"merlin-7" wrote in
:

I know that an inverted V is for the most part omni directional, but
what
about an inverted v that is only somewhat inverted? Would that not
give you a pattern more shaped like an egg?



The directivity of a half wave dipole over real ground varies with
height, and elevation angle. At the zenith it is omni directional, and at
lower elevations it has some directivity, but nothing like a dipole in
free space. Inclining the legs as in an inverted V dilutes the nulls
further and so reduces directivity, less so for large included angle.

So, the combination of an inverted V and mounting low to real ground
reduces directivity.

If you raise your dipole centre height, and decrease the included angle,
I expect that one will offset the other's effect on the pattern to some
extent.

Owen

A question for you experts out there...
I currently use a fan dipole (kind of a fan anyway)

It has 3 elements off of each side from the feed point.
A 66 foot or 132 feet total length
A 33 foot or 66 feet total length
and a 16 foot or 32 feet total length.(this is before it was tuned so
measurements are not exact)

The wires are spread 1 foot apart from each other, 18 inches from the feed
point. (where the wires are connected to the feed point, they V out from
there, to a point 18 inches from the feed point where the 1st spreader is
located, placing each wire 1 foot apart)

The wires are (hung) under each other from that point, 1 foot apart over
the total length of each wire with the longest wire (the 66/132) on top (the
33/66) in the middle and (16/32) on the bottom.

I used the longest wire to support the (pvc) spreaders for the wires
hanging under it.

The feed point is at about 40 feet with the ends of the (66/132) at about
22 feet (the ends of the shorter wires are higher, due to the fact they end
higher up the inverted V.

It has an air wound choke at the feed point fed with 50 ohm coax.

I have several questions regarding this set up.

What are the pros and cons of fan dipoles like this? I have never heard of
a fan dipole with each element being hung under each other so I have no data
to compare it to.

I would like to keep this set up when I move to my new QTH in a few months
but raise it to 60 feet or so.
I know that an inverted V is for the most part omni directional, but what
about an inverted v that is only somewhat inverted? Would that not give you
a pattern more shaped like an egg?

I really do not wish to put up a wire for each band as the one I have now
can run everything from 10m to 80m and even the low side of 160, right
around 1.8 mhz (I havent figured that one out yet)with a tuner.

What are the pros and cons of adding more wires? (other than tuneing the
wires being more of a pain)

I get very little interaction between the wires (maybe due to the fact they
are spread apart so close to the feed point) or I just got lucky, hi hi

I am looking for ideas or someone that is great with an antenna program,
that can tell me what my antenna is doing now and how to improve it at
around 60 feet at the feed point.

It looks like my shack will be up befor my new home will be ready (solar
power has its advantages) So I need to plan the antenna and the mounting
points for the ends of the wires.(angle or slope) in other words, how high
the ends need to be.

I plan on placeing the wires east / west broadside but would like a bit of
an omni pattern to reach the east coast(NY to FL) from jacksonville NC.

Sorry for the long post but I know of a few out there that can give me some
ideas that I have overlooked. It is better to plan ahead .....

Thanks
Joe
KI4ILB

On Mon, 19 Mar 2007 20:28:44 -0500, "merlin-7"
wrote:

A question for you experts out there...
I currently use a fan dipole (kind of a fan anyway)
SNIP

What are the pros and cons of fan dipoles like this? I have never heard of
a fan dipole with each element being hung under each other so I have no data
to compare it to.

I haven't used the inverted-V formation, but I have used the
multi-band parallel dipole since I was first licensed in 1978. The
pros are that if the elements are 8" or closer (I never ran them
further apart), I get a broader bandwidth per band. (That comes in
handy on 80 & 40 meters. ) you don't need a tuner for the three bands
of your choice (adding more wires means additional bands). If you are
a cw buff, the 40 meter dipole also doubles as 15 meters.

The cons are that the antenna isn't very stealth (if that is an
issue.), if you are running an amplifier, you could be radiating the
harmonics more efficiently. It could get tangled in the wind or limbs
of a tree (I had to deal with that and place spacers closer together.)

I have never noticed a difference in the Multi-Band Parallel Dipole
MBPD (just what I call it, probably not an official name) and a mono
band dipole as far as signal strength goes. I can't model one in my
program as it thinks that is one big fat wire.



I would like to keep this set up when I move to my new QTH in a few months
but raise it to 60 feet or so.

The higher the better...



I really do not wish to put up a wire for each band as the one I have now
can run everything from 10m to 80m and even the low side of 160, right
around 1.8 mhz (I havent figured that one out yet)with a tuner.

80 should be a close double for 10 and 60 meters, 40 doubles with 15
meters and some combination of left and right wires double for the
other ward bands (I suppose - wag) unless 80 tunes for it. I don't
know about 160 as I have never tried to tune one to it.


What are the pros and cons of adding more wires? (other than tuneing the
wires being more of a pain)

Pros: instant switch to more bands without having to use tuner,

Cons: more harmonic risk, more wind load, more visible wire, more
weight, more expense.



I get very little interaction between the wires (maybe due to the fact they
are spread apart so close to the feed point) or I just got lucky, hi hi

I am looking for ideas or someone that is great with an antenna program,
that can tell me what my antenna is doing now and how to improve it at
around 60 feet at the feed point.

It looks like my shack will be up befor my new home will be ready (solar
power has its advantages) So I need to plan the antenna and the mounting
points for the ends of the wires.(angle or slope) in other words, how high
the ends need to be.

I plan on placeing the wires east / west broadside but would like a bit of
an omni pattern to reach the east coast(NY to FL) from jacksonville NC.

Sorry for the long post but I know of a few out there that can give me some
ideas that I have overlooked. It is better to plan ahead .....

Thanks
Joe
KI4ILB


I don't know what the radiation pattern will look like, but I suspect
it will be pretty much round. I would think, for the effort, it might
be well to put up two antennas, each with either three or four bands.
I mostly used 4 bands, each additional wire gets considerably more
difficult to deal with. I usually design them and space the wires
with PVC pipe which means I have to cut the pipe and add all the wires
at once or create a whole new antenna at the end.

Personally, I use #14 THHN wire which is coated and can be purchased
in various colors. I could choose different colors for each band if I
like. However, the noise factor during winter weather (ice, etc.) if
I keep them all insulated. I found that if I spaced the wires 8
inches apart, I get to reverse engineer the formula for adding bands.
This means I trim out the ten and 15 meter bands (I didn't use this
for ward bands) and then reverse engineer the formula...

x/F=L

x=468, F=Frequency in MHz, L=length in Feet.

L*F=x

Next, calculate with the new x for the additional band you desire to
add. This will narrow your trimming down to a minimum.


Good luck, I am looking forward to reading all the replies.

Buck
N4PGW
www.lumpuckeroo.com

73


--
73 for now
Buck, N4PGW
www.lumpuckeroo.com
N4PGW

On Mon, 19 Mar 2007 20:28:44 -0500, "merlin-7" wrote:

A question for you experts out there...
I currently use a fan dipole (kind of a fan anyway)

It has 3 elements off of each side from the feed point.
A 66 foot or 132 feet total length
A 33 foot or 66 feet total length
and a 16 foot or 32 feet total length.(this is before it was tuned so
measurements are not exact)

The wires are spread 1 foot apart from each other, 18 inches from the feed
point. (where the wires are connected to the feed point, they V out from
there, to a point 18 inches from the feed point where the 1st spreader is
located, placing each wire 1 foot apart)

The wires are (hung) under each other from that point, 1 foot apart over
the total length of each wire with the longest wire (the 66/132) on top (the
33/66) in the middle and (16/32) on the bottom.

I used the longest wire to support the (pvc) spreaders for the wires
hanging under it.

The feed point is at about 40 feet with the ends of the (66/132) at about
22 feet (the ends of the shorter wires are higher, due to the fact they end
higher up the inverted V.

It has an air wound choke at the feed point fed with 50 ohm coax.

I have several questions regarding this set up.

What are the pros and cons of fan dipoles like this? I have never heard of
a fan dipole with each element being hung under each other so I have no data
to compare it to.

I would like to keep this set up when I move to my new QTH in a few months
but raise it to 60 feet or so.
I know that an inverted V is for the most part omni directional, but what
about an inverted v that is only somewhat inverted? Would that not give you
a pattern more shaped like an egg?

I really do not wish to put up a wire for each band as the one I have now
can run everything from 10m to 80m and even the low side of 160, right
around 1.8 mhz (I havent figured that one out yet)with a tuner.

What are the pros and cons of adding more wires? (other than tuneing the
wires being more of a pain)

I get very little interaction between the wires (maybe due to the fact they
are spread apart so close to the feed point) or I just got lucky, hi hi

I am looking for ideas or someone that is great with an antenna program,
that can tell me what my antenna is doing now and how to improve it at
around 60 feet at the feed point.

It looks like my shack will be up befor my new home will be ready (solar
power has its advantages) So I need to plan the antenna and the mounting
points for the ends of the wires.(angle or slope) in other words, how high
the ends need to be.

I plan on placeing the wires east / west broadside but would like a bit of
an omni pattern to reach the east coast(NY to FL) from jacksonville NC.

Sorry for the long post but I know of a few out there that can give me some
ideas that I have overlooked. It is better to plan ahead .....

Thanks
Joe
KI4ILB

Joe, you are going in the correct direction with multiple dipoles fed at the same feed point. I have used that
method successfully for many years.

I discuss this method in detail in Chapter 20 of my book Reflections--Transmission Lines and Antennas, ed 1
published by the ARRL and ed 2 published by Worldradio. Ed 3 is in publication. You can download several
Chapters, including Chapter 20, from Reflections 2 from my web page at www.w2du.com.

However, if your email address is as shown on your post, I'll email you a copy of Chapter 20.

You'll find the info concerning multiple dipoles in Sec 20.2.2, Stagger-Tuned Dipoles.

Walt, W2DU

A question for you experts out there...
I currently use a fan dipole (kind of a fan anyway)

It has 3 elements off of each side from the feed point.
A 66 foot or 132 feet total length
A 33 foot or 66 feet total length
and a 16 foot or 32 feet total length.(this is before it was tuned so
measurements are not exact)

The wires are spread 1 foot apart from each other, 18 inches from the
feed
point. (where the wires are connected to the feed point, they V out from
there, to a point 18 inches from the feed point where the 1st spreader is
located, placing each wire 1 foot apart)

The wires are (hung) under each other from that point, 1 foot apart over
the total length of each wire with the longest wire (the 66/132) on top
(the
33/66) in the middle and (16/32) on the bottom.

I used the longest wire to support the (pvc) spreaders for the wires
hanging under it.

The feed point is at about 40 feet with the ends of the (66/132) at
about
22 feet (the ends of the shorter wires are higher, due to the fact they
end
higher up the inverted V.

It has an air wound choke at the feed point fed with 50 ohm coax.

I have several questions regarding this set up.

What are the pros and cons of fan dipoles like this? I have never heard
of
a fan dipole with each element being hung under each other so I have no
data
to compare it to.

I would like to keep this set up when I move to my new QTH in a few
months
but raise it to 60 feet or so.
I know that an inverted V is for the most part omni directional, but
what
about an inverted v that is only somewhat inverted? Would that not give
you
a pattern more shaped like an egg?

I really do not wish to put up a wire for each band as the one I have
now
can run everything from 10m to 80m and even the low side of 160, right
around 1.8 mhz (I havent figured that one out yet)with a tuner.

What are the pros and cons of adding more wires? (other than tuneing the
wires being more of a pain)

I get very little interaction between the wires (maybe due to the fact
they
are spread apart so close to the feed point) or I just got lucky, hi hi

I am looking for ideas or someone that is great with an antenna program,
that can tell me what my antenna is doing now and how to improve it at
around 60 feet at the feed point.

It looks like my shack will be up befor my new home will be ready (solar
power has its advantages) So I need to plan the antenna and the mounting
points for the ends of the wires.(angle or slope) in other words, how
high
the ends need to be.

I plan on placeing the wires east / west broadside but would like a bit
of
an omni pattern to reach the east coast(NY to FL) from jacksonville NC.

Sorry for the long post but I know of a few out there that can give me
some
ideas that I have overlooked. It is better to plan ahead .....

Thanks
Joe
KI4ILB

Joe, you are going in the correct direction with multiple dipoles fed at
the same feed point. I have used that
method successfully for many years.

I discuss this method in detail in Chapter 20 of my book
Reflections--Transmission Lines and Antennas, ed 1
published by the ARRL and ed 2 published by Worldradio. Ed 3 is in
publication. You can download several
Chapters, including Chapter 20, from Reflections 2 from my web page at
www.w2du.com.

However, if your email address is as shown on your post, I'll email you a
copy of Chapter 20.

You'll find the info concerning multiple dipoles in Sec 20.2.2,
Stagger-Tuned Dipoles.

Walt, W2DU




Thanks thats just what I needed. It takes a bit of the guess work out of
it.hi hi
I have not looked at the file in detail but from what I saw it looks great.
I did not see the distance in spaceing the elements apart in there and what
effect that has (I may have overlooked it)

I like fan dipoles and have no problem hanging a 5 wire one ( this time I
will measure every wire after there all tuned) just in case I need to
replace it. Tree limb, ice. etc.
I forget the name of the copper clad steel I have for the new shack, but
its the large gauge and hard to work with but should work well and stay up a
long time after I finnish cussing.

Like I said, I hang the longest wire on top and the shortest on the bottom
(under each other)

I may need to use copper strand for the shorter wires to keep from ending
up with a giant slinky.

I also use (weed eater line) from the bottom of some of the spreaders to a
point below where the ends of the dipole are tied off to keep the whole
thing from twisting up in bad weather. The short one just has a weight under
it.

Sound good?

Now, I just need to figure out the spaceing between elements. At 12 inches
I get very little interaction but someone posted, If they were closer, The
bandwith would be wider.
I am trying to preplan as much of this as I can. I do not mind climbing a
tower but the less trips I have to make the better (damn I wish I did this
when I was 20) hi hi

I currently use a fan dipole (kind of a fan anyway)
SNIP
What are the pros and cons of fan dipoles like this?....

We used one of these at a local mall for "Kids' Day" last January.
Formula-cut for 20/15/10 and errected about 25 feet high (best we
could do at the mall), with NO special "fanning" at the center, but
the ends were about 2 feet apart, and the VSWR was about 6:1 on all
bands (fortunately, we had taken a tuner).

If your VSWR is low, maybe we should have done a bunch of pruning
and cutting, but we didn't think far enough ahead!

--
--Myron A. Calhoun; W0PBV; 2001 Dunbar Road; Manhattan, KS 66502-3907
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
NRA Life Member & Certified Instructor for Rifle, Pistol, & Home Firearm Safety
Also Certified Instructor for the Kansas Concealed-Carry Handgun (CCH) license