Amerigo Vespucci wrote:
"Cecil Moore" wrote in message
t...
Amerigo Vespucci wrote:
The way I understood it was the best way to feed it was with ladderline
or something equal to it.
Did anyone tell you that the matching section needs to be
about 0.2 wavelength?

Explain?

To make an EDZ system resonant, i.e. a resistive impedance
looking into the feedline, the ladder-line needs to be
about 0.2 wavelengths long (plus N*1/2 wavelengths).
--
73, Cecil http://www.w5dxp.com

wrote in
ups.com:

On Jul 15, 9:41 am, "Amerigo Vespucci" wrote:
I constructed an extended double zepp for
10 meters out of #12 solid house wire .
I didn't have any ladder line laying around so I decided to make my
own but all I had was some #10 stranded wire. I made the spacers 1"
apart and and put about one per foot and the total feedling is
approximately 25 ft. and it's going through an MFJ 941E Versatuner .
I can't get my SWR's below 2 . I'm sure there are a lot of varibles
here but I was hoping someone could point me in the right
direction.My first guess is that I should have used the #12 for the
feedline and the #10 for the antenna .
Thanks in advance ,
Will

Seems kind of strange the tuner would not match it..
The spacing probably has more effect on the feedline Z
than the wire diameter. Shouldn't really be that critical.
The wider the spacing, the higher the Z..
I guess you could try a different length of line..
Or scrounge up some other ladder line, maybe with a
different length. Even 300 TV line would be ok if it's
not wet.
Myself, I used to feed them with coax, and coax
series transformers. I imagine you could also feed
with coax and use twin matching coils at the feedpoint
for both sides of the element. Same as matching a
5/8 GP, you are just doing the same with a complete
antenna. I've never tried it, but it should work.

My very first antenna project was a straight 20m zepp, end fed with
homebrew 600-ohm line 1/4 wave long just like in the books. I never ever
measured the SWR or even transmitted on it, but it was one GREAT
receiving antenna for 20m (that was in my SWL days).


--
Dave Oldridge+
ICQ 1800667

"Cecil Moore" wrote in message
et...
Amerigo Vespucci wrote:
"Cecil Moore" wrote in message
t...
Amerigo Vespucci wrote:
The way I understood it was the best way to feed it was with ladderline
or something equal to it.
Did anyone tell you that the matching section needs to be
about 0.2 wavelength?

Explain?

To make an EDZ system resonant, i.e. a resistive impedance
looking into the feedline, the ladder-line needs to be
about 0.2 wavelengths long (plus N*1/2 wavelengths).

Thanks Cecil,that may have a lot to do with it.
73 ,Will
BTW call here is Kilo Alph three Victor India Delta


--
73, Cecil http://www.w5dxp.com

On Jul 16, 7:04 am, (Rick) wrote:
On Sun, 15 Jul 2007 18:43:14 GMT, "Amerigo Vespucci" wrote:
I tried pruning the antenna a couple of inches and fiddled with the feeder
line and manged to get mr SWR's down below two but with a tuner I'm still
not happy. My rig is a Kenwood TS 530S so the finals are a little more
forgiving

Amerigo,
Are you expecting that if you get the SWR lower your finals will run cooler?
Because the reflected power into them will be less?

(Hey Walt !! We need you)

Rick K2XT

If it were solid state, I can see wanting to get below 2:1 a bit..
Gives
you more usable bandwidth. But for the hybrid kenwoods with 6146's,
it really doesn't matter. Improving his match from 2:1 will not really
make any difference at all. With those radios, as long as the load
can be matched with the "LOAD" control within it's normal setting
range, it's good nuff. I doubt a 2:1 load is off enough to hurt a pair
of those tubes as far as any extra heat. The radios have a fan.
So.. He can improve it, if he doesn't have anything else to do,
but I would not expect it to make any real difference, except
that the "LOAD" control will end up being in it's more normal
appx 1/3 to 1/2 setting rather than lower, or higher.
It will not effect his signal at all. Any difference would be
unnoticable.
MK

Another thing to consider when using the EDZ on higher bands (to get
multi-band perfomance) is that it will not do well if you have constructed
this as an inverted vee instead of a flat top. If you model the EDZ on
higher freq in an inverted vee configuration, you will see the predominance
of higher lobes (higher take-off-angle).

I ran a 20m EDZ for years and found that I had to make it a flat top for it
to perform best, even on the design band. On higher bands it was a disaster
in the inverted vee configuration. Some playing around with EZNEC showed me
why (3-D view). The gain was still there, but it was all in the wrong
direction (highly elevated).

Once I took care to go flat-top or to have very, very slight vee'ing, the
antenna worked wonderfully on 20m and decently on the bands above.

....hasan, N0AN
"Walter Maxwell" wrote in message
...
On Sun, 15 Jul 2007 15:53:48 GMT, "Amerigo Vespucci"
wrote:

snip
The way I understood it was the best way to feed it was with ladderline or
something equal to it. I looked at the wireman website and saw their 450
ohm
ladderline is only like 26 cents a foot so I'll order 80 feet of it and
send
the antenna up higher and take it from there. The reason I built the EDZ
is
it has 3 db over a dipole and it will also work for other bands with a
tuner.Another reason I made the EDZ is a real estate issue(lacking) so
something monsterous would be out of the question, but hey that's what
makes
ameteur radio such a great hobby,the experimentation that goes along with
it.

Hi Amerigo,

The transmission line you constucted should work just fine--don't go
buying any more line, because the
difference will be insignificant.

And another point you should be aware of is that the 3dB improvement using
the EDZ is only in the direction at
right angles to the antenna, because the broadside lobe of the EDZ is
somewhat narrower than that of the 1/2
wave dipole, and as a result, the gain in all other directions is LESS
than that of the 1/2 wave dipole.

Walt, W2DU