Ron Walters wrote:
Would appreciate comments relative to the Optibeam Log Periodic 14-30MHz
antennas, I am also considering the SteppIR antenna but I am concerned
with the mechanical and electric potential problems with that antenna.
Getting on in age and tower climbing is s chore for me. Any suggestions
or comments?

Ron W4LDE
The Only problem with the Optibeam is that their gain figures are
honest! I think if you look at Cebiks web page a at his Log periodic
models you also see how good LPDA's can be.

What makes both the LPDA and the Optibeam look bad is the exagerated
gain claims from old antennas designs. We see LPDA's get tarred with
this brush daily, yet we know any decent lpda will just about perform
as well as any mutiband tribander.

Whats amusing is that you see people time and time say that a 5 element
monoband will beat a 32 foot lpda by several S units. Yet we know that
a decent LPDA of this boom length will have a gain of about 8dbi versus
a monoband antennas gain of 10dbi! So you tell me where even 1 s units
gain comes from?

What does not help the logs case is the dishonest manufacturers who blow
up their gain figures. People like Tennadyne, who seem to mix up dbi
with DBd.

If it was my money and i wanted a small multiband beam antenna i would
buy the Optibeam, because 2 or 3 dbi does not mount to much on HF. I
would rather go for all band coverage with reliability versus something
like a Steppir which still is unproven.

Optibeam have a nice model that covers from 40 through to 10 even 30
meters. Now if you looked at the same size log needed to achieve that
with similar gain you see what a good design it is for ham radio. I
dont buy all the crap spun by Optibeams owner about LPDA;s and harmonics
etc. Harmonic suppression is a transmitter problem should never be the
antennas problem. If you have a receiver that cant handle a log because
of 2nd order IMD issues you have a crap receiver.

Whats also interesting is that if you model a stack of LPDAs like N08D
has which is six logs on a 200 ft tower you see the gain is just about
equivalent to a monoband stack, and this is from 13 to 30 mhz. There is
some guy in W1 land who runs 2 big logs on a 100ft tower, if you heard
his signal from a distance you would be impressed.

But dont worry too much about gain in any decent multiband beams like
the steppir and the optibeam. I beat stations with a 4 element steppir's
antennas with a high double extended zepp antenna. I would rather have
a low gain LPDA up at a 100 ft than a Steppir down on a 30ft pole. In
fact a lazy H at a decent height would perform just as well as most
small tribanders or a small 2 element cubical quad.

You dont have to take mine or anyones word for it, just look at the
reliable models on Cebiks web page. You soon see that most of the gain
claims by optibeam. Force 12 is another company that has decent honest
figures.

Zenki