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Brad June 17th 06 04:33 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
Hi,

Does anyone have a formula or know a technique for
converting an 11 meter 3 element yagi antenna into a
10 meter yagi (beam antenna)?

Thanks in advance, Brad

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[email protected] June 17th 06 06:00 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
Brad wrote:
Hi,

Does anyone have a formula or know a technique for
converting an 11 meter 3 element yagi antenna into a
10 meter yagi (beam antenna)?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.


Well, wouldn't it be 10/11 length of each element? Get a big wire
cutter and have at it.

GG


AZ Nomad June 17th 06 06:27 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
On 17 Jun 2006 10:00:19 -0700, wrote:


Brad wrote:
Hi,

Does anyone have a formula or know a technique for
converting an 11 meter 3 element yagi antenna into a
10 meter yagi (beam antenna)?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.


Well, wouldn't it be 10/11 length of each element? Get a big wire
cutter and have at it.


Don't forget to snip up the frame to pull the elements closer.



g. beat June 17th 06 08:40 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
"Brad" wrote in message
...
Hi,

Does anyone have a formula or know a technique for
converting an 11 meter 3 element yagi antenna into a
10 meter yagi (beam antenna)?

Thanks in advance, Brad


Brad -

First, What 11 meter beam is this? Manufacturer?
Did you know that many manufacturers have this information in their assembly
instructions?

Have your amateur radio license yet?
I provide assistance for licensed amateurs.

Google will lead you to answer.

gb



Jeff Liebermann June 17th 06 10:47 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
On Sat, 17 Jun 2006 15:33:56 GMT, (Brad) wrote:

Does anyone have a formula or know a technique for
converting an 11 meter 3 element yagi antenna into a
10 meter yagi (beam antenna)?


Sure. Take your current antenna dimensions and plug them into an
antenna modeling package such as:

4NEC2 (free)
http://home.ict.nl/~arivoors/

Eznec (free demo)
http://www.eznec.com

or any of those listed at:
http://www.si-list.org/swindex2.html

Insert your current antenna dimensions into the program and make sure
it works at 11 meters. Then, change the frequency to 10 meters and
run the optimizer.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#
http://802.11junk.com
#
http://www.LearnByDestroying.com AE6KS

DaveM June 18th 06 01:00 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
"Brad" wrote in message
...
Hi,

Does anyone have a formula or know a technique for
converting an 11 meter 3 element yagi antenna into a
10 meter yagi (beam antenna)?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.



The frequency difference might be insignificant if your antenna tuner can
accommodate the differences. The 10-meter band is lower in frequency than the
11-meter band, therefore all elements would have to be lengthened by a small
amount to get it exactly right. Google around for yagi antenna design software.
There are probably a number of freebies available.

I Googled for yagi antenna design and the second hit came up with
http://www.hamuniverse.com/yagibasics.html, which should give your answer.

Cheers!!

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some days you're the dog, some days the hydrant.



Geoffrey S. Mendelson June 18th 06 02:00 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
DaveM wrote:
The frequency difference might be insignificant if your antenna tuner can
accommodate the differences. The 10-meter band is lower in frequency than the
11-meter band, therefore all elements would have to be lengthened by a small
amount to get it exactly right.


Sorry, it's not. The eleven meter band, aka CB, is in the 27mHz range.
The 10m Ham band is 28.0 to 29.7 mHz, but most people don't use the
whole band. 28.0-28.3 is mostly CW (Morse code) because the U.S. prohibits
usage of voice signals there.

SSB and AM voice signals are legal in the rest of the band, but most often
they are found in the 28.5-29.0 range. FM voice is limited in the U.S.
to 29.0 and up, and FM repeaters use 29.5 to 29.6 for TRANSMISSION.

While it would be best to shorten all of the elements, and move them closer
together, it is really only necessary to shorten the driven element
(where the radio connects) and the director (the one in front of it).

You can do it simply by measuring them and cuting off the ends to make
them 27/28ths of the size they were.

Modeling the antenna with computer software would save you a lot of
time and trouble, or carefully modifying it by cutting and trying it
with an SWR meter or an antenna analyzer.

Keep in mind that you need a valid ham license in most countries
to transmit on 10 meters. If you do not have a license and are planing
to get one in the future, don't bother modifying it. The difference
in reception is not really worth it.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at
http://geoffstechno.livejournal.com/

Jeff Liebermann June 18th 06 05:20 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
(Geoffrey S. Mendelson) hath wroth:

DaveM wrote:
The frequency difference might be insignificant if your antenna tuner can
accommodate the differences. The 10-meter band is lower in frequency than the
11-meter band, therefore all elements would have to be lengthened by a small
amount to get it exactly right.


Sorry, it's not. The eleven meter band, aka CB, is in the 27mHz range.
The 10m Ham band is 28.0 to 29.7 mHz, but most people don't use the
whole band. 28.0-28.3 is mostly CW (Morse code) because the U.S. prohibits
usage of voice signals there.

SSB and AM voice signals are legal in the rest of the band, but most often
they are found in the 28.5-29.0 range. FM voice is limited in the U.S.
to 29.0 and up, and FM repeaters use 29.5 to 29.6 for TRANSMISSION.


I don't think the original poster is interested in becoming a ham and
using the 10 meter ham band allocations. My guess(tm) is that he's
interested in "freeband" radio. Freeband is located in between the
CB band and the 10 meter ham band from 27.410 to 28.000Mhz. Operation
in this area is strictly illegal, but that doesn't seem to prevent
Freeband operators from doing so, or seem to interest the FCC
enforcement burro. For example:
http://www.geocities.com/de2at462/

In most cases, scaling the yagi antenna elements without changing the
spacing is sufficient for such small changes in frequency. However,
the gamma match should also be adjusted for minimum VSWR, especially
if one is running an illegal high power amplifier. The pattern or
gain won't be optimized but good enough to function as a directional
antenna.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Geoffrey S. Mendelson June 18th 06 06:51 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 
Jeff Liebermann wrote:

I don't think the original poster is interested in becoming a ham and
using the 10 meter ham band allocations. My guess(tm) is that he's
interested in "freeband" radio. Freeband is located in between the
CB band and the 10 meter ham band from 27.410 to 28.000Mhz. Operation
in this area is strictly illegal, but that doesn't seem to prevent
Freeband operators from doing so, or seem to interest the FCC
enforcement burro. For example:


I assume nothing. Outside of the U.S. the bands are different, enforcement
is different,e tc. For example in the E.U., you can use a regular ham
radio on CB, no one seems to care about the power. FM and packet are
also common on CB.

Since I've been here in Israel (almost 10 years), I've never met a person
with a CB. I occasionaly scan through the bands, but I never hear anyone
on 2m, 10m, and CB.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at
http://geoffstechno.livejournal.com/

Michael Ware June 18th 06 10:11 PM

11 Meter to 10 Meter Yagi Antenna Conversion
 

"DaveM" wrote in message
. ..

The frequency difference might be insignificant if your antenna tuner can
accommodate the differences. The 10-meter band is lower in frequency than

the
11-meter band, therefore all elements would have to be lengthened by a

small
amount to get it exactly right. Google around for yagi antenna design

software.
There are probably a number of freebies available.

No, the higher the frequency, the shorter the wavelength.




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