On Tue, 1 Feb 2005 11:41:50 -0500, "Jack Painter"
wrote:

Thanks Cecil. It probably is a power-sink when xmit. The antenna was
originally set up as a receive-only antenna, and you should hear the
difference in volume when the grounded side of the Balun is off/on the
ground rod. Audible increase (for DX purposes, where a couple of S-units is
a lot, hi). I'll try the radials, and disconnect the shorting ground, and
see if this improves things a little. I never heard anyone mention making a
"vee" dipole antenna (from the ground-up), is that a NVIS?

Jack



I would think it would be NVIS. A lazy Vee ( horizontal wires) is
directional going from the point through the midpoint between the two
ends.

If it is directional horizontal, it must be directional pointed strait
up.


--
73 for now
Buck
N4PGW

"Buck" wrote
"Jack Painter"
wrote:

Thanks Cecil. It probably is a power-sink when xmit. The antenna was
originally set up as a receive-only antenna, and you should hear the
difference in volume when the grounded side of the Balun is off/on the
ground rod. Audible increase (for DX purposes, where a couple of S-units
is
a lot, hi). I'll try the radials, and disconnect the shorting ground, and
see if this improves things a little. I never heard anyone mention
making a
"vee" dipole antenna (from the ground-up), is that a NVIS?

Jack


I would think it would be NVIS. A lazy Vee ( horizontal wires) is
directional going from the point through the midpoint between the two
ends.

If it is directional horizontal, it must be directional pointed strait
up.

--
73 for now
Buck
N4PGW


Adding a single radial under 45 degree random wires did not have a
noticeable effect on 2182 performance under the midday sun. 100 miles was
it's maximum and barely readable (both ways) from the one station I talked
to. Even if I did configure it for NVIS, that would make a totally useless
daytime antenna for MF, with all of it's energy being absorbed. The
Canadian stations certainly do well, being loud and clear from Halifax, St
Johns, Placentia, Labrador, St Anthony, all the way to the Mid-Atlantic. I
guess a vertical or high elevation 1/2 wave dipole are the only solutions
for daytime success there. Maybe a job for the super-Isotron, hi, hi. But
seriously, I might try a much longer wire, something close to 1/2 wave, with
a feedpoint-choke but no Balun.

73,
Jack Painter
Virginia Beach, Virginia

Ian Jackson wrote:
Cecil Moore writes:
A balanced-V would not have very much vertically polarized
radiation and thus would probably be an NVIS.

Vee antennas (inverted or not) tend to produce quite a lot of vertically
polarised radiation off the ends. Horizontal broadside, of course.
Ian.

Sorry, I left out a couple of words. Should have been
"A balanced-V would not have very much vertically polarized
low angle radiation and thus would probably be an NVIS."
--
73, Cecil http://www.qsl.net/w5dxp


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups
---= East/West-Coast Server Farms - Total Privacy via Encryption =---

Cecil Moore wrote:
Buck wrote:

Cecil Moore wrote:

EZNEC agrees. With four radials one foot above ground the gain
is -0.53 dBi. With one radial one foot above ground the gain
is -1.62 dBi in the direction of the one radial and - 6 dBi
in the opposite direction.


How does it rate it with that one radial buried in the ground as in
the OP rather than above the ground?


I don't have NEC-4 so I can't bury radials. Perhaps Roy will
do the honors. Incidentally, the above simulation was done
for a 33 ft vertical with 33 ft radials on 40m.

I've been extremely busy lately, but found a few minutes to run this.

This is for a 33 foot vertical with 33' ground wires buried 6 inches
deep. The model was run with EZNEC/4 using the NEC-4 calculating engine.
All are for average ground, and the gains are at the elevation angle
where gain is the maximum -- 26 degrees in all cases.

With one radial, the gain in the direction of the radial is -5.94 dBi,
-6.7 dBi in the opposite direction. It's interesting to see how much
difference it makes to have the radial just a foot above the ground, as
Cecil modeled, rather than six inches below. When the radial is above
the ground, the current distribution looks pretty much the same as the
vertical wire's. So it contributes significantly to the pattern. But
when buried, the current decays rapidly in an exponential-looking
fashion, so it doesn't contribute much to the radiation.

With one radial, the gain at right angles to the radial wire is -6.49 dBi.

With two radials, the gain in line with the radials is -4.33 dBi, and at
right angles essentially the same, -4.58 dBi.

With four radials, the gain is -2.95 dBi essentially in all directions.

With 8 radials, the gain is -1.79 dBi. This is just about what you get
in the favored direction with a single radial elevated one foot.
According to NEC-4, anyway. These would be some interesting experiments
to do with a real antenna.

And, running EZNEC using MININEC-type ground gives the gain you'd get
with a perfect radial system -- -0.02 dBi.

Roy Lewallen, W7EL

On Sat, 05 Feb 2005 23:32:55 -0800, Roy Lewallen
wrote:

Cecil Moore wrote:
Cecil Moore wrote:

EZNEC agrees. With four radials one foot above ground the gain
is -0.53 dBi. With one radial one foot above ground the gain
is -1.62 dBi in the direction of the one radial and - 6 dBi
in the opposite direction.
snip

This is for a 33 foot vertical with 33' ground wires buried 6 inches
deep. The model was run with EZNEC/4 using the NEC-4 calculating engine.
All are for average ground, and the gains are at the elevation angle
where gain is the maximum -- 26 degrees in all cases.

With one radial, the gain in the direction of the radial is -5.94 dBi,
-6.7 dBi in the opposite direction. It's interesting to see how much
difference it makes to have the radial just a foot above the ground, as
Cecil modeled, rather than six inches below. When the radial is above
the ground, the current distribution looks pretty much the same as the
vertical wire's. So it contributes significantly to the pattern. But
when buried, the current decays rapidly in an exponential-looking
fashion, so it doesn't contribute much to the radiation.

With one radial, the gain at right angles to the radial wire is -6.49 dBi.

With two radials, the gain in line with the radials is -4.33 dBi, and at
right angles essentially the same, -4.58 dBi.

With four radials, the gain is -2.95 dBi essentially in all directions.

With 8 radials, the gain is -1.79 dBi. This is just about what you get
in the favored direction with a single radial elevated one foot.
According to NEC-4, anyway. These would be some interesting experiments
to do with a real antenna.

And, running EZNEC using MININEC-type ground gives the gain you'd get
with a perfect radial system -- -0.02 dBi.

Roy Lewallen, W7EL


If I read this correctly, the more above ground radials (to a point),
the better. Until one gets to 8 radials, there is a significant drop
in antenna loss.

How do the gains/losses change when the radials are disproportionate?
i.e., you have been working with essentially a 40 meter vertical with
40 meter radials. What if I were to place a 20 meter vertical (16
foot for example) on that 33 foot radial system vs placing a 20 meter
vertical on the same 8 radials 16 foot long?

One of the things I would like to have for a multiband vertical is the
separate elements using GAP technology or just using a common feed
point as seen in some of the handbooks.


Thanks for all the info. I have a eznic and the ARRL version, but
there is something that isn't registering with me when using it.
Sometimes there are things I just can't seem to learn unless someone
shows me what i am doing wrong or missing.

Buck
N4PGW

--
73 for now
Buck
N4PGW

Buck wrote:

If I read this correctly, the more above ground radials (to a point),
the better. Until one gets to 8 radials, there is a significant drop
in antenna loss.

Nope, you didn't. My analysis was for buried, not above ground, radials.
And the loss increases, rather than drops, as the number increases. This
has been well known since at least 1937.

How do the gains/losses change when the radials are disproportionate?
i.e., you have been working with essentially a 40 meter vertical with
40 meter radials. What if I were to place a 20 meter vertical (16
foot for example) on that 33 foot radial system vs placing a 20 meter
vertical on the same 8 radials 16 foot long?

There are an infinite number of such questions, each with its own
answer. But a little research will show that the difference between 16
and 33 foot radials will make little difference on either 40 or 20
meters. There's been a lot posted on this newsgroup in the past about
ground radial systems -- you'll find the answers to many of your
questions by using groups.google.com for a search.


One of the things I would like to have for a multiband vertical is the
separate elements using GAP technology or just using a common feed
point as seen in some of the handbooks.

You really want to use a lossy piece of coax to load your antenna as the
GAP does instead of a more efficient method? Why? Fanned wires with a
common feed point will be more efficient. If you bury the radials, you
need only one ground system -- 8 or so radials will get you within a
couple of dB of a perfect system.


Thanks for all the info. I have a eznic and the ARRL version, but
there is something that isn't registering with me when using it.
Sometimes there are things I just can't seem to learn unless someone
shows me what i am doing wrong or missing.

I've heard many good comments about the ARRL on-line course in antenna
modeling. You might consider it.

Roy Lewallen, W7EL

On Sun, 06 Feb 2005 15:29:04 -0800, Roy Lewallen
wrote:

Nope, you didn't. My analysis was for buried, not above ground, radials.
And the loss increases, rather than drops, as the number increases. This
has been well known since at least 1937.


Thanks for the correction. As a Novice I learned that underground
radials were better than above ground radials. I couldn't be sure
which you were using so I re-iterated it to be sure.

How do the gains/losses change when the radials are disproportionate?
i.e., you have been working with essentially a 40 meter vertical with
40 meter radials. What if I were to place a 20 meter vertical (16
foot for example) on that 33 foot radial system vs placing a 20 meter
vertical on the same 8 radials 16 foot long?

you'll find the answers to many of your
questions by using groups.google.com for a search.

Thanks, I'll do that.



You really want to use a lossy piece of coax to load your antenna as the
GAP does instead of a more efficient method? Why? Fanned wires with a
common feed point will be more efficient. If you bury the radials, you
need only one ground system -- 8 or so radials will get you within a
couple of dB of a perfect system.

I didn't clarify myself, but the gap technology (I should have used
lower case) isn't necessarily the same as the GAP brand. I couldn't
find the book I have it in, but it is where a wire resonant on a
particular frequency brought close to another antenna will match the
system and radiate efficiently (I don't know how efficiently.) (this
is an oversimplification of what I am describing.)

I've heard many good comments about the ARRL on-line course in antenna
modeling. You might consider it.
I'll look into it. I understand a lot of what I am doing, but
something isn't working. I think it is one of those things that
someone needs to walk me through one time looking over my shoulder and
I'll get through it. Maybe it will just come to me one day.
Sometimes these things happen.

Thanks again.

Buck
--
73 for now
Buck
N4PGW

Buck wrote:
. . .
I didn't clarify myself, but the gap technology (I should have used
lower case) isn't necessarily the same as the GAP brand. I couldn't
find the book I have it in, but it is where a wire resonant on a
particular frequency brought close to another antenna will match the
system and radiate efficiently (I don't know how efficiently.) (this
is an oversimplification of what I am describing.)
. . .

That sounds like the method patented in 1996 by Gary Breed, K9AY (U.S.
patent #5,489,914). He allowed the patent to expire rather than renewing
it, so it's now in the public domain.

See
http://patft.uspto.gov/netacgi/nph-P...y+AND+IN/breed

(You'll probably have to paste that back together. Or just go to
http://www.uspto.gov and look it up by patent number.)

Roy Lewallen, W7EL

Buck wrote:
On Sun, 06 Feb 2005 15:29:04 -0800, Roy Lewallen
wrote:

Nope, you didn't. My analysis was for buried, not above ground,
radials.
And the loss increases, rather than drops, as the number increases.
This
has been well known since at least 1937.

This has me confused...I must be missing something...I checked the
previous
posts, but still doesn't make sense to me...Seems the ground losses
would
decrease as the number of radials increase....Thats what your model
showed.
I thought anyway....


Thanks for the correction. As a Novice I learned that underground
radials were better than above ground radials. I couldn't be sure
which you were using so I re-iterated it to be sure.

For a given radial, above ground is better than in ground. But it has
to
be resonant. In that case, you are running a very low ground plane.
If it's just one radial, it should radiate as much as the vertical
element. In that case, it's more of a perverted dipole, than a ground
plane. A true ground plane really needs at least two radials to get a
fairly unlopsided omni pattern. Three radials are better.
If you use 120 radials on medium ground as a benchmark, any height
above
ground will reduce the number of radials required to equal the same
degree of loss. But once the radials are elevated, they must be tuned.
Radials on or in the ground do not need to be resonant.
If you ran a vertical, and can only use a very few radials, having them
tuned and a bit off the ground is better than the same in the ground.
Of course, the YL will probably want to strangle you with one, the
first
time she trips over one...But some run them around the lower frames of
houses, wood fences, etc...
One thing....It's not a magic wand to suddenly make low 4 radials a dx
buster...At 1/8 wave up, it takes appx 60 radials to equal 120 on the
ground. On 40m, thats 16 ft or so... At 2 ft off the ground, you still
probably need maybe 90? radials to equal the 120 on the ground.
So you have to consider that, when you run 4 radials at 2 ft, and don't
brown the food in every direction. It is a bit better than 4 in the
ground though, and Roy's model pretty much agreed...I think anyway...:/
MK

Roy, it is a mistake to consider one element of a radiating system as being
distinct from another. Reflectors and directors do not operate
independently of the embedded 1/2-wave dipole. And, for example, the
universally-made error of treating radiation from the feedline as being
independent of that from the antenna is a serious matter. Aggravated by
ignoring the choke location if there is one.

Similar (greatly prolonged) educational mistakes lead to serious
misunderstanding the purpose of the so-called SWR meter - the very last of
the meters remaining on the front panels of our commercial black-box
transmitters.

They will soon go.

But what does it matter. It's only a hobby. I still get my pleasures from
it. And no doubt so do you.
----
Reg, G4FGQ