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

I looked at their web site and did not see a 'Log Periodic'.

Their antennas seem to be Yagi based. A L-P is a driven array, not parasitic,
and broad banded so that the VSWR never exceeds a max value, typically 1.7:1,
ANYWHERE in the spectrum from 14 to 30 MHz in the bandwidth you mentioned.

Do you have a model number?

/s/ DD W1MCE

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

Dave wrote:

I looked at their web site and did not see a 'Log Periodic'.

Their antennas seem to be Yagi based. A L-P is a driven array, not
parasitic, and broad banded so that the VSWR never exceeds a max value,
typically 1.7:1, ANYWHERE in the spectrum from 14 to 30 MHz in the
bandwidth you mentioned.

Do you have a model number?

/s/ DD W1MCE


Additional info Log Periodics.

Typical VSWR values for a 13 to 30 MHz LP are as follows:

13.5 MHz ... 1.7:1
13.7 MHz ... 1.6:1
13.9 MHz ... 1.4:1
14.1 MHz ... 1.3:1
14.3 MHz ... 1.4:1
14.5 MHz ... 1.5:1
14.7 MHz ... 1.7:1
14.9 MHz ... 1.7:1
15.1 MHz ... 1.6:1
15.3 MHz ... 1.5:1
15.5 MHz ... 1.4:1
15.7 MHz ... 1.3:1
15.9 MHz ... 1.3:1
16.1 MHz ... 1.4:1 ... continuing through 30 MHz for a 13 to 30 MHz antenna.

Note: On 10 meters my VSWR does not exceed 1.4:1 anywhere from 28.0 to 29.7 MHz.
I don't believe a Yagi design is that broadbanded.

The VSWR on my LP does not exceed 1.7:1 anyplace between 13.5 and 31 MHz. It
varies slightly between 1.7:1 and 1.3:1 minimum.

Gain is effectively constant between 13 and 30 MHz. However, it is slightly
lower than a well designed 3 element Yagi. [~-0.5 dB]
Efficiency, however, is slightly better than a trapped Yagi [no trap losses].
Physical size is larger than a trapped Yagi.
F/B ratio on 14 MHz is lower than a Yagi but will match a yagi on 18 through 30 MHz.

I chose a LP because I wanted full coverage of the HF spectrum from 13 to 30
MHz. [Including USAF MARS & 17 and 12 meters] A 5 band Yagi only covers 5
segments of that spectrum.

If I were interested in one or two bands only, I would go to a full sized 4 or 5
element Yagi for for each band and get excellent gain, efficiency and F/B.
[Assuming I had the $$$$]

Dave wrote:
I looked at their web site and did not see a 'Log Periodic'.

Their antennas seem to be Yagi based. A L-P is a driven array, not
parasitic, and broad banded so that the VSWR never exceeds a max value,
typically 1.7:1, ANYWHERE in the spectrum from 14 to 30 MHz in the
bandwidth you mentioned.

Do you have a model number?

/s/ DD W1MCE

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


Dave,

Thanks for your comments, the Optibeam antenna model I was looking at is
the OB9-5 broadband antenna. The spec's seem good, low wind load and
looks like it would survive in the sunny south were we do get those darn
Hurricanes. I live in Central Floria. My TA-33 has gone through 4
storms with some very gusts of over 100 MPH and still preforms without
a change from the day I put it up back in 1988, almost 18 years, thats
service.

The other antennas I am looking at is the Summer XP504-6 LP that is
rated 13-54 MHz and the Cushcraft ASL2010. The gain figures look higher
than the Optibeam but I guess that its all relative.

Theres no doubt that the SteppIR 3- element is a great beam, but from
what I have read over the past few years since it first hit the market
is that there has been problems, both mechanical and electrical. That
fact frightens me, here I live in the lighting capital of the world and
also from time to time need to adjust to Hurricanes, if I didn't love
golf also I probably live future up north in SC or NC but thats not the
issue. In a few years my days climbing towers will get very difficult
and probable not to smart.

After looking at the choices one has in a multi-band antenna for 20-6
meters I have come to realize that the LP maybe my alternative for a
long term survivable antenna. You were right after looking at the
Optibeam it is not a LP like the Summer or Cushcraft.

What bothers me about the current LP offering is I do not see many
opinions or comments relative to this type of antenna, guess everyone
likes the new SteppIR and before its over I may re-think my choices.

Again thanks for the comment

73 - Ron W4LDE

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

Zen wrote:
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

Zen,

Thank you for the comment and time it took to type it, very informative.

Ron W4LDE

Dear Ron:

Go for a good, well made, USA LPDA. As an example: the Tennadyne T10
(www.tennadyne.com) compared to the OB9-5 has a longer boom, uses more
material, has a lower cost, has no custom/duty issues, and a long track
record.

The gain figures posted by Tennadyne are reasonable and well labeled.
For MARS like service, an LPDA can not be matched.

If you decide on a LPDA, contact me off-line and I can provide some
simple ideas on simplifying installation.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:

"Ron Walters" wrote in message
...
Dave wrote:
I looked at their web site and did not see a 'Log Periodic'.

Their antennas seem to be Yagi based. A L-P is a driven array, not
parasitic, and broad banded so that the VSWR never exceeds a max value,
typically 1.7:1, ANYWHERE in the spectrum from 14 to 30 MHz in the
bandwidth you mentioned.

Do you have a model number?

/s/ DD W1MCE

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


Dave,

Thanks for your comments, the Optibeam antenna model I was looking at is
the OB9-5 broadband antenna. The spec's seem good, low wind load and
looks like it would survive in the sunny south were we do get those darn
Hurricanes. I live in Central Floria. My TA-33 has gone through 4
storms with some very gusts of over 100 MPH and still preforms without
a change from the day I put it up back in 1988, almost 18 years, thats
service.

The other antennas I am looking at is the Summer XP504-6 LP that is
rated 13-54 MHz and the Cushcraft ASL2010. The gain figures look higher
than the Optibeam but I guess that its all relative.

Theres no doubt that the SteppIR 3- element is a great beam, but from
what I have read over the past few years since it first hit the market
is that there has been problems, both mechanical and electrical. That
fact frightens me, here I live in the lighting capital of the world and
also from time to time need to adjust to Hurricanes, if I didn't love
golf also I probably live future up north in SC or NC but thats not the
issue. In a few years my days climbing towers will get very difficult
and probable not to smart.

After looking at the choices one has in a multi-band antenna for 20-6
meters I have come to realize that the LP maybe my alternative for a
long term survivable antenna. You were right after looking at the
Optibeam it is not a LP like the Summer or Cushcraft.

What bothers me about the current LP offering is I do not see many
opinions or comments relative to this type of antenna, guess everyone
likes the new SteppIR and before its over I may re-think my choices.

Again thanks for the comment

73 - Ron W4LDE