"Jerry Martes" wrote in message
news:XJqSd.17298$uc.14470@trnddc01...



" wrote in
message news5bSd.33636$tl3.9146@attbi_s02...
Regarding antenners, thats right,antennas.
Plenty of listings for various gains achieved with antennas
but I have not seen any similar listings for F/R and F/B.
Is there any around so I can see what can be or has been attained or
is blocking of rear signals of little consequence for todays hams. I can
see that being true
for when the band has just opened and propagation has not opened to the
rear or
with net operations so perhaps gain is every thing after all.
It is my opinion that if interest/efforts are increased first in
deflecting the rear action to the
front first and thereby INCREASING the front lobe width there will be
more opportunities
for increasing gains without the side lobes and narrow forward lobes that
accompany Yagi's.
as well as shorter booms. ( more deflectors/reflectors perhaps)
( no religeous, porno or genocide preaching please, fighting to see which
is best
could take place on boat anchor nets to see which has taken position of
the lowest level)
Regards
Art


Art

Excuse me if I misunderstand your post above. It reads to me that you
have an interest in building an antenna that minimizes "side lobes" to the
rear of the main beam.

Correct..minimise or remove
..
In my experience with directional antennas I have not been able to
corelate minimum side lobes with maximum gain.

Oh I fully agree with that observation and that is another part of my
thinking
as it should never be so UNLESS you are captive to Yagi thinking.

I'd suggest that the sidelobes will probably never be held lower than the
same level as the forward gain. That is a 20 db gain antenna will have
side lobes no lower than - 20 db with respect to the main lobe.


20 db gain would not be rotatable at HF which represents a huge drawback,
better to stay with a rombic thinking and cancel the energy complely to the
rear of the
feed point.

Again that is true if you are captive to the Yagi
Make no mistake the Yagi is as about as simple a thing to make that works
well,
it is doubtfull with respect to simplicity it can be beat.

Or, another
way to put it is; there will always be a side lobe that gets up to or
above isotropic level somewhere in the pattern.

Then think what actualy generates a lobe whether directional(frontal)
or at the rear.



I think I'm misreading your post because I read it to say that main lobe
could be increased in width while increasing the antenna sensitivity.
That doesnt make sense, so I guess I'm not understanding.

Yes you misunderstood. Bank to the ballon if all the volume to the rear
of the figure 8 ahat the new diameternd placed in the front of the feed
point it is obvious will be wider and with more gain and if I might adde NO
sidelob.
You have to return to basics to understand that it is energy to the rear
that
generates side lobes at the rear.


And, I submit that, with yagis, there is so little energy radiated in the
sidelobes of a 15 db gain Yagi antenna that *all* the sidelobe radiation
redirrected to be included in the main lobe wont add significantly to the
Practical Useability of the antenna. I write Practical Useability
because I want to distinguish that from scientific exploration of antenna
gain, which accounts for fractions of one db.

Well that is the essence of my disagreement with the masses which I admit
I have not yet released my findings. Think about it, I could have a single
directive lobe
that has twice the energy of a standard dipole in unidirectional form
and with a broader lobe.and I have yet to discuss yagi type manipulations
that
narrow the lobe ,which can be unhelpful, and start from a new datum line if
one
wants to determine gain per unit length type thinking that goes with
Yagi,s.
..Maybe some experts can add some view points, after all it is a general
discussion group on antennas where many believe all is already known
and in a book....... grin
Regards
Art ........KB9MZ

Jerry