Question, Colinear design Error?
 

Hi all,
I looked at this site and don't see a dimension for the loops,
Ok maybe not an error, but shouldn't the loops have a specific
physical length. Please see the antenna at;

http://martybugs.net/wireless/collinear.cgi

Mike

Question, Colinear design Error?
 

In article ,
amdx wrote:

Hi all,
I looked at this site and don't see a dimension for the loops,

Follow the "bent as detailed here" link.

Ok maybe not an error, but shouldn't the loops have a specific
physical length.

According to that link, the loops are 10mm in diameter, or 10*pi mm around.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Question, Colinear design Error?
 

"Dave Platt" wrote in message
...
In article ,
amdx wrote:

Hi all,
I looked at this site and don't see a dimension for the loops,

Follow the "bent as detailed here" link.

Ok maybe not an error, but shouldn't the loops have a specific
physical length.

According to that link, the loops are 10mm in diameter, or 10*pi mm
around.

Thanks, Dave
So 10mm*pi is equal to about 1/4 wavelength at 2.437Ghz. I have
spent
about twenty minutes with google and I don't find any info saying that is
the proper
length to phase the sections. What do you think?
Mike

Question, Colinear design Error?
 

"amdx" wrote in message
...

"Dave Platt" wrote in message
...
In article ,
amdx wrote:

Hi all,
I looked at this site and don't see a dimension for the loops,

Follow the "bent as detailed here" link.

Ok maybe not an error, but shouldn't the loops have a specific
physical length.

According to that link, the loops are 10mm in diameter, or 10*pi mm
around.

Thanks, Dave
So 10mm*pi is equal to about 1/4 wavelength at 2.437Ghz. I have
spent
about twenty minutes with google and I don't find any info saying that is
the proper
length to phase the sections. What do you think?
Mike


Hi Mike

If you wanted -- you could replace the "loops" with quarterwave stubs to
separate successive halfwave radiators.

Jerry

Question, Colinear design Error?
 

In article ,
amdx wrote:

According to that link, the loops are 10mm in diameter, or 10*pi mm
around.

Thanks, Dave
So 10mm*pi is equal to about 1/4 wavelength at 2.437Ghz. I have
spent
about twenty minutes with google and I don't find any info saying that is
the proper
length to phase the sections. What do you think?

There are no doubt multiple ways to construct such an antenna. A
simple approach would be to use halfwave-long vertical radiating
sections, and shorted quarter-wavelength stubs (sticking out to the
side, or curled into a near-circular shape) as phasing sections. This
would result in "stacked" half-wave radiators. The "Super J-pole"
uses this approach.

Another approach for collinears is to use 1/2-wave or 5/8-wave
radiating sections, and lumped inductors as phasing sections. An
example of this is the Hustler G7-144 (three stacked 5/8 radiators,
with lumped inductors between them).

I haven't gone over the design that you posted in detail, but it
wouldn't surprise me greatly if the main radiating sections were
around 5/8 wavelength, and the phasing loops have enough inductance to
create the appropriate phase relationships. Since the phasing
sections are inductive loops rather than shorted transmission lines,
one would not necessarily expect the "radiating section length, plus
total length of wire in the phasing section" to add up to precisely 1
wavelength.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!