 
> On 09 January 2022 at 16:22 "Richard (Rick) Karlquist" 
>  wrote:
> 
> 
> 
> On 1/9/2022 4:51 AM, CUTTER DAVID via Topband wrote:
> > Hi Rob
> > 
> > I see copper prices have doubled in the last year.
> > 
> > My intention is to compare and contrast the cost and performance of short 
> > verticals over a large field of ground radials v the very modest amount of 
> > wire required for the FCP.  In Guy's article
> > 
> 
> This is a false dichotomy between FCP and a broadcast station ground 
> screen.  The best use of wire is to have a small number of elevated 
> tuned radials with proper RF choking.  As shown by N6LF, you can do well 
> with just 8 radials, about 100 feet long each.  On 160 meters, they 
> should be 20 feet high for optimum performance.  BTW, cheap aluminum 
> electric fence wire works perfectly for elevated radials  Also consider 
> N6BT's single spiral radial configuration as an alternative to FCP.
> 
> Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/9/2022 4:51 AM, CUTTER DAVID via Topband wrote:

Hi Rob

I see copper prices have doubled in the last year.

My intention is to compare and contrast the cost and performance of short 
verticals over a large field of ground radials v the very modest amount of wire 
required for the FCP.  In Guy's article



This is a false dichotomy between FCP and a broadcast station ground 
screen.  The best use of wire is to have a small number of elevated 
tuned radials with proper RF choking.  As shown by N6LF, you can do well 
with just 8 radials, about 100 feet long each.  On 160 meters, they 
should be 20 feet high for optimum performance.  BTW, cheap aluminum 
electric fence wire works perfectly for elevated radials  Also consider 
N6BT's single spiral radial configuration as an alternative to FCP.


Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[CUTTER DAVID via Topband]

Hi Rob

I see copper prices have doubled in the last year.

My intention is to compare and contrast the cost and performance of short 
verticals over a large field of ground radials v the very modest amount of wire 
required for the FCP.  In Guy's article 

https://k2av.com/Olinger_NCJ_article_on_FCP.pdf

he says "The reason for the FCP is twofold: minimal space and a low-loss 
alternative to radials."  I would add that it is also lower cost, to your 
point.  

I interpret his analysis as saying that the layout of the FCP minimises its own 
ground loss so well that only the radiator's ground loss is left to compare to 
the "gold standard" of 120 ground radials.

I hope someone will jump in and correct me if I've misinterpreted that.  If 
not, would it be correct to say that the FCP method of loss reduction differs 
only by 1.7 dB (from Guy's article) compared to the "gold standard" of 120 
ground radials?  

I don't have that Griffith book, so, would you summarise the difference between 
120 ground radials and the fewer radials proposed when using <1/4 w vertical?  
I'd like to get a feel for how it compares to the FCP method. 

73 David G3UNA
 

> On 08 January 2022 at 18:14 Rob Atkinson  wrote:
> 
> 
> I can't comment on the folded counterpoise because I am not familiar
> with it.  The "broadcast model" which I take to mean 120 radials is
> used because in the case of a 90 degree tower on medium wave, the
> earth current intensity is far enough from the feed point to
> necessitate a higher number of radials so that as they diverge, they
> are not so far apart from each other that the earth losses are
> unacceptable.  Few hams have 1/4 w. towers for 160 m., and instead
> employ shorter vertical radiators such as inverted Ls* and Ts, (1/8 w.
> for example) so the ground current intensity is high much closer to
> the feedpoint.  This means that fewer radials can be used because they
> are shorter and at their ends, are still an acceptable separation from
> each other.  Of course, ground conductivity plays a part also.  This
> is good news for hams who want to save money on expensive wire.  All
> of this is detailed in the Griffith book I referenced previously.
> 
> 73
> Rob
> K5UJ
> 
> *Unlike the T, the horizontal portion of the inverted L radiates.
> W1BB recommended extending radials that run along underneath it if
> possible, and I think that was good advice.
> 
> On Sat, Jan 8, 2022 at 9:27 AM CUTTER DAVID  wrote:
> >
> > Rob
> >
> > I recall a discussion on here some years ago which proposed that, whilst 
> > being an amazing antenna for top band, if you could achieve it, the 
> > broadcast model was not necessarily the best use of resources for amateur 
> > purposes, on the basis that broadcasters are mainly interested in ground 
> > wave to cover a defined relatively short range service area, whereas 
> > amateurs a more interested in dx.
> >
> > I don't recall how that discussion ended, but for purposes of saving wire, 
> > at least, the K2AV folded counterpoise (FCP) must be about as good as 
> > anyone could attain.  How it performs against that broadcast model would be 
> > of interest.
> >
> > David G3UNA
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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Re: Topband: Radials on ground

[on7eh]

Dear all,

Anyone in Europe willing to sell its used 2nd ed. Griffith book?
Please send me a private mail.

Thanks,
Seasons greetings,

Michel, ON7EH


-Original Message- 
From: Rob Atkinson 
Sent: Saturday, January 8, 2022 3:02 PM 
To: topband@contesting.com 
Subject: Re: Topband: Radials on ground 


For medium wave, every ham who transmits with a base excited vertical
radiator should get a copy of _Radio-Electronic Transmission
Fundamentals_ by B. Whitfield Griffith, Jr.  2nd ed., Noble Pub. Co.,
Atlanta Ga., c2000, ISBN 1884932134.  638 p.  Griffith is a retired
principal engineer with Continental.  This classic college broadcast
engineer textbook explains many fundamentals involving medium wave
transmission in an easy to understand way.  Getting the most out of
your valuable copper wire is more important now than ever because
copper has risen to insanely high prices.

The book is probably out of print but might be available used from ABE
Books https://www.abebooks.com/

73
Rob
K5UJ
_
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_
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Re: Topband: Radials on ground v FCP

[Jim Brown]

Hi Frank,

It was definitely Cleveland. Got my abbreviations wrong after 60 years. :)

Thanks, Jim

On 1/8/2022 12:10 PM, Frank W3LPL wrote:

Hi Jim,

Didn't Carl Smith run CIE (Cleveland Institute of Electronics)
and not CREI (Capitol Radio Engineering Institute)?

73
Frank
W3LPL

- Original Message -
From: "K9YC" 
To: "topband" 
Sent: Saturday, January 8, 2022 5:36:03 PM
Subject: Re: Topband: Radials on ground v FCP

On 1/8/2022 7:27 AM, CUTTER DAVID via Topband wrote:

I recall a discussion on here some years ago which proposed that, whilst being 
an amazing antenna for top band, if you could achieve it, the broadcast model 
was not necessarily the best use of resources for amateur purposes, on the 
basis that broadcasters are mainly interested in ground wave to cover a defined 
relatively short range service area, whereas amateurs a more interested in dx.


The function of radial systems under a vertical radiator is solely to
minimize loss in the very near field. That has nothing to do with the
means of propagation -- i.e., ground wave vs skywave. With directional
arrays of verticals, widely used it broadcasting as well as ham radio,
they have a second function, directly related to the first, of
controlling the nulls in the pattern by minimizing differences the
contribution of each element by making those losses as small as possible.

Radial systems in broadcasting are (or at least were) controlled because
licenses were granted on the basis of carefully controlled coverage
areas, and for protection of other stations on the same or adjacent
channels. I learned about this as an EE student, working in the
consulting office of Pete Johnson, whose practice was designing these
arrays to fit new stations into the AM band that had been full for 20
years. Pete and Carl Smith (who ran CREI) wrote FCC AM technical Rules
after WWII.

73, Jim K9YC


_
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Re: Topband: Radials on ground v FCP

[Wes]

On 1/8/2022 8:27 AM, CUTTER DAVID via Topband wrote:

Rob

I recall a discussion on here some years ago which proposed that, whilst being 
an amazing antenna for top band, if you could achieve it, the broadcast model 
was not necessarily the best use of resources for amateur purposes, on the 
basis that broadcasters are mainly interested in ground wave to cover a defined 
relatively short range service area, whereas amateurs a more interested in dx.
Without arguing the "best use of resources" issue, work on the ground screen 
that improves ground wave will also improve sky wave (DX)

I don't recall how that discussion ended, but for purposes of saving wire, at 
least, the K2AV folded counterpoise (FCP) must be about as good as anyone could 
attain.  How it performs against that broadcast model would be of interest.

David G3UNA
Maybe it saves wire, but IMHO, it's a terrible ground screen.  To see what I 
mean by "ground screen" I quote a post to this reflector by my friend Eric, 
N7CL, from a long time ago.


Wes  N7WS

Quote:
To:     
Subject:     TopBand: Elevated GP vs. Vertical Antennas
From:     n...@mmsi.com (Eric Gustafson Courtesy Account)
Date:     Fri, 13 Mar 1998 17:14:28 -0700

I apologize for this but I'm not directly responding to the post
of yours referred to in the header of this message.  I Just
grabbed it to respond to because it was a convenient way to get
the subject references correct.  I don't believe that the quoted
insert from Tom is taken from that message.

>In a message dated 98-03-08 19:05:39 EST, W8JI writes:
>
>> The 160 meter skin depth (distance where current drops to 37%
>> of the value traveling in the conductor) is about 30 meters in
>> poor soil, ten meters in good soil, and about a foot in salt
>> water. Current effectively goes to zero at about 10 skin
>> depths.
>
>

The above is a very interesting statement.  Let me see if I can
make use of it to illuminate _why_ the full ground screen (either
on or in the ground surface) provides a system with less loss
than a system of six or fewer elevated radials.

First, I'd like to separate the discussion to a strict comparison
of one ground system versus the other when used to provide the
ground system for (nearly at least) identical vertical
radiators.  Please note that I'm NOT saying that elevated radials
don't work, or that they don't work well enough to make a useful
antenna.  Only that when used near the earth's surface, they
cannot provide the same high level of efficiency as the canonical
full size sufficiently dense ground screen under the same
radiator.  We are talking about ground mounted (less than 1/8
wave above grade) vertical radiators which are less than or equal
to 1/4 wave long.

The quantity of DX that can be worked with tuned rain gutters is
irrelevant to this discussion.  The only thing we are talking
about is how many dB stronger (or weaker) is the same radiator
with ground system (A) versus the same antenna with ground system
(B).

Frequently it is possible to work DX effectively even on topband
with an antenna that is 25 dB weaker than a full size, full
effeciency vertical.  This is because the fade margin for the big
antenna is 50 or 60 dB and -25 dB doesn't take the link SNR below
zero.  Here we are talking about two systems which are within 4
to 6 dB of each other.


OK Now, from Tom's statement above it is pretty clear that unless
some means is taken to prevent the antenna's near field zone from
"seeing" the earth under the antenna, a large volume of earth
will be involved in the near field interaction.  The poorer the
earth conductivity is, the larger the volume will be that is
involved.  As the apparent surface conductivity of the earth's
surface increases (or is artificially increased with radials),
the volume of lossy earth exposed to the near fields decreases.
Eventually a point is reached where further surface conductivity
increases do not produce lower losses because the dominant loss
mechanism for the antenna system is no longer the near field
interaction loss with the earth material.

The effect of increasing the surface conductivity has been to
prevent the fields from penetrating into the earth material under
the antenna.  Hence the name "ground screen".  The ground system
when sufficiently dense has "screened" or shielded the earth
material from the antenna's near fields.

Sufficiently dense means that the greatest distance between
conductors in the screen is 0.015 wavelengths or less.  For 1/4
wavelength radials, this requirement is met with 104 radials.
Now, as a practical matter, relaxing the criteria to 0.03
wavelengths for a radial system results in only about a 0.5 dB
reduction in measured field strength.  So 60 radials this long
would produce a system which is very nearly as good as one
meeting the full density criteria.

For radials only 1/8 wavelength long, the requirement is met with
only 52 radials (26 if you are willing to give up 0.5 dB).  Note
that these numbers are very con

Re: Topband: Radials on ground v FCP

[Rob Atkinson]

I can't comment on the folded counterpoise because I am not familiar
with it.  The "broadcast model" which I take to mean 120 radials is
used because in the case of a 90 degree tower on medium wave, the
earth current intensity is far enough from the feed point to
necessitate a higher number of radials so that as they diverge, they
are not so far apart from each other that the earth losses are
unacceptable.  Few hams have 1/4 w. towers for 160 m., and instead
employ shorter vertical radiators such as inverted Ls* and Ts, (1/8 w.
for example) so the ground current intensity is high much closer to
the feedpoint.  This means that fewer radials can be used because they
are shorter and at their ends, are still an acceptable separation from
each other.  Of course, ground conductivity plays a part also.  This
is good news for hams who want to save money on expensive wire.  All
of this is detailed in the Griffith book I referenced previously.

73
Rob
K5UJ

*Unlike the T, the horizontal portion of the inverted L radiates.
W1BB recommended extending radials that run along underneath it if
possible, and I think that was good advice.

On Sat, Jan 8, 2022 at 9:27 AM CUTTER DAVID  wrote:
>
> Rob
>
> I recall a discussion on here some years ago which proposed that, whilst 
> being an amazing antenna for top band, if you could achieve it, the broadcast 
> model was not necessarily the best use of resources for amateur purposes, on 
> the basis that broadcasters are mainly interested in ground wave to cover a 
> defined relatively short range service area, whereas amateurs a more 
> interested in dx.
>
> I don't recall how that discussion ended, but for purposes of saving wire, at 
> least, the K2AV folded counterpoise (FCP) must be about as good as anyone 
> could attain.  How it performs against that broadcast model would be of 
> interest.
>
> David G3UNA
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[Jim Brown]

On 1/8/2022 7:27 AM, CUTTER DAVID via Topband wrote:

I recall a discussion on here some years ago which proposed that, whilst being 
an amazing antenna for top band, if you could achieve it, the broadcast model 
was not necessarily the best use of resources for amateur purposes, on the 
basis that broadcasters are mainly interested in ground wave to cover a defined 
relatively short range service area, whereas amateurs a more interested in dx.


The function of radial systems under a vertical radiator is solely to 
minimize loss in the very near field. That has nothing to do with the 
means of propagation -- i.e., ground wave vs skywave. With directional 
arrays of verticals, widely used it broadcasting as well as ham radio, 
they have a second function, directly related to the first, of 
controlling the nulls in the pattern by minimizing differences the 
contribution of each element by making those losses as small as possible.


Radial systems in broadcasting are (or at least were) controlled because 
licenses were granted on the basis of carefully controlled coverage 
areas, and for protection of other stations on the same or adjacent 
channels. I learned about this as an EE student, working in the 
consulting office of Pete Johnson, whose practice was designing these 
arrays to fit new stations into the AM band that had been full for 20 
years. Pete and Carl Smith (who ran CREI) wrote FCC AM technical Rules 
after WWII.


73, Jim K9YC


_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[CUTTER DAVID via Topband]

Rob

I recall a discussion on here some years ago which proposed that, whilst being 
an amazing antenna for top band, if you could achieve it, the broadcast model 
was not necessarily the best use of resources for amateur purposes, on the 
basis that broadcasters are mainly interested in ground wave to cover a defined 
relatively short range service area, whereas amateurs a more interested in dx.  

I don't recall how that discussion ended, but for purposes of saving wire, at 
least, the K2AV folded counterpoise (FCP) must be about as good as anyone could 
attain.  How it performs against that broadcast model would be of interest.

David G3UNA


 
> On 08 January 2022 at 14:02 Rob Atkinson  wrote:
> 
> 
> For medium wave, every ham who transmits with a base excited vertical
> radiator should get a copy of _Radio-Electronic Transmission
> Fundamentals_ by B. Whitfield Griffith, Jr.  2nd ed., Noble Pub. Co.,
> Atlanta Ga., c2000, ISBN 1884932134.  638 p.  Griffith is a retired
> principal engineer with Continental.  This classic college broadcast
> engineer textbook explains many fundamentals involving medium wave
> transmission in an easy to understand way.  Getting the most out of
> your valuable copper wire is more important now than ever because
> copper has risen to insanely high prices.
> 
> The book is probably out of print but might be available used from ABE
> Books https://www.abebooks.com/
> 
> 73
> Rob
> K5UJ
> _
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Re: Topband: Radials on ground

[Rob Atkinson]

For medium wave, every ham who transmits with a base excited vertical
radiator should get a copy of _Radio-Electronic Transmission
Fundamentals_ by B. Whitfield Griffith, Jr.  2nd ed., Noble Pub. Co.,
Atlanta Ga., c2000, ISBN 1884932134.  638 p.  Griffith is a retired
principal engineer with Continental.  This classic college broadcast
engineer textbook explains many fundamentals involving medium wave
transmission in an easy to understand way.  Getting the most out of
your valuable copper wire is more important now than ever because
copper has risen to insanely high prices.

The book is probably out of print but might be available used from ABE
Books https://www.abebooks.com/

73
Rob
K5UJ
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Re: Topband: Radials on ground

[Carl Braun]

Topbanders

Here is my favorite article on ground radials by Al Christman K3LC.  
https://ncjweb.com/bonus-content/k3lcmaxgainradials.pdf

Great reading but I continue to add more radials thus exceeding Al's suggested 
number.  I also use Eight 3" aluminum irrigation pipes under each vertical that 
are 30' long in conjunction with 50 100' long wire radials.  I use the 
irrigation pipe as radials rather than stack them behind the garage waiting for 
the price of aluminum to peak.

73, Carl W9LF


-Original Message-
From: Topband  On Behalf 
Of Jim Brown
Sent: Friday, January 7, 2022 12:36 PM
To: topband@contesting.com
Subject: Re: Topband: Radials on ground

CAUTION: This email originated outside of the organization. This message might 
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On 1/7/2022 6:14 AM, Pete Smith N4ZR wrote:
> is the size of wire used for on-the-ground radials - or elevated 
> radials for that matter - significant?

The only significance is their mechanical characteristics to withstand physical 
conditions.

 > at least as compared to feeding the antenna against a single ground  > rod.

The earth is a big resistor. We do NOT want a connection to it, except for 
lightning protection. Indeed, radials have two functions -- to provide a low 
resistance path for the antenna's return current, and to SHIELD the antenna's 
field from the lossy earth.

The only antennas whose performance benefit from an earth connection are 
receiving antennas.

Conversations here can point us to consider other options, but are not a 
substitute for serious study of fundamentals. Real understanding of how stuff 
works is better obtained by study of the Handbook, the Antenna Book, and the 
ON4UN book.

Rudy Severns, N6LF, has done a LOT of excellent work, in the form of 
interactive modeling concepts, building and measuring radial systems, modeling 
some more, and building measuring some more, then publishing what he's done and 
what he's learned. It's also well worth studying.
https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.antennasbyn6lf.com%2F&data=04%7C01%7CCarl.Braun%40cattron.com%7Cd80402cf63804d67fdd808d9d20c996c%7Ce3db7da86f894250a548d36f358a7d2a%7C0%7C0%7C637771774496971841%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=626vCzmEvqb1EpFh3eoEfr75LZDkDdenVM5y5VqU8IE%3D&reserved=0
  Going to his site to find this link, I see that since my last visit, he's 
published some work on loop and loop on ground RX antennas.

Almost ten years ago, I summarized what I'd learned from others on the topic of 
160M antenna systems for limited space in a talk I've done at Visalia, 
Pacificon, and for several clubs including NCCC. Most of it is about radial and 
counterpoise systems. None of it is original work on my part. The slides are 
here. 
https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.antennasbyn6lf.com%2F&data=04%7C01%7CCarl.Braun%40cattron.com%7Cd80402cf63804d67fdd808d9d20c996c%7Ce3db7da86f894250a548d36f358a7d2a%7C0%7C0%7C637771774496971841%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=626vCzmEvqb1EpFh3eoEfr75LZDkDdenVM5y5VqU8IE%3D&reserved=0

73, Jim K9YC
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Re: Topband: Radials on ground

[Jim Brown]

On 1/7/2022 6:14 AM, Pete Smith N4ZR wrote:
is the size of wire used for on-the-ground radials - or elevated radials 
for that matter - significant?


The only significance is their mechanical characteristics to withstand 
physical conditions.


> at least as compared to feeding the antenna against a single ground
> rod.

The earth is a big resistor. We do NOT want a connection to it, except 
for lightning protection. Indeed, radials have two functions -- to 
provide a low resistance path for the antenna's return current, and to 
SHIELD the antenna's field from the lossy earth.


The only antennas whose performance benefit from an earth connection are 
receiving antennas.


Conversations here can point us to consider other options, but are not a 
substitute for serious study of fundamentals. Real understanding of how 
stuff works is better obtained by study of the Handbook, the Antenna 
Book, and the ON4UN book.


Rudy Severns, N6LF, has done a LOT of excellent work, in the form of 
interactive modeling concepts, building and measuring radial systems, 
modeling some more, and building measuring some more, then publishing 
what he's done and what he's learned. It's also well worth studying. 
https://www.antennasbyn6lf.com/  Going to his site to find this link, I 
see that since my last visit, he's published some work on loop and loop 
on ground RX antennas.


Almost ten years ago, I summarized what I'd learned from others on the 
topic of 160M antenna systems for limited space in a talk I've done at 
Visalia, Pacificon, and for several clubs including NCCC. Most of it is 
about radial and counterpoise systems. None of it is original work on my 
part. The slides are here. https://www.antennasbyn6lf.com/


73, Jim K9YC
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Re: Topband: Radials on ground

[Artek Manuals]

Pete

I  was just  having this very discussion with some one else this week. 
We modeled a 100 ' tall T on 160 M with sixty-four 100' long radials 
using NEC-4. with that many radials there was essentially no discernible 
difference between #22 wire radials and #14 radials on average earth 
ground. If you want I'll run the analysis using NEC4 again against your 
smaller radial field later today. Give me the size of the vertical 
radiator(L, T or straight Vertical)


Dave

NR1DX

On 1/7/2022 9:14 AM, Pete Smith N4ZR wrote:
For the moment at least, I'm using on-the-ground radials for my 160M 
inverted L. Discussion on the reflector triggered a thought - is the 
size of wire used for on-the-ground radials - or elevated radials for 
that matter - significant?  I ask this because I have a huge spool of 
military-surplus, silver-plated (!) 18-gauge insulated copper wire.  
Currently using 16, +/- 1/8 wave on-the-ground radials made with the 
stuff.   Feedpoint resistance seems to be by the book, at least as 
compared to feeding the antenna against a single ground rod.



--
Dave manu...@artekmanuals.com www.ArtekManuals.com


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Re: Topband: Radials on ground

[Bob Garrett]

The size of the wire doesn’t matter one bit. Use what you have and enjoy. Just 
remember, the more radios the better and if you only have a choice of several 
long radios over multiple short ones go with the short ones

Sent from my iPhone 

> On Jan 7, 2022, at 9:14 AM, Pete Smith N4ZR  wrote:
> 
> For the moment at least, I'm using on-the-ground radials for my 160M 
> inverted L. Discussion on the reflector triggered a thought - is the size of 
> wire used for on-the-ground radials - or elevated radials for that matter - 
> significant?  I ask this because I have a huge spool of military-surplus, 
> silver-plated (!) 18-gauge insulated copper wire.  Currently using 16, +/- 
> 1/8 wave on-the-ground radials made with the stuff.   Feedpoint resistance 
> seems to be by the book, at least as compared to feeding the antenna against 
> a single ground rod.
> 
> -- 
> 73, Pete N4ZR
> Check out the new Reverse Beacon Network
> web server at.
> For spots, please use your favorite
> "retail" DX cluster.
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Topband: Radials on ground

[Pete Smith N4ZR]

For the moment at least, I'm using on-the-ground radials for my 160M 
inverted L. Discussion on the reflector triggered a thought - is the 
size of wire used for on-the-ground radials - or elevated radials for 
that matter - significant?  I ask this because I have a huge spool of 
military-surplus, silver-plated (!) 18-gauge insulated copper wire.  
Currently using 16, +/- 1/8 wave on-the-ground radials made with the 
stuff.   Feedpoint resistance seems to be by the book, at least as 
compared to feeding the antenna against a single ground rod.


--
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at.
For spots, please use your favorite
"retail" DX cluster.
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