Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old October 15th 06, 11:19 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Oct 2006
Posts: 46
Default 2 meter yagi

Who sells them with the most bang for the buck?


  #2   Report Post  
Old October 16th 06, 12:28 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 162
Default 2 meter yagi

Depends what you want. Are you going to use a small Yagi for FM work or
a long boom Yagi for SSB/CW? If you want something fairly simple, a
homemade 6 or 8 element Yagi is fairly simple. Otherwise, for some
serious weak signal work, the K1FO designs are quite commonly used.
Directive Systems sell them... http://www.directivesystems.com/antenna4.htm

Hope that helps!

Scott
N0EDV

Merlin-7 KI4ILB wrote:

Who sells them with the most bang for the buck?


  #3   Report Post  
Old October 16th 06, 12:40 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Oct 2006
Posts: 46
Default 2 meter yagi

What design plans would you use?

Thanks
joe

"Scott" wrote in message
.. .
Depends what you want. Are you going to use a small Yagi for FM work or
a long boom Yagi for SSB/CW? If you want something fairly simple, a
homemade 6 or 8 element Yagi is fairly simple. Otherwise, for some
serious weak signal work, the K1FO designs are quite commonly used.
Directive Systems sell them...

http://www.directivesystems.com/antenna4.htm

Hope that helps!

Scott
N0EDV



  #4   Report Post  
Old October 16th 06, 01:29 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Oct 2006
Posts: 134
Default 2 meter yagi

"Merlin-7 KI4ILB" wrote in message
...
What design plans would you use?

Thanks
joe


Are you an Internet only type of person?

The original design was perfected by Steve Powlishen, K1FO, who spent
hundreds of hours optimizing yagi designs on a high powered Hewlett Packard
computer.
He started with some computer optimized designs of Tom Kirby, W1EJ, (SK) who
was using computer software developed at Ohio State University. W1EJ had
came up with many excellent VHF long yagi designs.

The finished K1FO designs were carefully checked out in the real world by
K1FO to ensure accuracy of the design effort. His efforts have produced an
exceptional design with maximum gain very close to the maximum amount
possible, while keeping side lobes, (particularly those of the H-plane) at a
very low level. The net result is broad bandwidth, wide beamwidth, and clean
lobe structure.
Clean H-plane patterns translate to efficient stacking with maximum possible
gain and manageable array side lobes.

The design has been published in MANY printings of the ARRL Handbook.

gb


  #5   Report Post  
Old October 16th 06, 12:22 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 162
Default 2 meter yagi

If you don't mind having a little less gain than is ultimately possible
by using an antenna modeling program, the NBS (Nation Bureau of
Standards) designs are pretty straight-forward. For a 6 element Yagi,
here is element lengths and spacings for building with insulated
elements (insulated from the boom, so I would use wood, 1" X 2" X 8.5')

Lengths:
Reflector = 3' 4"
Driven = 3' 2-3/16"
Dir 1 = 3' 7/8"
Dir 2 = 3' 7/16"
Dir 3 = 3' 7/16"
Dir 4 = 3' 7/8"

Spacing:
Ref to Driven = (187.2/Fc) X 12
Spacing between all other elements = (234/Fc) X 12
where Fc is the design center frequency in MHz, ie 146 for the center of
the FM portion). The spacing calculations give the answer in inches.

Then you need to feed it. I use delta matches. Are you good at
qrz.com? If so I can send you a drawing of the feed to get you started
(but you would need an SWR meter that works at 2M to get it adjusted).

Scott
N0EDV

Merlin-7 KI4ILB wrote:
What design plans would you use?

Thanks
joe

"Scott" wrote in message
.. .

Depends what you want. Are you going to use a small Yagi for FM work or
a long boom Yagi for SSB/CW? If you want something fairly simple, a
homemade 6 or 8 element Yagi is fairly simple. Otherwise, for some
serious weak signal work, the K1FO designs are quite commonly used.
Directive Systems sell them...


http://www.directivesystems.com/antenna4.htm

Hope that helps!

Scott
N0EDV






  #6   Report Post  
Old October 18th 06, 01:54 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 230
Default 2 meter yagi

Scott wrote:

If you don't mind having a little less gain than is ultimately possible
by using an antenna modeling program, the NBS (Nation Bureau of
Standards) designs are pretty straight-forward. For a 6 element Yagi,
here is element lengths and spacings for building with insulated
elements (insulated from the boom, so I would use wood, 1" X 2" X 8.5')

Lengths:
Reflector = 3' 4"
Driven = 3' 2-3/16"
Dir 1 = 3' 7/8"
Dir 2 = 3' 7/16"
Dir 3 = 3' 7/16"
Dir 4 = 3' 7/8"

Spacing:
Ref to Driven = (187.2/Fc) X 12
Spacing between all other elements = (234/Fc) X 12
where Fc is the design center frequency in MHz, ie 146 for the center of
the FM portion). The spacing calculations give the answer in inches.

Then you need to feed it. I use delta matches. Are you good at
qrz.com? If so I can send you a drawing of the feed to get you started
(but you would need an SWR meter that works at 2M to get it adjusted).

Scott
N0EDV


NBS yagis were quite horrible actually. Not good gain, horrid
bandwidth, high sensitivity to build errors , crummy patterns compared
to anything since the early 90's. Don't bother.

tom
K0TAR

  #7   Report Post  
Old October 18th 06, 12:06 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 162
Default 2 meter yagi

I won't debate the differences in patterns, as I have no data on the
patterns for the NBS designs. In the ones I've built, gains measured
were pretty close to what they claimed and the claimed gains of the K1FO
style antennas from Directive Systems
http://www.directivesystems.com/antenna4.htm (for the same number of
elements) is usually within a quarter to a half of a dB of the claimed
gains of the NBS designs. I didn't notice a high sensitivity to build
errors. I used the design lengths and diameters of the elements on a
wood boom. On my 222 version, I used the T match (same thing as the
K1FO designs) and all I had to do was shorten the driven element to get
zero reflected power (which was expected since you need to make the
driven capacitive to tune out the inductance of the matching rods). Not
sure what you mean by horrid bandwidth...are the NBS designs too narrow
or too wide? Again, I've never noticed that as being a problem because
I only use my (222 for example) antenna from about 222.100 to 222.150.

Scott
N0EDV

Tom Ring wrote:
Scott wrote:

If you don't mind having a little less gain than is ultimately
possible by using an antenna modeling program, the NBS (Nation Bureau
of Standards) designs are pretty straight-forward.



NBS yagis were quite horrible actually. Not good gain, horrid
bandwidth, high sensitivity to build errors , crummy patterns compared
to anything since the early 90's. Don't bother.

tom
K0TAR

  #8   Report Post  
Old October 18th 06, 02:01 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 230
Default 2 meter yagi

Scott wrote:

If you don't mind having a little less gain than is ultimately possible
by using an antenna modeling program, the NBS (Nation Bureau of
Standards) designs are pretty straight-forward. For a 6 element Yagi,
here is element lengths and spacings for building with insulated
elements (insulated from the boom, so I would use wood, 1" X 2" X 8.5')

Lengths:
Reflector = 3' 4"
Driven = 3' 2-3/16"
Dir 1 = 3' 7/8"
Dir 2 = 3' 7/16"
Dir 3 = 3' 7/16"
Dir 4 = 3' 7/8"

Spacing:
Ref to Driven = (187.2/Fc) X 12
Spacing between all other elements = (234/Fc) X 12
where Fc is the design center frequency in MHz, ie 146 for the center of
the FM portion). The spacing calculations give the answer in inches.

Then you need to feed it. I use delta matches. Are you good at
qrz.com? If so I can send you a drawing of the feed to get you started
(but you would need an SWR meter that works at 2M to get it adjusted).

Scott
N0EDV


Sorry, I didn't give an alternatives in my previous email. Please see
the K1FO series in the ARRL antenna books. They are among absolutely
the best possible, very replicable,, low build sensitivity, and fairly
short to very long boom plans are available.

If you do not have one of the ARRL Antenna books available, I, or others
here, have copies as needed.

tom
K0TAR

  #9   Report Post  
Old October 18th 06, 11:05 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Oct 2006
Posts: 46
Default 2 meter yagi

Thanks for all the information everyone...
The only ARRL antenna book I have is the one on wire antennas, If you could
suggest one that covers yagi antennas in detail, I am sure they still sell
it. I think that I could build one a lot cheaper than buying one and learn
something at the same time.

I would like the best gain possible (who wouldn't) However, I need
something that has the smallest lobe(s) off the sides and back. (I know the
two more or less coincide with each to a large degree.

To give you an idea of what I am trying to do...I have some land in
Richlands NC. I am a member of several ham clubs in the Charleston,SC area
that has repeaters fairly close to the SC,NC state lines. I would like to be
able to make it into one of those repeaters from Richlands, NC. (that may
only work when the bands open up every now and again)
I do not want to key up every repeater on the same freq. to the sides or
the back of the antenna.
So I bow down to the elmers and those who can point me in the right
direction. BTW. the antenna will be at least 60' high but possibley up to
110' high depending on tower funds when I move.

Im good at QRZ and ARRL
Thanks again
Joe KI4ILB
Solar powered ham radio


"Tom Ring" wrote in message
.. .
Scott wrote:

If you don't mind having a little less gain than is ultimately possible
by using an antenna modeling program, the NBS (Nation Bureau of
Standards) designs are pretty straight-forward. For a 6 element Yagi,
here is element lengths and spacings for building with insulated
elements (insulated from the boom, so I would use wood, 1" X 2" X 8.5')

Lengths:
Reflector = 3' 4"
Driven = 3' 2-3/16"
Dir 1 = 3' 7/8"
Dir 2 = 3' 7/16"
Dir 3 = 3' 7/16"
Dir 4 = 3' 7/8"

Spacing:
Ref to Driven = (187.2/Fc) X 12
Spacing between all other elements = (234/Fc) X 12
where Fc is the design center frequency in MHz, ie 146 for the center of
the FM portion). The spacing calculations give the answer in inches.

Then you need to feed it. I use delta matches. Are you good at
qrz.com? If so I can send you a drawing of the feed to get you started
(but you would need an SWR meter that works at 2M to get it adjusted).

Scott
N0EDV


Sorry, I didn't give an alternatives in my previous email. Please see
the K1FO series in the ARRL antenna books. They are among absolutely
the best possible, very replicable,, low build sensitivity, and fairly
short to very long boom plans are available.

If you do not have one of the ARRL Antenna books available, I, or others
here, have copies as needed.

tom
K0TAR



  #10   Report Post  
Old October 16th 06, 02:05 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 702
Default 2 meter yagi


"Scott" wrote in message
.. .
Depends what you want. Are you going to use a small Yagi for FM work or a
long boom Yagi for SSB/CW? If you want something fairly simple, a
homemade 6 or 8 element Yagi is fairly simple. Otherwise, for some
serious weak signal work, the K1FO designs are quite commonly used.
Directive Systems sell them...
http://www.directivesystems.com/antenna4.htm

Hope that helps!

Scott
N0EDV


Now you tell me. I just ordered 2 beams from M-Square, one for 432 and one
for 144. Wish I had the K1FO antennas as I had one for 432 and it worked
very well. I did not know anyone had picked up the K1FO design after he
became a SK.





Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Odd signal meter phenomenon Telamon Shortwave 0 November 25th 05 04:58 PM
SWR meter vs TLI Reg Edwards Antenna 179 September 9th 04 06:01 PM
SWR meter kaput? Thomas Antenna 5 August 13th 04 06:44 PM
Triplett 3423 meter movement help needed Sam Lloyd Equipment 4 March 26th 04 02:07 AM
Fwd: Bible Voice A04 Schedule RHF Shortwave 1 March 16th 04 11:50 AM


All times are GMT +1. The time now is 10:29 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017