Engineers
 

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Engineers
 

"Reg Edwards" wrote in message
...
Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Engineers - Photo 16b.jpg (0/1)
 

On Tue, 8 Aug 2006 15:39:16 +0100, "Reg Edwards"
wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Hello Reg,

I haven't previously tried to attach a jpg file in this arena, but I'm going to
try. If my jpg file comes through, can you describe what it does and how it
works?

Walt, W2DU

Engineers - Photo 16b.jpg (0/1)
 

"Walter Maxwell" wrote in message
...
On Tue, 8 Aug 2006 15:39:16 +0100, "Reg Edwards"

wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Hello Reg,

I haven't previously tried to attach a jpg file in this arena, but I'm
going to
try. If my jpg file comes through, can you describe what it does and how
it
works?

Walt, W2DU

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank

Engineers - Photo 16b.jpg (0/1) - Photo 16a.jpg (0/1)
 

On Tue, 08 Aug 2006 16:39:13 GMT, "Frank's" wrote:

"Walter Maxwell" wrote in message
.. .
On Tue, 8 Aug 2006 15:39:16 +0100, "Reg Edwards"

wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Hello Reg,

I haven't previously tried to attach a jpg file in this arena, but I'm
going to
try. If my jpg file comes through, can you describe what it does and how
it
works?

Walt, W2DU

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank

Engineers - Photo 16b.jpg (0/1)
 

On Tue, 08 Aug 2006 16:39:13 GMT, "Frank's" wrote:

"Walter Maxwell" wrote in message
.. .
On Tue, 8 Aug 2006 15:39:16 +0100, "Reg Edwards"

wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Hello Reg,

I haven't previously tried to attach a jpg file in this arena, but I'm
going to
try. If my jpg file comes through, can you describe what it does and how
it
works?

Walt, W2DU

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank

Hi Frank,

I used the 'help' menu in Agent, but it doesn't seem to let me post an
attachment. Guess, like you said, it must be an NG rule that prevents it.
Anyhoo, jist fertheleovit, I'm going to email you the jpg file fyi.

Walt, W2DU

Engineers - Photo 16b.jpg (0/1)
 

On Tue, 08 Aug 2006 16:39:13 GMT, "Frank's" wrote:

"Walter Maxwell" wrote in message

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank

Frank, I tried to send the jpg file to you via email, but the server rejects
your address. Can you email me so I can have your correct address?

Walt

Engineers - Photo 16b.jpg (0/1)
 

Hi Frank,

I used the 'help' menu in Agent, but it doesn't seem to let me post an
attachment. Guess, like you said, it must be an NG rule that prevents it.
Anyhoo, jist fertheleovit, I'm going to email you the jpg file fyi.

Walt, W2DU

Yes Walt, I got a message in the send window that said the NG rejected it.
Don't forget to removed the "nospam." from my e-mail address, also note
the period after the "m"., which must also be removed.

Will be curious to see the jpeg, but doubt I will be smart enough to figure
it out.

Thanks,

Frank

Engineers
 

On Tue, 8 Aug 2006 15:39:16 +0100, "Reg Edwards"
wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

Hi Reggie,

You prove you can write in English, but equally proven is that this
post is as obscure as reading Beowulf. However, it is equally notable
that most English speakers have some of the poorest grammar:
These days, there are mostly Tom's, Dick's and Harry's!
where possessive case substitutes for plurals.

Is this the standard troll, or whining? Do you somehow feel
disappointed that Engineers don't create art? Has your esteem for
British luminaries suddenly dimmed by their lack of imagination?

I for one cannot imagine Bill Thomson sitting on a Parisian sidewalk
doing chalk copies of renaissance art - unless he was anticipating
your holiday so as to wing that chalk off your noggin.

Or perhaps you pine for the lost opportunity of Auguste Rodin
sculpting Pascal code out of marble. Whoops! A frog there. Perhaps
a Tom Gainsborough sloshing the paint to rummage up an astable
multivibrator.

Oh for the days when they were mostly Toms, Bills, and Augustes....
and Marcels - "À la Recherche du Temps Perdu" Now there's a French
sleeping pill no engineer would copy.

73's
Richard Clark, KB7QHC

Engineers - Photo 16b.jpg (0/1)
 

Frank's wrote:
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Yep, this newsgroup was chartered as ASCII only.
--
73, Cecil http://www.qsl.net/w5dxp

Engineers
 

On Tue, 8 Aug 2006 15:39:16 +0100, Reg Edwards wrote:
Any Tom, Dick and Harry can copy and build a circuit out of a book.

I wish you would cease the TROLLing whenever you get bored... I know
there are soooooo many easy foils here for your outbursts. But, just
because a thing is do-able does not mean it should be done.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http//jonz.net/ng.htm

Engineers - Photo 16b.jpg (0/1)
 

On Tue, 08 Aug 2006 16:39:13 GMT, "Frank's"
wrote:
[snip]

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank

Walt was nice enough to send me the graphic and, so others can see it,
I've placed it on my web page for your viewing pleasure.

http://k6mhe.com/sub/w2du_engineering.jpg

Note: This will available for about 30 days.

Danny, K6MHE

Engineers - Photo 16b.jpg (0/1) - Photo 16a.jpg (0/1)
 

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank



Walt was nice enough to send me the graphic and, so others can see it,
I've placed it on my web page for your viewing pleasure.

http://k6mhe.com/sub/w2du_engineering.jpg

Note: This will available for about 30 days.

Danny, K6MHE

Engineers - Photo 16b.jpg (0/1)
 

On Tue, 08 Aug 2006 14:34:50 -0700, Dan Richardson
wrote:

Walt was nice enough to send me the graphic and, so others can see it,
I've placed it on my web page for your viewing pleasure.

http://k6mhe.com/sub/w2du_engineering.jpg

"There cannot be a greater mistake than that of looking superciliously
upon practical applications of science. The life and soul of science
is its practical application."
- Bill Thomson

Engineers
 

Ya, but...5 out of 4 engineers are dyslexic...

Scott
N0EDV

Reg Edwards wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Engineers - Photo 16b.jpg (0/1)
 

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When
this
is completed I can try some high frequency models.

Frank
=========================================

Frank, don't forget to use a 1/4-wave vertical when calculating
efficiency.

I assume you always include the power in the ground wave in the total
power radiated when calculating efficiency.

I think radial length intervals of 0.5 metres will be OK for 100 or
more radials.
----
Reg.

Engineers - Photo 16b.jpg (0/1) - Photo 16a.jpg (0/1)
 

"Dan Richardson" wrote in message
...


Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank



Walt was nice enough to send me the graphic and, so others can see it,
I've placed it on my web page for your viewing pleasure.

http://k6mhe.com/sub/w2du_engineering.jpg

Note: This will available for about 30 days.

Danny, K6MHE


At first glance I thought of the multiplexed FM broadcast antennas on One
Shell Plaza in Houston 33 years ago..

73
H.
NQ5H

Engineers - Photo 16b.jpg (0/1)
 

I used the 'help' menu in Agent, but it doesn't seem to let me post an
attachment.

In order to post a jpg you would need to essentially convert it to
text. I think a program called uuencode does it.
Then it comes out looking like 15,000 lines of garbage to anyone
reading the articles here. It would make you a lot of enemies faster
than calling CQ on 14336.

Put it another way - the rec.radio newsgroups are text only.

Rick K2XT

Engineers - Photo 16b.jpg (0/1) - Photo 16a.jpg (0/1)
 

"Dan Richardson" wrote in message
...


Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank



Walt was nice enough to send me the graphic and, so others can see it,
I've placed it on my web page for your viewing pleasure.

http://k6mhe.com/sub/w2du_engineering.jpg

Note: This will available for about 30 days.

Danny, K6MHE

Thanks Danny,

Frank

Engineers
 

Scott wrote:

Ya, but...5 out of 4 engineers are dyslexic...


Eye dish garee wthi ttha marekr!

/s/ DD, + froutie yeers na nerieng.

Engineers - Photo 16b.jpg (0/1)
 

Frank, don't forget to use a 1/4-wave vertical when calculating
efficiency.

I assume you always include the power in the ground wave in the total
power radiated when calculating efficiency.

I think radial length intervals of 0.5 metres will be OK for 100 or
more radials.

Reg,

I have always used the 1/4 wave vertical to calculate efficiency.
Most of my calculations do not include the surface wave. The problem
with including the surface wave is that it is computed over a cylindrical
surface at x meters from the antenna. Technically not a surface, but
rather a vertical line in cylindrical coordinates. The surface is implied
due to the expected symmetry of radiation. In my calculations I have
taken "x" as 200 m, so as to ensure the result is in the far-field at 8 MHz
(nominal 5 wavelengths). I compute the field at 1 m intervals, in the "z"
direction to 200 m. To include the total field I would have to allow z
to approach infinity. Taking these data from the NEC output text file, I
import it to Excel. In Excel I compute the radial distance and elevation
angle to the source. Since my increments are in steps of one meter
I can only approximate integral degree points; removing those points
far from integral degrees. I could employ
linear interpolation, but the field intensity variation is relatively
smooth,
and adds no discernable ripple to the radiation pattern. I then
normalize these data to 1 m to match the spherical data for the
sky wave pattern. At 45 degrees elevation there is very little
ground wave effects, I can then combine the two normalized
sets of data, and numerically integrate over a hemispherical surface.

Sorry to bore you with these details, but just to give an idea of
the tedious steps involved in including the surface wave. To compute
the total radiated sky wave involves a simple command in NEC.
Just the same I can compute the total radiated power at 0.5 m
and 10 m radial lengths as a comparison. At every 0.5 m it would
drive me nuts.

Attempting to model a 100 radial system I continually run into
road blocks. At one point I had a complex matrix with 3.6
million entries. Still I think I have a viable model that needs
just a little refinement. Due to the rotational symmetry of the
structure I can employ methods that greatly reduce run time. The
model that should work will consist of thirty-three 10 cm
radials. At the end of these short radials I connect three 9.9 m
radials for a total of 99 radials. If I run into problems I may
have to reduce the segmentation to 25 cm. What is interesting,
in my preliminary results, is that there is only a 2% improvement
in sky wave total radiated power with 120 radials over 36 radials.

Frank

Engineers - Photo 16b.jpg (0/1)
 

The hell you say. Richard's jpg of VSWR came through quite nicely.

Jim



Put it another way - the rec.radio newsgroups are text only.

Rick K2XT

Engineers - Photo 16b.jpg (0/1)
 

RST Engineering wrote:
The hell you say. Richard's jpg of VSWR came through quite nicely.

Not on my news-server. It appears that some ISP's block
binaries and some do not.
--
73, Cecil http://www.qsl.net/w5dxp

Engineers - Photo 16b.jpg (0/1)
 

Cecil Moore wrote:
RST Engineering wrote:
The hell you say. Richard's jpg of VSWR came through quite nicely.

Not on my news-server. It appears that some ISP's block
binaries and some do not.
--
73, Cecil http://www.qsl.net/w5dxp

Few news servers will handle binaries.

Almost every news reader will automaticaly ASCII encode a binary on
transmission and decode it upon receipt.

That's a bit simplified, but basically how it works.

--
Jim Pennino

Remove .spam.sux to reply.

Engineers - Photo 16b.jpg (0/1)
 

Rick wrote:



In order to post a jpg you would need to essentially convert it to
text. I think a program called uuencode does it.
Then it comes out looking like 15,000 lines of garbage to anyone
reading the articles here. It would make you a lot of enemies faster
than calling CQ on 14336.

Problem with the 336 crowd is that they almost never check before _they_
transmit up or down the band. And if they do check, they wait about 500
milliseconds before they figure the freq is clear. They have lots of
enemies themselves, myself being one. They have a very poor reputation
on 20.

tom
K0TAR

Engineers - Photo 16b.jpg (0/1)
 

"Frank's" wrote
Reg,

I have always used the 1/4 wave vertical to calculate efficiency.
Most of my calculations do not include the surface wave. The
problem
with including the surface wave is that it is computed over a
cylindrical
surface at x meters from the antenna. Technically not a surface,
but
rather a vertical line in cylindrical coordinates. The surface is
implied
due to the expected symmetry of radiation. In my calculations I
have
taken "x" as 200 m, so as to ensure the result is in the far-field
at 8 MHz
(nominal 5 wavelengths). I compute the field at 1 m intervals, in
the "z"
direction to 200 m. To include the total field I would have to
allow z
to approach infinity. Taking these data from the NEC output text
file, I
import it to Excel. In Excel I compute the radial distance and
elevation
angle to the source. Since my increments are in steps of one meter
I can only approximate integral degree points; removing those points
far from integral degrees. I could employ
linear interpolation, but the field intensity variation is
relatively
smooth,
and adds no discernable ripple to the radiation pattern. I then
normalize these data to 1 m to match the spherical data for the
sky wave pattern. At 45 degrees elevation there is very little
ground wave effects, I can then combine the two normalized
sets of data, and numerically integrate over a hemispherical
surface.

Sorry to bore you with these details, but just to give an idea of
the tedious steps involved in including the surface wave. To
compute
the total radiated sky wave involves a simple command in NEC.
Just the same I can compute the total radiated power at 0.5 m
and 10 m radial lengths as a comparison. At every 0.5 m it would
drive me nuts.

Attempting to model a 100 radial system I continually run into
road blocks. At one point I had a complex matrix with 3.6
million entries. Still I think I have a viable model that needs
just a little refinement. Due to the rotational symmetry of the
structure I can employ methods that greatly reduce run time. The
model that should work will consist of thirty-three 10 cm
radials. At the end of these short radials I connect three 9.9 m
radials for a total of 99 radials. If I run into problems I may
have to reduce the segmentation to 25 cm. What is interesting,
in my preliminary results, is that there is only a 2% improvement
in sky wave total radiated power with 120 radials over 36 radials.

Frank
======================================

Frank,

Radiating efficiency is of secondary importance. It does not change
very much with length of radials except at very short lengths.

If computing efficiency involves great labour then do it at infrequent
intervals.

What IS important is the input impedance of a collection of N radials
versus length, frequency and ground characteristics. From which
efficiency can be calculated if required.

I know not, and do not need to know, the details of how you use NEC4.
I think it is safe to assume NEC4 provides reasonably correct answers.

After all, the primary purpose of NEC4 is to generate radiation
patterns from highly suspect input data. And I'm sure approximations
are involved somewhere. When a camel is designed by several
committees in succession, who knows how many humps can appear?

I am about to delete all contents of these threads. I look forward to
seeing a message from "Frank's".
----
Reg, G4FGQ.

Engineers - Photo 16b.jpg (0/1)
 

"Frank's" wrote
What is interesting, in my preliminary results, is that there is
only a 2% improvement in sky wave total radiated power with
120 radials over 36
=====================================
Frank,

If what you are saying is that efficiency is the same for both 36 and
120 radials, then, at least at 8 MHz, B,L&E's findings for LF do not
apply at HF.

Amateurs do not use LF. They use HF.
----
Reg.

Engineers - Photo 16b.jpg (0/1)
 

=====================================
Frank,

If what you are saying is that efficiency is the same for both 36 and
120 radials, then, at least at 8 MHz, B,L&E's findings for LF do not
apply at HF.

Amateurs do not use LF. They use HF.
----
Reg.

You could well be correct Reg. I will get back to B, L & E's paper
and see if I can obtain some correlation between the measurements,
and calculated results At the moment I see 2.5% improvement
between 36 and 99 radials at 8 MHz.

What has also been throwing me off track for a while
was the fact that the input impedance of the 99 radial antenna was less
than than the expected radiation resistance of 36 ohms.
I used this assumption on all my previous
results, so they may have some errors. Applying this technique to the
99 radial antenna would lead to a real resistance component of less than
zero.
Cebik's analysis of buried radial monopoles (www.cebik.com) also
corroborate my findings. Based on the total radiated power, (40% of input)
including surface wave, the radiation resistance is closer to 14 ohms.


Frank

Engineers - Photo 16b.jpg (0/1)
 

What about the Lowfers in the 135 KHz range? I've hear rumors of hams
using those LF frequencies...

Scott



Reg Edwards wrote:

"Frank's" wrote
What is interesting, in my preliminary results, is that there is
only a 2% improvement in sky wave total radiated power with
120 radials over 36

=====================================
Frank,

If what you are saying is that efficiency is the same for both 36 and
120 radials, then, at least at 8 MHz, B,L&E's findings for LF do not
apply at HF.

Amateurs do not use LF. They use HF.
----
Reg.

Engineers - Photo 16b.jpg (0/1)
 

"Reg Edwards" wrote:

If what you are saying is that efficiency is the same for both
36 and 120 radials, then, at least at 8 MHz, B,L&E's findings
for LF do not apply at HF.
__________

The BL&E measurements were made at 3 MHz.

Engineers - Photo 16b.jpg (0/1)
 

Reg,

The K3LC study is probably the most definitive look at radials since BL&E.
The following URL takes you to the *.pdf file wherein they evaluate radials
under various soil conditions, on 160/80/40 meters. They used NEC-4 for
their study. This is the study that resulted in the "radial optimization"
formula that several of us have referred to.

http://www.ncjweb.com/k3lcmaxgainradials.pdf

Since this is all NEC-4...it should compliment what you are having Frank do.

Here is the formula info:

(This formula is from both QST and Low Band Dx'ers Handbook by Devoldre)

Obviously a ton of short radials does not equal a ton of long radials, but
it can get you really close. See the articles for limitations of the
formula. Don't use the formula like this: Gee, I only have 200 feet for
radial wire. It will give you the right
answer....but...when you only use so little total wire, your losses will be
quite a bit worse than the 0.5 to 1 dB that was the goal of the studies.

The formula goes like this: (wire length in meters)

N = ((2*PI*W)^0.5)/1.2

N equals the square root of the quantity (2*PI*WireLength) divided by 1.2

Where N = number of radials

Where W = length in meters of available wire to make the radials

Length of radials = W/N

and the constant 1.2 is the tip separation in meters to produce the proper
density on 80m ..this would be twice the density one needs for 160m and half
what is needed on 40m. The value for minimum tip separation is simply .015
wavelength. So if you calculate a full wavelength for the freq in use,
multiply it
by .015 and that gives you the value for tip separation in the formula
above. For 80m it is 1.2 meters

Example:

You have 500 meters (about 1640 feet) of radial wire available for your 80m
vertical. How many and how long should the radials be:

46 radials, 10.8 meters (35.6 feet) will produce the lowest possible loss
for this amount of available wire.

This is a simple formula for how many radials to put down if you have
"only so much wire". These days with copper prices through the roof, it pays
to be economical and still stay within 0.5 to 1 dB of "what's best".

73,

....hasan, N0AN

"Reg Edwards" wrote in message
...
"Frank's" wrote
What is interesting, in my preliminary results, is that there is
only a 2% improvement in sky wave total radiated power with
120 radials over 36
=====================================
Frank,

If what you are saying is that efficiency is the same for both 36 and
120 radials, then, at least at 8 MHz, B,L&E's findings for LF do not
apply at HF.

Amateurs do not use LF. They use HF.
----
Reg.

Engineers - Photo 16b.jpg (0/1)
 

Guys:

FYI...

Walt is correct. This "rec.radio.amateur.antenna" USENET NG (aka "rraa") and
many other newsgroups redact any graphics, attachments or inserts associated
with NG posts, allowing only text to be posted. This practice is followed
of course in the interests of both memory and bandwidth conservation at the
"free" USENET servers. No one running USENET servers makes money!

However, a number of years ago a special USENET newsgroup was set up by
USENET volunteers in the "alt.binaries" area, to be used for short term
postings of graphics content related to electronics such as schematics,
etc...

There are a couple of minor problems associated with this approach. (1) For
one, the biggest problem is that not all ISPs actually carry the
"alt.binaries" groups due to either, server memory limitations or, because
several (many?) alt.binaries groups carry pornograhic graphics. (2) The
second small "problem" is that, again for reasons of memory conservation,
the "turnover" of postings on those graphics/binaries groups is fairly high.
That is postings are cycled through fairly quickly, usually with
availability of only a week or so. And so one should surf on over to the
alt.binaries group quickly to view or download any desired postings.

All that said however, ya'll should find that
"alt.binaries.schematics.electronics" (aka "abse") is a good place to post
drawings, schematics, block diagrams, photos and other graphics content
related to electronics and antennas, etc.

The usual procedure in the "electronics" groups such as
"sci.electronics.design" (aka "sed") is to mention that the
graphics/schematic referred to in your postings, has been posted on the
other NG that accepts graphics/binaries.

For example lots of the folks who hang out and discourse on:
"sci.electronics.design" (aka "sed") post their schematics, block diagrams,
photos, etc... to "alt.binaries.schematics.electronics" (aka "abse").

There is no reason why the denziens of "rraa" cannot post their antenna
graphics on "abse".

Sign up for abse and... Go for it... just do it!

Hope this helps. :-)

--
Pete k1po
Indialantic By-the-Sea, FL

"Walter Maxwell" wrote in message
...
On Tue, 08 Aug 2006 16:39:13 GMT, "Frank's"
wrote:

"Walter Maxwell" wrote in message
. ..
On Tue, 8 Aug 2006 15:39:16 +0100, "Reg Edwards"

wrote:

Any Tom, Dick and Harry can copy and build a circuit out of a book.

But it takes a top-class engineer just to look at a strange circuit
and describe what it does, how it works.

These days, there are mostly Tom's, Dick's and Harry's!
====================================
Amendment -

For "circuit" read "antenna".

"Tom's, Dick's and Harry's" has replaced "old wives". ;o) ;o)

====================================

Hello Reg,

I haven't previously tried to attach a jpg file in this arena, but I'm
going to
try. If my jpg file comes through, can you describe what it does and how
it
works?

Walt, W2DU

Rats, now you have me intrigued Walt. Too bad the pic did not work.
Just tried to post a picture, but it seems there is a filter on the NG to
prevent such postings.

Reg, have made a lot of progress in developing a NEC 4 model
of a 100 radial system. Just have to iron out a few bugs. When this
is completed I can try some high frequency models.

Frank

Hi Frank,

I used the 'help' menu in Agent, but it doesn't seem to let me post an
attachment. Guess, like you said, it must be an NG rule that prevents it.
Anyhoo, jist fertheleovit, I'm going to email you the jpg file fyi.

Walt, W2DU

Engineers - Photo 16b.jpg (0/1)
 

"hasan schiers" wrote in message
...
Reg,

The K3LC study is probably the most definitive look at radials
since BL&E.
The following URL takes you to the *.pdf file wherein they evaluate
radials
under various soil conditions, on 160/80/40 meters. They used NEC-4
for
their study. This is the study that resulted in the "radial
optimization"
formula that several of us have referred to.

http://www.ncjweb.com/k3lcmaxgainradials.pdf

Since this is all NEC-4...it should compliment what you are having
Frank do.

Here is the formula info:

(This formula is from both QST and Low Band Dx'ers Handbook by
Devoldre)

Obviously a ton of short radials does not equal a ton of long
radials, but
it can get you really close. See the articles for limitations of the
formula. Don't use the formula like this: Gee, I only have 200 feet
for
radial wire. It will give you the right
answer....but...when you only use so little total wire, your losses
will be
quite a bit worse than the 0.5 to 1 dB that was the goal of the
studies.

The formula goes like this: (wire length in meters)

N = ((2*PI*W)^0.5)/1.2

N equals the square root of the quantity (2*PI*WireLength) divided
by 1.2

Where N = number of radials

Where W = length in meters of available wire to make the radials

Length of radials = W/N

and the constant 1.2 is the tip separation in meters to produce the
proper
density on 80m ..this would be twice the density one needs for 160m
and half
what is needed on 40m. The value for minimum tip separation is
simply .015
wavelength. So if you calculate a full wavelength for the freq in
use,
multiply it
by .015 and that gives you the value for tip separation in the
formula
above. For 80m it is 1.2 meters

Example:

You have 500 meters (about 1640 feet) of radial wire available for
your 80m
vertical. How many and how long should the radials be:

46 radials, 10.8 meters (35.6 feet) will produce the lowest possible
loss
for this amount of available wire.

This is a simple formula for how many radials to put down if you
have
"only so much wire". These days with copper prices through the roof,
it pays
to be economical and still stay within 0.5 to 1 dB of "what's
best".

73,

...hasan, N0AN
========================================
Hasan,

Thanks very much for the formula of which I was entirely unaware. I
will study it.

I notice that it disregards resistivity and permittivity of the ground
under under the antenna which, obviously, ought be taken into account
even when only crudely known.

There's a great difference between a soil resistivity of 25 and 5000
ohm-metres.

This is similar to BL&E who simply state that if the length and number
of radials are greater than certain amounts then soil characteristics
don't matter.
----
Reg.

Engineers - Photo 16b.jpg (0/1)
 

Hi Reg,

Notice that the purpose of the formula is to get the maximum performance
from a finite length of available wire. So it doesn't make much difference
what the ground characteristics are..the goal is to put down enough and the
right length so that the ground characteristics don't matter any more.

For more detail, go the the url I listed, as it shows the effects of various
ground characteristics:

http://www.ncjweb.com/k3lcmaxgainradials.pdf

With this data, the generic formula and your own work, something synthetic
could result that is even better than your most recent efforts. It is a VERY
interesting subject to those of us using ground mounted verticals.

73,

....hasan, N0AN

"Reg Edwards" wrote in message
...

========================================
Hasan,

Thanks very much for the formula of which I was entirely unaware. I
will study it.

I notice that it disregards resistivity and permittivity of the ground
under under the antenna which, obviously, ought be taken into account
even when only crudely known.

There's a great difference between a soil resistivity of 25 and 5000
ohm-metres.

This is similar to BL&E who simply state that if the length and number
of radials are greater than certain amounts then soil characteristics
don't matter.
----
Reg.