RadioBanter - View Single Post - SUPER J-POLE BEATS YAGI BY 1 dB

February 7th 05, 09:43 PM

wrote:

What lack of decoupling? It's got the
coax inductive choke on the input, 4 turns
of 4" diameter.

I don't recall seeing that in the picture. But even still, I
wonder if it's as good as a full 1/4 wave decoupling cone, or
radials...Much better than nothing though...

Take another look...

Yea, but if you are going to post a CAPS thread
claiming a j pole beats a yagi by 1 db, most are
going to assume the yagi isn't crippled up...
It's sort of Frackish.....:/

How broad or narrow is the front lobe
of your yagi? How many degrees? Much
smaller than 180 no doubt.

No doubt...

I'm not trying to rain on your parade, and surely
applaud you for building these, I just don't quite
get the purpose of such a comparison...Everyone
already knows what the gains of the antennas are..
Well, except for the de-tuned yagi... I mean,
is it really a surprise a collinear might beat
a yagi with about half the normal gain of the
NBS 3 el?
I'll bow out...I really have no problem with the
antenna, etc...I just wanted to stir it, being you
have this frackish thread title... MK

Oh, ok, so you thought i was making some
sort of grand statement that a Super J will
beat a Yagi regardless of the design. That's
not what i'm saying at all.

With THIS PARTICULAR 180 degree yagi,
the Super J beats it in all directions.
Really i should have just made the thread
title, "Observations on the Super J-pole
and Wide angle Yagis in the VHF broadcast
band".

If someone can come up with a 3 element
yagi (we wanted to keep the size down), with
a 180 degree front lobe, and about 11 dB F/B
ratio, that has a better than 4.5 dBi in the
front lobe, i'd like to see it. Use EZNEC
or whatever simulator you have, and make
an H-plane plot... i'd like to see that.

The reason we wanted 11dB F/B ratio,
is that for this particular usage, it
was NOT on the edge of town, and so we
still wanted to have enough ERP to the
back side.

Slick