## Re: [30MDG] 30/40 Meter Arrays, Status [1 Attachment]

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• Knowing that you are going with buried radials, I have a related question. It is difficult for me to determine, Dave, if the property is wide and deep enough
Message 1 of 7 , May 12 4:47 PM
Knowing that you are going with buried radials, I have a related question.

It is difficult for me to determine, Dave, if the property is wide and deep enough for a radial system of many (~32) quarter wave radials.  Is it?  If not, what radial strategy are you planning?

73,

Bill

• Hello Bill, I got lucky... The lot is long and narrow relative to itself, close to a 5:1 ratio... The lot is about 300 feet long, and about 60 feet wide, so
Message 2 of 7 , May 14 7:39 AM
Hello Bill,

I got lucky... The lot is long and narrow relative to itself, close to
a 5:1 ratio... The lot is about 300 feet long, and about 60 feet wide,
so I can just get radials in place for both a 30 meter four square, and
a 40 meter two element. Enclosed is a scaled map showing the antenna
locations on the lot, and the radials needed, to scale. I have also
added an image called "Array Context", showing the area for about 1/2
mile around my home. As you can see, I am on the edge of a huge open
area in the middle of a town... As I said, I got very lucky. My lot is
defined by the "A", from Google.

In the areas where the radials will be slightly short, (maybe 3 or 4
feet short), I am not going o worry about them... As far as I can tell
from about two weeks of heavy research, this will not make a major
difference. The return currents on the radials are highest close to the
antenna, and get lower as you go further out, so the effect of slightly
shortened radials "should" not be an issue.

It strikes me that a few shortened radials, while definitely making a
difference, will be so small a difference so as not to worry about. I
do worry about the pattern distortion though, but am not smart enough
with EZNEC yet to be able to model the arrays, and one takes what one
can get... In my case, I have been lucky so far...

I intend to lay out radials until I get only small changes in R for each
doubling of radials, as measured using an MFJ-259B... I will install
the antenna and follow these steps:

1. Take a R measurement.
3. Take another R measurement.
4. If difference between last to R measurements is something small,
then go to 6.
5. Goto 2
6. End

As you can tell I used to program, and I find that it helps to formalize
the steps being taken. In step 4, when I start approaching a less than
10% change, as I approach 36 Ohms, I will start thinking about stopping.
Once I get close to 36 Ohms... I'm done with radials...

If for some reason I get lazy, I will put a lot of shortened radials in,
as opposed to a few longer radials. Studies indicate that many shorter
radials are better than a few long ones. This is caused by the return
currents being highest near the base of the antenna, so more radials are
more effective than a few long ones. I will not get lazy though, I want
as perfect an array as possible for a ground mounted array, the thought
of elevating the array, and having 10 or so radials did cross my head,
but only for a moment...

I will be taking out my trusty RF Ammeter to look at each antenna after
the radials are in place... I want to insure the same power in each
antenna.

If you have any thoughts on this, good, or bad, please let me know
sooner than later... That goes for anyone looking at this... I would
layout.

I purchased two miles of wire for the radial field... :)

See:
and
http://www.antennasbyn6lf.com/files/antenna_ground_system_experiment_2.pdf

--
Thanks,
Dave
For Amateur Radio equipment reviews and setups see:
http://www.nk7z.net

On Sun, 2013-05-12 at 16:47 -0700, W. J. Karle wrote:
>
>
> Knowing that you are going with buried radials, I have a related
> question.
>
>
> It is difficult for me to determine, Dave, if the property is wide and
> deep enough for a radial system of many (~32) quarter wave radials.
> Is it? If not, what radial strategy are you planning?
>
>
> 73,
>
>
> Bill
>
>
>
>
>
>
>
>
Message 3 of 7 , May 16 5:34 PM
Dave:

The installation layout and your plan regarding when to stop laying radials both seem correct.

Someone mentioned concerns about BCI/TVI to nearby neighbours but I imagine that should be less of a problem than heretofore since not too many receivers are operating with  7 and 10MHz IFs  (or a harmonic thereof), although some do.

I have not run the curves but I wonder if neighbors' RF exposure will be below the published limits.

We all will be following your path to success.  Good luck.

73,

Bill

------------------------------------------------------------------------------------------------------
W. J. (Bill) Karle, VE4KZ
Amateur Radio Emergency Service -- Certified Emergency Coordinator

From: David Cole <dave@...>
To: 30MDG@yahoogroups.com
Sent: Tuesday, May 14, 2013 9:39:01 AM
Subject: Re: [30MDG] 30/40 Meter Arrays, Status [1 Attachment]

<*>[Attachment(s) from David Cole included below]

Hello Bill,

I got lucky...  The lot is long and narrow relative to itself, close to
a 5:1 ratio...  The lot is about 300 feet long, and about 60 feet wide,
so I can just get radials in place for both a 30 meter four square, and
a 40 meter two element.  Enclosed is a scaled map showing the antenna
locations on the lot, and the radials needed, to scale.  I have also
added an image called "Array Context", showing the area for about 1/2
mile around my home.  As you can see, I am on the edge of a huge open
area in the middle of a town...  As I said, I got very lucky.  My lot is
defined by the "A", from Google.

In the areas where the radials will be slightly short, (maybe 3 or 4
feet short), I am not going o worry about them...  As far as I can tell
from about two weeks of heavy research, this will not make a major
difference.  The return currents on the radials are highest close to the
antenna, and get lower as you go further out, so the effect of slightly
shortened radials "should" not be an issue.

It strikes me that a few shortened radials, while definitely making a
difference, will be so small a difference so as not to worry about.  I
do worry about the pattern distortion though, but am not smart enough
with EZNEC yet to be able to model the arrays, and one takes what one
can get...  In my case, I have been lucky so far...

I intend to lay out radials until I get only small changes in R for each
doubling of radials, as measured using an MFJ-259B...  I will install
the antenna and follow these steps:

1.  Take a R measurement.
3.  Take another R measurement.
4.  If difference between last to R measurements is something small,
then go to 6.
5.  Goto 2
6. End

As you can tell I used to program, and I find that it helps to formalize
the steps being taken.  In step 4, when I start approaching a less than
10% change, as I approach 36 Ohms, I will start thinking about stopping.
Once I get close to 36 Ohms...  I'm done with radials...

If for some reason I get lazy, I will put a lot of shortened radials in,
as opposed to a few longer radials.  Studies indicate that many shorter
radials are better than a few long ones.  This is caused by the return
currents being highest near the base of the antenna, so more radials are
more effective than a few long ones.  I will not get lazy though, I want
as perfect an array as possible for a ground mounted array, the thought
of elevating the array, and having 10 or so radials did cross my head,
but only for a moment...

I will be taking out my trusty RF Ammeter to look at each antenna after
the radials are in place...  I want to insure the same power in each
antenna.

If you have any thoughts on this, good, or bad, please let me know
sooner than later...  That goes for anyone looking at this...  I would
layout.

I purchased two miles of wire for the radial field...  :)

See:
and
http://www.antennasbyn6lf.com/files/antenna_ground_system_experiment_2.pdf

--
Thanks,
Dave
For Amateur Radio equipment reviews and setups see:
http://www.nk7z.net

On Sun, 2013-05-12 at 16:47 -0700, W. J. Karle wrote:
>
>
> Knowing that you are going with buried radials, I have a related
> question.
>
>
> It is difficult for me to determine, Dave, if the property is wide and
> deep enough for a radial system of many (~32) quarter wave radials.
>  Is it?  If not, what radial strategy are you planning?
>
>
> 73,
>
>
> Bill
>
>
>
>
>
>
>
>

<*>Attachment(s) from David Cole:

<*> 1 of 1 Photo(s) http://groups.yahoo.com/group/30MDG/attachments/folder/1396315328/item/list
<*> array context.jpg

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

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• Dave, Following on my recent message, the RF Exposure calculator that I use is the one from ARRL.  It is at  http://hintlink.com/power_density.htm Bill
Message 4 of 7 , May 16 6:07 PM
Dave,

Following on my recent message, the RF Exposure calculator that I use is the one from ARRL.  It is at

Bill

------------------------------------------------------------------------------------------------------
W. J. (Bill) Karle, VE4KZ
Amateur Radio Emergency Service -- Certified Emergency Coordinator

• Hi, Thank you! I found that one and ran the numbers, everything is contained within my yard, and behind a fence at acceptable levels!! :) I used 1500 W for 7
Message 5 of 7 , May 16 9:57 PM
Hi,

Thank you! I found that one and ran the numbers, everything is
contained within my yard, and behind a fence at acceptable levels!! :)
I used 1500 W for 7 MHz., and 3 db gain, and 200 for 10 MHz. at 6 db.
--
Thanks,
Dave
For Amateur Radio equipment reviews and setups see:
http://www.nk7z.net

On Thu, 2013-05-16 at 18:07 -0700, W. J. Karle wrote:
>
>
> Dave,
>
>
> Following on my recent message, the RF Exposure calculator that I use
> is the one from ARRL. It is at
>
>
>
> Bill
>
>
> ------------------------------------------------------------------------------------------------------
> W. J. (Bill) Karle, VE4KZ
> Amateur Radio Emergency Service -- Certified Emergency Coordinator
>
>
> ______________________________________________________________________
>
>
>
>
>
>
>
>
• Hi, Thank you! The rains have returned with a vengeance here for now... I expect a few more days of rain, (should make the ground soft for radial, and
Message 6 of 7 , May 16 10:00 PM
Hi,

Thank you! The rains have returned with a vengeance here for now... I
expect a few more days of rain, (should make the ground soft for radial,
and cabling), then I'll start the next phase, of getting Feed lines in
conduit, and radials down for Antenna #1. Once #1 is running fine, I'll
install #2. Same steps, and that should finish the 40 meter portion...
I am a bit worried about my GAP sitting just under 1.4 wave away... If
it gets it the way, I'll move it... :)
--
Thanks,
Dave
For Amateur Radio equipment reviews and setups see:
http://www.nk7z.net

On Thu, 2013-05-16 at 17:34 -0700, W. J. Karle wrote:
>
>
> Dave:
>
>
>
>
> The installation layout and your plan regarding when to stop laying
>
>
> Someone mentioned concerns about BCI/TVI to nearby neighbours but I
> imagine that should be less of a problem than heretofore since not too
> many receivers are operating with 7 and 10MHz IFs (or a harmonic
> thereof), although some do.
>
>
> I have not run the curves but I wonder if neighbors' RF exposure will
> be below the published limits.
>
>
> We all will be following your path to success. Good luck.
>
>
> 73,
>
>
> Bill
>
>
> ------------------------------------------------------------------------------------------------------
> W. J. (Bill) Karle, VE4KZ
> Amateur Radio Emergency Service -- Certified Emergency Coordinator
>
>
> ______________________________________________________________________
>
> From: David Cole <dave@...>
> To: 30MDG@yahoogroups.com
> Sent: Tuesday, May 14, 2013 9:39:01 AM
> Subject: Re: [30MDG] 30/40 Meter Arrays, Status [1 Attachment]
>
>
> Hello Bill,
>
> I got lucky... The lot is long and narrow relative to itself, close
> to
> a 5:1 ratio... The lot is about 300 feet long, and about 60 feet
> wide,
> so I can just get radials in place for both a 30 meter four square,
> and
> a 40 meter two element. Enclosed is a scaled map showing the antenna
> locations on the lot, and the radials needed, to scale. I have also
> added an image called "Array Context", showing the area for about 1/2
> mile around my home. As you can see, I am on the edge of a huge open
> area in the middle of a town... As I said, I got very lucky. My lot
> is
> defined by the "A", from Google.
>
> In the areas where the radials will be slightly short, (maybe 3 or 4
> feet short), I am not going o worry about them... As far as I can
> tell
> from about two weeks of heavy research, this will not make a major
> difference. The return currents on the radials are highest close to
> the
> antenna, and get lower as you go further out, so the effect of
> slightly
> shortened radials "should" not be an issue.
>
> It strikes me that a few shortened radials, while definitely making a
> difference, will be so small a difference so as not to worry about. I
> do worry about the pattern distortion though, but am not smart enough
> with EZNEC yet to be able to model the arrays, and one takes what one
> can get... In my case, I have been lucky so far...
>
> I intend to lay out radials until I get only small changes in R for
> each
> doubling of radials, as measured using an MFJ-259B... I will install
> the antenna and follow these steps:
>
> 1. Take a R measurement.
> 2. Double the radial count.
> 3. Take another R measurement.
> 4. If difference between last to R measurements is something small,
> then go to 6.
> 5. Goto 2
> 6. End
>
> As you can tell I used to program, and I find that it helps to
> formalize
> the steps being taken. In step 4, when I start approaching a less
> than
> 10% change, as I approach 36 Ohms, I will start thinking about
> stopping.
> Once I get close to 36 Ohms... I'm done with radials...
>
> If for some reason I get lazy, I will put a lot of shortened radials
> in,
> as opposed to a few longer radials. Studies indicate that many
> shorter
> radials are better than a few long ones. This is caused by the return
> currents being highest near the base of the antenna, so more radials
> are
> more effective than a few long ones. I will not get lazy though, I
> want
> as perfect an array as possible for a ground mounted array, the
> thought
> of elevating the array, and having 10 or so radials did cross my head,
> but only for a moment...
>
> I will be taking out my trusty RF Ammeter to look at each antenna
> after
> the radials are in place... I want to insure the same power in each
> antenna.
>
> If you have any thoughts on this, good, or bad, please let me know
> sooner than later... That goes for anyone looking at this... I would
> much rather change plans prior to radial layout, than post radial
> layout.
>
> I purchased two miles of wire for the radial field... :)
>
> See:
> and
> http://www.antennasbyn6lf.com/files/antenna_ground_system_experiment_2.pdf
>
>
> --
> Thanks,
> Dave
> For Amateur Radio equipment reviews and setups see:
> http://www.nk7z.net
>
>
>
> On Sun, 2013-05-12 at 16:47 -0700, W. J. Karle wrote:
> >
> >
> > Knowing that you are going with buried radials, I have a related
> > question.
> >
> >
> > It is difficult for me to determine, Dave, if the property is wide
> and
> > deep enough for a radial system of many (~32) quarter wave radials.
> > Is it? If not, what radial strategy are you planning?
> >
> >
> > 73,
> >
> >
> > Bill
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
> ------------------------------------
>
> Please join in with us on the 30 Meter Band. When in the shack use the
> 30 mtr digital Spots page made possible by Laurie VK3AMA
>
> http://hamspots.net/30mdg/
>
>
>
>