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Little_skip February 4th 09 08:27 AM

HLP Antennas
 
Hi everyone,

I would like some help with the HLP (Hybrid Log-Periodic) Antennas if possible. I know nothing about antennas, yet I have a paper to write about HLP Antennas (characteristics, calibration and so on) and I didn't find anything about them. I found only datasheets for some of the HLP antennas (mostly from TDK). Would it be a start to search about log-periodic antennas and adapt the information? What would be the difference between them?

Maybe it would sound like a stupid question to all of you, but I really don't know where to start. Can someone give me a bit of help?

Thank you.

Jerry[_5_] February 4th 09 04:32 PM

HLP Antennas
 

"Little_skip" wrote in message
...

Hi everyone,

I would like some help with the HLP (Hybrid Log-Periodic) Antennas if
possible. I know nothing about antennas, yet I have a paper to write
about HLP Antennas (characteristics, calibration and so on) and I
didn't find anything about them. I found only datasheets for some of
the HLP antennas (mostly from TDK). Would it be a start to search about
log-periodic antennas and adapt the information? What would be the
difference between them?

Maybe it would sound like a stupid question to all of you, but I really
don't know where to start. Can someone give me a bit of help?

Thank you.




--
Little_skip


Hi Little

You are really in luck. You say you have to write about an antenna but
dont know anything about antennas. That implies that you now get to learn
about antennas unless you are content with writing about things you "dont
hnow anything about".
Get the guy who is having you write to buy you a copy of EZNEC. You can
model whatever antenna you want to get data on.

Jerry KD6JDJ



JB[_3_] February 4th 09 05:19 PM

HLP Antennas
 

"Little_skip" wrote in message
...

Hi everyone,

I would like some help with the HLP (Hybrid Log-Periodic) Antennas if
possible. I know nothing about antennas, yet I have a paper to write
about HLP Antennas (characteristics, calibration and so on) and I
didn't find anything about them. I found only datasheets for some of
the HLP antennas (mostly from TDK). Would it be a start to search about
log-periodic antennas and adapt the information? What would be the
difference between them?

Maybe it would sound like a stupid question to all of you, but I really
don't know where to start. Can someone give me a bit of help?

Thank you.
Little_skip


Hybrid Log-Periodic refers to a Log-Periodic Dipole Array antenna that uses
other types of elements in order to improve on some characteristic. One
example would be the typical TV antennas that have a UHF Yagi with Corner
Reflector using the same feed as the Log-Periodic elements. That example is
a hybrid of all three classic antenna configurations. If you were speaking
of the TDK models, you might have to look at one up-close to figure out what
technologies were involved (I have not) but it appears that it consists of a
classic Log-Periodic for VHF/UHF frequencies with additional elements for
the lower frequencies, such as linear loaded dipole or Quad elements. The
feed system is the key to hybrid multi-band and broadband antennas so that
the element configuration for one frequency is not compromised by the
inactive elements. With the TV antenna example, the LPDA and UHF Yagi are
essentially invisible to each other although they use the same feed and
boom.

Although this idea is attractive for frequency agile radios or for saving
the cost of feedline, performance is usually better for antennas optimized
for a limited range of frequencies.

It would be helpful for you to have knowledge of a variety of antenna
configurations, feed systems and technologies in order to do it justice.

You can write on anything at all. You just have to determine what you want
to convey.

I'm sure others will come out of the woodwork pretty soon.


Little_skip February 4th 09 09:23 PM

Quote:

Originally Posted by Jerry[_5_] (Post 665327)
Hi Little

You are really in luck. You say you have to write about an antenna but
dont know anything about antennas. That implies that you now get to learn
about antennas unless you are content with writing about things you "dont
hnow anything about".
Get the guy who is having you write to buy you a copy of EZNEC. You can
model whatever antenna you want to get data on.

Jerry KD6JDJ

First, thank you for reading it and trying to help. I appreciate that.
Well, the fact is that I would like to read something about them first before doing any simulation. Having no background at all, I think I wouldn't be able to use EZNEC as I should. At least a description of these equipment, how does it work, what it is used for and so on. I tried looking on some documentation, but I found some only on log-periodic antennas and the theme is actually hybrid log-periodic.

Tom Donaly February 5th 09 01:32 AM

HLP Antennas
 
Little_skip wrote:
'Jerry[_5_ Wrote:
;665327'] Hi Little

You are really in luck. You say you have to write about an antenna
but
dont know anything about antennas. That implies that you now get to
learn
about antennas unless you are content with writing about things you
"dont
hnow anything about".
Get the guy who is having you write to buy you a copy of EZNEC. You
can
model whatever antenna you want to get data on.

Jerry KD6JDJ


First, thank you for reading it and trying to help. I appreciate that.
Well, the fact is that I would like to read something about them first
before doing any simulation. Having no background at all, I think I
wouldn't be able to use EZNEC as I should. At least a description of
these equipment, how does it work, what it is used for and so on. I
tried looking on some documentation, but I found some only on
log-periodic antennas and the theme is actually hybrid log-periodic.





Try googling "EMC antenna". If the antenna you are looking for is a
hybrid of a bow-tie (degenerate biconical) antenna, and a log periodic,
you'll first have to read up on the constituent antennas and then puzzle
out how they work together. Hopefully, you haven't picked a subject that
will get you in over your head.
73,
Tom Donaly, KA6RUH

Wimpie[_2_] February 6th 09 11:52 AM

HLP Antennas
 
On 4 feb, 09:27, Little_skip
wrote:
Hi everyone,

I would like some help with the HLP (Hybrid Log-Periodic) Antennas if
possible. I know nothing about antennas, yet I have a paper to write
about HLP Antennas (characteristics, calibration and so on) and I
didn't find anything about them. I found only datasheets for some of
the HLP antennas (mostly from TDK). Would it be a start to search about
log-periodic antennas and adapt the information? What would be the
difference between them?

Maybe it would sound like a stupid question to all of you, but I really
don't know where to start. Can someone give me a bit of help?

Thank you.

--
Little_skip


Hello,

I don't know your background and to what depth the article should go,
but I assume that you have a background in Electronic Engineering.

It is good to know some properties and design trade offs for the
normal LP antenna (this requires basic knowledge on antennas). There
are several design parameters that sets maximum and minimum frequency
range and gain.

The "Hybrid" part relates to a merge between a flat dipole and the LP.
At the low end of the useful frequency range of the HLP, the antenna
radiation pattern behaves like a dipole antenna.

Simulation is a good way to "see" the effect of various LP designs.

The second challenge for you will be the calibration (I assume gain
calibration). Calibrating for gain does not only involve antennas, but
also EM wave propagation, transmission lines and a certain attitude
towards the measuring results. Also here, simulation is a good way to
"see" the effect of (small) changes in your test setup for
calibration.

You might consider hiring an expert to set you on the right track. It
may save you lots of time.

Best regards,

Wim
PA3DJS
www.tetech.nl
with abc the mail address is valid.



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