quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH inspired me to build one. However, after doing some research, I have come up with two sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz. However, when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field. The only difference is this model calculates for a full turn as opposed to a half turn, but the lengths shouldn't be as different as it says. Under the QST model, I get a wavelength of 688mm, but under the website's model, it gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Monday, September 28, 2009 9:45 PM Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH inspired me to build one. However, after doing some research, I have come up with
two
sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz.
However,
when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field.
The
only difference is this model calculates for a full turn as opposed to a half turn, but the lengths shouldn't be as different as it says. Under the QST model, I get a wavelength of 688mm, but under the website's model, it gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
Hi Tim, KI6VBY
Read please the book "REFLECTION" Transmission Lines and Antennas by M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages 22-1 to 22-23 and also "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz" The AMSAT Journal May/June 2004 In a separate email I have sent to you both articles as an attachement.
73" de
i8CVS Domenico
I have a question along the same line. Is the QHA in the ARRL Satellite Handbook \ Antenna handbook, a good starting place?
Thanks, Frank B. KB1QZH
On Tue, Sep 29, 2009 at 11:17 AM, i8cvs [email protected] wrote:
----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Monday, September 28, 2009 9:45 PM Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH inspired me to build one. However, after doing some research, I have come up with
two
sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz.
However,
when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field.
The
only difference is this model calculates for a full turn as opposed to a half turn, but the lengths shouldn't be as different as it says. Under the QST model, I get a wavelength of 688mm, but under the website's model, it gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
Hi Tim, KI6VBY
Read please the book "REFLECTION" Transmission Lines and Antennas by M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages 22-1 to 22-23 and also "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz" The AMSAT Journal May/June 2004 In a separate email I have sent to you both articles as an attachement.
73" de
i8CVS Domenico
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi Frank, KB1QZH
The best starting point is the original article of the inventor of QHA i.e Walter Maxell, W2DU
In a separate email I have attached the above fundamental article.
73" de
i8CVS Domenico
----- Original Message ----- From: "Franklyn A. Ballentine, jr" [email protected] To: "i8cvs" [email protected] Cc: "AMSAT-BB" [email protected] Sent: Tuesday, September 29, 2009 6:45 PM Subject: Re: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
I have a question along the same line. Is the QHA in the ARRL Satellite Handbook \ Antenna handbook, a good starting place?
Thanks, Frank B. KB1QZH
On Tue, Sep 29, 2009 at 11:17 AM, i8cvs [email protected] wrote:
----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Monday, September 28, 2009 9:45 PM Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH
inspired
me to build one. However, after doing some research, I have come up with
two
sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz.
However,
when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field.
The
only difference is this model calculates for a full turn as opposed to a half turn, but the lengths shouldn't be as different as it says. Under
the
QST model, I get a wavelength of 688mm, but under the website's model, it gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
Hi Tim, KI6VBY
Read please the book "REFLECTION" Transmission Lines and Antennas by M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages 22-1 to 22-23 and also "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz"
The
AMSAT Journal May/June 2004 In a separate email I have sent to you both articles as an attachement.
73" de
i8CVS Domenico
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
The most comprehensive info on QFH antennas is the Microwave Journal December 1970 Pgs 49-54 By CC Kilgus.
Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of i8cvs Sent: Wednesday, September 30, 2009 5:35 AM To: AMSAT-BB; Franklyn A. Ballentine, jr Subject: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
Hi Frank, KB1QZH
The best starting point is the original article of the inventor of QHA i.e Walter Maxell, W2DU
In a separate email I have attached the above fundamental article.
73" de
i8CVS Domenico
----- Original Message ----- From: "Franklyn A. Ballentine, jr" [email protected] To: "i8cvs" [email protected] Cc: "AMSAT-BB" [email protected] Sent: Tuesday, September 29, 2009 6:45 PM Subject: Re: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
I have a question along the same line. Is the QHA in the ARRL Satellite Handbook \ Antenna handbook, a good starting place?
Thanks, Frank B. KB1QZH
On Tue, Sep 29, 2009 at 11:17 AM, i8cvs [email protected] wrote:
----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Monday, September 28, 2009 9:45 PM Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH
inspired
me to build one. However, after doing some research, I have come up with
two
sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz.
However,
when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field.
The
only difference is this model calculates for a full turn as opposed to a half turn, but the lengths shouldn't be as different as it says. Under
the
QST model, I get a wavelength of 688mm, but under the website's model, it gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
Hi Tim, KI6VBY
Read please the book "REFLECTION" Transmission Lines and Antennas by M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages 22-1 to 22-23 and also "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz"
The
AMSAT Journal May/June 2004 In a separate email I have sent to you both articles as an attachement.
73" de
i8CVS Domenico
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
__________ Information from ESET NOD32 Antivirus, version of virus signature database 4468 (20090929) __________
The message was checked by ESET NOD32 Antivirus.
__________ Information from ESET NOD32 Antivirus, version of virus signature database 4471 (20090930) __________
The message was checked by ESET NOD32 Antivirus.
Hi Art, KC6UQH
I would like to receive from you copy of the Microwave Journal December 1970 Pgs 49-54 By Doctor CC Kilgus about the QFH Antennas.
Tanks
73" de
i8CVS Domenico
----- Original Message ----- From: "Art McBride" [email protected] To: "'i8cvs'" [email protected]; "'AMSAT-BB'" [email protected]; "'Franklyn A. Ballentine, jr'" [email protected] Sent: Thursday, October 01, 2009 7:09 AM Subject: RE: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
The most comprehensive info on QFH antennas is the Microwave Journal December 1970 Pgs 49-54 By CC Kilgus.
Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of i8cvs Sent: Wednesday, September 30, 2009 5:35 AM To: AMSAT-BB; Franklyn A. Ballentine, jr Subject: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
Hi Frank, KB1QZH
The best starting point is the original article of the inventor of QHA i.e Walter Maxell, W2DU
In a separate email I have attached the above fundamental article.
73" de
i8CVS Domenico
----- Original Message ----- From: "Franklyn A. Ballentine, jr" [email protected] To: "i8cvs" [email protected] Cc: "AMSAT-BB" [email protected] Sent: Tuesday, September 29, 2009 6:45 PM Subject: Re: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
I have a question along the same line. Is the QHA in the ARRL Satellite Handbook \ Antenna handbook, a good starting place?
Thanks, Frank B. KB1QZH
On Tue, Sep 29, 2009 at 11:17 AM, i8cvs [email protected] wrote:
----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Monday, September 28, 2009 9:45 PM Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH
inspired
me to build one. However, after doing some research, I have come up
with
two
sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz.
However,
when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field.
The
only difference is this model calculates for a full turn as opposed to
a
half turn, but the lengths shouldn't be as different as it says. Under
the
QST model, I get a wavelength of 688mm, but under the website's model,
it
gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
Hi Tim, KI6VBY
Read please the book "REFLECTION" Transmission Lines and Antennas by M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages 22-1 to 22-23 and also "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz"
The
AMSAT Journal May/June 2004 In a separate email I have sent to you both articles as an attachement.
73" de
i8CVS Domenico
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
__________ Information from ESET NOD32 Antivirus, version of virus
signature
database 4468 (20090929) __________
The message was checked by ESET NOD32 Antivirus.
__________ Information from ESET NOD32 Antivirus, version of virus
signature
database 4471 (20090930) __________
The message was checked by ESET NOD32 Antivirus.
http://polysat.calpoly.edu/earthstation/documents/helix-microwavejournal-dec... -- Bryan Klofas, KF6ZEO
i8cvs wrote:
Hi Art, KC6UQH
I would like to receive from you copy of the Microwave Journal December 1970 Pgs 49-54 By Doctor CC Kilgus about the QFH Antennas.
Tanks
73" de
i8CVS Domenico
----- Original Message ----- From: "Art McBride" [email protected] To: "'i8cvs'" [email protected]; "'AMSAT-BB'" [email protected]; "'Franklyn A. Ballentine, jr'" [email protected] Sent: Thursday, October 01, 2009 7:09 AM Subject: RE: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
The most comprehensive info on QFH antennas is the Microwave Journal December 1970 Pgs 49-54 By CC Kilgus.
Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of i8cvs Sent: Wednesday, September 30, 2009 5:35 AM To: AMSAT-BB; Franklyn A. Ballentine, jr Subject: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
Hi Frank, KB1QZH
The best starting point is the original article of the inventor of QHA i.e Walter Maxell, W2DU
In a separate email I have attached the above fundamental article.
73" de
i8CVS Domenico
----- Original Message ----- From: "Franklyn A. Ballentine, jr" [email protected] To: "i8cvs" [email protected] Cc: "AMSAT-BB" [email protected] Sent: Tuesday, September 29, 2009 6:45 PM Subject: Re: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
I have a question along the same line. Is the QHA in the ARRL Satellite Handbook \ Antenna handbook, a good starting place?
Thanks, Frank B. KB1QZH
On Tue, Sep 29, 2009 at 11:17 AM, i8cvs [email protected] wrote:
----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Monday, September 28, 2009 9:45 PM Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
Hi All,
The house I just bought precludes me from even using my arrow inside as there must be something un-RF friendly in the walls. Therefore, I was looking for a roof antenna and the October QST article on the QFH
inspired
me to build one. However, after doing some research, I have come up
with
two
sets of design specs and I'm unsure which one is correct.
I converted everything from you're the 146Mhz QST model to 436Mhz.
However,
when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
The values it puts out are different in the "compensated length" field.
The
only difference is this model calculates for a full turn as opposed to
a
half turn, but the lengths shouldn't be as different as it says. Under
the
QST model, I get a wavelength of 688mm, but under the website's model,
it
gives me a "compensated wavelength" of 729mm.
The values I used to calculate are:
436
1
1
15
2
.23
Can anyone tell me which specs to use and/or explain this compensated wavelength issue?
Thank you,
Tim
KI6VBY
Hi Tim, KI6VBY
Read please the book "REFLECTION" Transmission Lines and Antennas by M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages 22-1 to 22-23 and also "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz"
The
AMSAT Journal May/June 2004 In a separate email I have sent to you both articles as an attachement.
73" de
i8CVS Domenico
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
__________ Information from ESET NOD32 Antivirus, version of virus
signature
database 4468 (20090929) __________
The message was checked by ESET NOD32 Antivirus.
__________ Information from ESET NOD32 Antivirus, version of virus
signature
database 4471 (20090930) __________
The message was checked by ESET NOD32 Antivirus.
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (5)
-
Art McBride -
Bryan Klofas -
Franklyn A. Ballentine, jr -
i8cvs -
Tim Goodrich