Hi all,

it's time to build new antennas for V/UHF season. Until now I always
used over the boom insulated elements mounting and in almost all cases
folded dipoles with 4:1 coaxial balun/transformer. In one case I
changed this driven element to a simple split dipole because the
antenna didn't seem to work well (when in facts was my homebrew tx
which wasn't working really well).
Now I read in some web pages that split dipoles work better for yagis
(no balun loss, balun is narrowband, split dipole can be easily
tuned...). This make enough sense to me (doesn't it?) so I'm willing
to use this driven element on the new antennas.
Now the question for the experts:

is this driven element really "better"? How about braid currents?

In the future yagis I want to use insulated through the boom elements
(they are really easier to manufacture for me this way). With folded
dipole the element's plane will pass approximately on the center of
the folded dipole gap, if however the driven element is a split
dipole, this element will be mounted over the boom and insulated for
mechanical and electrical reasons, thus the driven element will lay in
a different plane than all the other elements. Is this acceptable?

Thanks in advance for all hints.

best 73 de
IZ8DWF Francesco

Nya - make it a Quagi!
DE is a loop
Refl is a loop
all directors are straight elements
more fun to make
easier to tune
wrote in message
...
Hi all,

it's time to build new antennas for V/UHF season. Until now I always
used over the boom insulated elements mounting and in almost all cases
folded dipoles with 4:1 coaxial balun/transformer. In one case I
changed this driven element to a simple split dipole because the
antenna didn't seem to work well (when in facts was my homebrew tx
which wasn't working really well).
Now I read in some web pages that split dipoles work better for yagis
(no balun loss, balun is narrowband, split dipole can be easily
tuned...). This make enough sense to me (doesn't it?) so I'm willing
to use this driven element on the new antennas.
Now the question for the experts:

is this driven element really "better"? How about braid currents?

In the future yagis I want to use insulated through the boom elements
(they are really easier to manufacture for me this way). With folded
dipole the element's plane will pass approximately on the center of
the folded dipole gap, if however the driven element is a split
dipole, this element will be mounted over the boom and insulated for
mechanical and electrical reasons, thus the driven element will lay in
a different plane than all the other elements. Is this acceptable?

Thanks in advance for all hints.

best 73 de
IZ8DWF Francesco

On 13 Feb, 05:21, "Hal Rosser" wrote:
Nya - make it a Quagi!
DE is a loop
Refl is a loop
all directors are straight elements
more fun to make
easier to tune

well, I made two quagi one year, they worked well. The problem is that
you don't easily find good design procedures for quagi (neither for
quads).

wrote in message

...

Hi all,

it's time to build new antennas for V/UHF season. Until now I always
used over the boom insulated elements mounting and in almost all cases
folded dipoles with 4:1 coaxial balun/transformer. In one case I
changed this driven element to a simple split dipole because the
antenna didn't seem to work well (when in facts was my homebrew tx
which wasn't working really well).
Now I read in some web pages that split dipoles work better for yagis
(no balun loss, balun is narrowband, split dipole can be easily
tuned...). This make enough sense to me (doesn't it?) so I'm willing
to use this driven element on the new antennas.
Now the question for the experts:

is this driven element really "better"? How about braid currents?

In the future yagis I want to use insulated through the boom elements
(they are really easier to manufacture for me this way). With folded
dipole the element's plane will pass approximately on the center of
the folded dipole gap, if however the driven element is a split
dipole, this element will be mounted over the boom and insulated for
mechanical and electrical reasons, thus the driven element will lay in
a different plane than all the other elements. Is this acceptable?

Thanks in advance for all hints.

best 73 de
IZ8DWF Francesco

On Feb 13, 3:06 am, wrote:
On 13 Feb, 05:21, "Hal Rosser" wrote:

Nya - make it a Quagi!
DE is a loop
Refl is a loop
all directors are straight elements
more fun to make
easier to tune

well, I made two quagi one year, they worked well. The problem is that
you don't easily find good design procedures for quagi (neither for
quads).


try: http://web.wt.net/~w5un/w5unqu97.htm














wrote in message

...

Hi all,

it's time to build new antennas for V/UHF season. Until now I always
used over the boom insulated elements mounting and in almost all cases
folded dipoles with 4:1 coaxial balun/transformer. In one case I
changed this driven element to a simple split dipole because the
antenna didn't seem to work well (when in facts was my homebrew tx
which wasn't working really well).
Now I read in some web pages that split dipoles work better for yagis
(no balun loss, balun is narrowband, split dipole can be easily
tuned...). This make enough sense to me (doesn't it?) so I'm willing
to use this driven element on the new antennas.
Now the question for the experts:

is this driven element really "better"? How about braid currents?

In the future yagis I want to use insulated through the boom elements
(they are really easier to manufacture for me this way). With folded
dipole the element's plane will pass approximately on the center of
the folded dipole gap, if however the driven element is a split
dipole, this element will be mounted over the boom and insulated for
mechanical and electrical reasons, thus the driven element will lay in
a different plane than all the other elements. Is this acceptable?

Thanks in advance for all hints.

best 73 de
IZ8DWF Francesco

Francesco,
The 'best' driven element is one that is the easiest and most
practical for you to make/use. I'm sure that someone has done testing
of this sort, and I also think that there isn't all that much
difference in performance (all things considered). Lots of variables
in that "best" qualification!
- 'Doc

On 16 Feb, 22:07, "Jimmie D" wrote:
wrote in message




well, I made two quagi one year, they worked well. The problem is that
you don't easily find good design procedures for quagi (neither for
quads).

Thats probably because both antennas can be made to incredibly slack
tolerances and still work quite well. I hacked together a Quagi for my cell
phone a few years ago while camping that worked beter than my factory made
yagi.


hmmm that's not entirely true in my experience. One year I made a 4
elements quad for the 50 MHz band, simulated with nec using bare wires
and no boom, then built with metallic boom (and insulated wire spokes
of course) and with insulated wires, same diameter as in the
simulation. The result was so badly detuned that it actually had more
gain in the back direction than the forward one, SWR was like 3:1.
Probably the effect was due to insulated wire, but never investigated
further, I just dismantled it and built an 8 element yagi instead.
So far though nobody answered my original question as wether unaligned
driven element on yagis will have or not effects on tuning/
performance.

Thanks
Francesco IZ8DWF