"Owen Duffy" wrote in message
...
Hello Ian,

Ian White GM3SEK wrote in
:

...
In fairness, Gordon did say: "Departures from these rules are possible
for special applications outside the scope of this discussion." The
exceptions identified above would be exactly what he had in mind.

Yes, he does make that statement. I focussed on the diagram.

I guess his "WRONG!" means "possibly wrong (see text)".


Reversed connections and/or unequal feeder lengths certainly can be
used, but they are advanced techniques requiring clear intent and
careful engineering. In all other cases they will be "WRONG" as Gordon
says.

I received comment on my antenna described at
http://www.vk1od.net/4over4/ as follows: 'It "doesn't" work because you
have inserted a half-wave time delay in the feed to one antenna (in your
case it appears to be the upper antenna) which tilts the beam up or down
a bit (in your antenna, it will tilt upwards)' and in following
discussion it is asserted that although the feed to one antenna is
transposed, it does not correct the additional half wave phase shift of
the longer branch.

Gordon's paper was offered as support for that position.

I think my design is sound, the rationale is set out in the article. I am
a little flattered if it is considered an advanced technique, but it
seems to me fairly elementary.

Actually, since posting the original article, I followed up on Gordon's
reference to the ARRL Antenna Handbook. It has a diagram that shows
pretty much what I did, it is (c) at http://www.vk1od.net/lost/Fig7.png .
(The difference in my case is that the stacking distance was chosen for
optimal pattern by trial and error with an NEC model, and the coax has a
velocity factor around 0.82.)

Owen

Hi Owen

Richard Clark once told me how to combine 4 antennas in an array. He got
me to feed 4 antennas, 50 ohms each with 50 ohm coax with no dividers. I
just fed each antenna with 50 ohm coax. At the point where the 4 coaxes
get combined, I connected two coaxes in series and the other two also in
series. Then parallel them to get back to 50 ohms. The result is two 50
ohm loads in series to make 100 ohms and with the other 100 ohms in
parallel, the combination is a good 50 ohm load. You can see a sketch in
the Feb 2008 QST. It works pretty slick when the antennas are 50 or 70
ohms where it is easy to get the right coax impedance.

Jerry KD6JDJ

"Jerry" wrote in
:

....
Hi Owen

Richard Clark once told me how to combine 4 antennas in an array.
He got
me to feed 4 antennas, 50 ohms each with 50 ohm coax with no dividers.
I just fed each antenna with 50 ohm coax. At the point where the 4
coaxes get combined, I connected two coaxes in series and the other

Can you explain in more detail what you mean by "I connected two coaxes in
series"?

two also in series. Then parallel them to get back to 50 ohms. The
result is two 50 ohm loads in series to make 100 ohms and with the
other 100 ohms in parallel, the combination is a good 50 ohm load.
You can see a sketch in the Feb 2008 QST. It works pretty slick when
the antennas are 50 or 70 ohms where it is easy to get the right coax
impedance.

Owen

"Owen Duffy" wrote in message
...
"Jerry" wrote in
:

...
Hi Owen

Richard Clark once told me how to combine 4 antennas in an array.
He got
me to feed 4 antennas, 50 ohms each with 50 ohm coax with no dividers.
I just fed each antenna with 50 ohm coax. At the point where the 4
coaxes get combined, I connected two coaxes in series and the other

Can you explain in more detail what you mean by "I connected two coaxes in
series"?

two also in series. Then parallel them to get back to 50 ohms. The
result is two 50 ohm loads in series to make 100 ohms and with the
other 100 ohms in parallel, the combination is a good 50 ohm load.
You can see a sketch in the Feb 2008 QST. It works pretty slick when
the antennas are 50 or 70 ohms where it is easy to get the right coax
impedance.

Owen

Hi Owen

I dont know how to include pictures in this text.

I would draw two touching circles to represent the outer conductors. The
generator is fed between to the inner conductors. Hence, two 50 ohm loads
on the coaxes will look like a 100 ohm load to the generator.

Jerry

"Jerry" wrote in
:


"Owen Duffy" wrote in message
...
"Jerry" wrote in
:

...
Hi Owen

Richard Clark once told me how to combine 4 antennas in an array.
He got
me to feed 4 antennas, 50 ohms each with 50 ohm coax with no
dividers.
I just fed each antenna with 50 ohm coax. At the point where the
4
coaxes get combined, I connected two coaxes in series and the other

Can you explain in more detail what you mean by "I connected two
coaxes in series"?

two also in series. Then parallel them to get back to 50 ohms.
The result is two 50 ohm loads in series to make 100 ohms and with
the other 100 ohms in parallel, the combination is a good 50 ohm
load. You can see a sketch in the Feb 2008 QST. It works pretty
slick when the antennas are 50 or 70 ohms where it is easy to get
the right coax impedance.

Owen

Hi Owen

I dont know how to include pictures in this text.

I would draw two touching circles to represent the outer conductors.
The
generator is fed between to the inner conductors. Hence, two 50 ohm
loads on the coaxes will look like a 100 ohm load to the generator.

Jerry

Ok, I understand, you the two inner conductors with a 100 ohm load
between them.

You have another pair like that from the other two arrays.

How do you connect them to the main feedline.


Owen

"Owen Duffy" wrote in message
...
"Jerry" wrote in
:


"Owen Duffy" wrote in message
...
"Jerry" wrote in
:

...
Hi Owen

Richard Clark once told me how to combine 4 antennas in an array.
He got
me to feed 4 antennas, 50 ohms each with 50 ohm coax with no
dividers.
I just fed each antenna with 50 ohm coax. At the point where the
4
coaxes get combined, I connected two coaxes in series and the other

Can you explain in more detail what you mean by "I connected two
coaxes in series"?

two also in series. Then parallel them to get back to 50 ohms.
The result is two 50 ohm loads in series to make 100 ohms and with
the other 100 ohms in parallel, the combination is a good 50 ohm
load. You can see a sketch in the Feb 2008 QST. It works pretty
slick when the antennas are 50 or 70 ohms where it is easy to get
the right coax impedance.

Owen

Hi Owen

I dont know how to include pictures in this text.

I would draw two touching circles to represent the outer conductors.
The
generator is fed between to the inner conductors. Hence, two 50 ohm
loads on the coaxes will look like a 100 ohm load to the generator.

Jerry

Ok, I understand, you the two inner conductors with a 100 ohm load
between them.

You have another pair like that from the other two arrays.

How do you connect them to the main feedline.


Owen

Hi Owen

The two 100 ohm loads in parallel give a 50 ohm load to the 50 ohm coax
main feed line. I used a ferrite "balun" where the unbalanced 50 ohm
*main feed line* connects to the center conductors that are connected to be
a 50 ohm load. .

Jerry KD6JDJ

"Jerry" wrote in
:

....
The two 100 ohm loads in parallel give a 50 ohm load to the 50 ohm
coax
main feed line. I used a ferrite "balun" where the unbalanced 50
ohm *main feed line* connects to the center conductors that are
connected to be a 50 ohm load. .

You didn't mention the balun in your fist posting. Without an effective
balun, the system would be quite poor.

In each pair of antenna side coax lines where the shields are tied together
and the inners are used for a 100 ohm connection point, you drive one coax
in opposite phase to the other. Your description did not note that there is
particular phasing requirement for the coax lines to the antennas, and
polarity of connection of the DEs.

BTW, you have constructed a type of power divider. There are a lot of
different ways to do it.

Owen

"Owen Duffy" wrote in message
...
"Jerry" wrote in
:

...
The two 100 ohm loads in parallel give a 50 ohm load to the 50 ohm
coax
main feed line. I used a ferrite "balun" where the unbalanced 50
ohm *main feed line* connects to the center conductors that are
connected to be a 50 ohm load. .

You didn't mention the balun in your fist posting. Without an effective
balun, the system would be quite poor.

In each pair of antenna side coax lines where the shields are tied
together
and the inners are used for a 100 ohm connection point, you drive one coax
in opposite phase to the other. Your description did not note that there
is
particular phasing requirement for the coax lines to the antennas, and
polarity of connection of the DEs.

BTW, you have constructed a type of power divider. There are a lot of
different ways to do it.

Owen

the simpler way is to just parallel all 4 of the 50 ohm loads which gives
you a 12 ohm load at the common point, then parallel 2 pieces of 50 ohm coax
1/4 wave long to form a 25 ohm matching section, that will get you back to a
50 ohm common point with no need for a balun.

Owen Duffy wrote:
More likely, 2 - 1/4 wave (with velocity factor)50 ohm coax's to a
"Tee" fitting-- Each end also to a "Tee" fitting . ( all 50 ohm coax)
(power devider)

2x50 -----------------

2X Quarter wave | "T" fitting source 50 Ohm

2x50 -----------------

IF this is clear enough-- Jim NN7K

Jerry

Ok, I understand, you the two inner conductors with a 100 ohm load
between them.

You have another pair like that from the other two arrays.

How do you connect them to the main feedline.


Owen

Jim-NN7K . wrote in news:9ch1l.9958$yr3.334
@nlpi068.nbdc.sbc.com:

Owen Duffy wrote:

Firstly, I didn't write the following, Jim did.

More likely, 2 - 1/4 wave (with velocity factor)50 ohm coax's to a
"Tee" fitting-- Each end also to a "Tee" fitting . ( all 50 ohm coax)
(power devider)

2x50 -----------------

2X Quarter wave | "T" fitting source 50 Ohm

2x50 -----------------

IF this is clear enough-- Jim NN7K


Jim, are you introducing another scheme, or were you trying to explain
Jerry's scheme. We sorted Jerry's scheme, he just overlooked some vital
details in his first description. (I haven't said it to date, but I
dislike Jerry's scheme, principally over its use of the balun.)

Yours is another scheme.

There are a lot of ways to do it.

The original question was over an article's diagram that stated that
unequal lines are "WRONG!".

Yours and Jerry's responses have not dealt with the original posting, but
if anything offered alternatives that might be seen to suggest the
original configuration is flawed.

Owen

Keeping in mind simplicity, and , using equal length of 50 0hm
to this power splitter- all antennas should be in phase (all
Left elements , to properly phase), and that it gives 4-50 ohm loads
for one 50 ohm source. Why reinvent the wheel?? Jim NN7K


Owen Duffy wrote:
Jim-NN7K . wrote in news:9ch1l.9958$yr3.334
@nlpi068.nbdc.sbc.com:

Owen Duffy wrote:

Firstly, I didn't write the following, Jim did.

More likely, 2 - 1/4 wave (with velocity factor)50 ohm coax's to a
"Tee" fitting-- Each end also to a "Tee" fitting . ( all 50 ohm coax)
(power devider)

2x50 -----------------

2X Quarter wave | "T" fitting source 50 Ohm

2x50 -----------------

IF this is clear enough-- Jim NN7K


Jim, are you introducing another scheme, or were you trying to explain
Jerry's scheme. We sorted Jerry's scheme, he just overlooked some vital
details in his first description. (I haven't said it to date, but I
dislike Jerry's scheme, principally over its use of the balun.)

Yours is another scheme.

There are a lot of ways to do it.

The original question was over an article's diagram that stated that
unequal lines are "WRONG!".

Yours and Jerry's responses have not dealt with the original posting, but
if anything offered alternatives that might be seen to suggest the
original configuration is flawed.

Owen