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.

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

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.

"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

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

"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.

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/

(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

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/

"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.

In message , Geoffrey S.
Mendelson writes
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.

You certainly can NOT legally use "a regular ham radio on CB" (at least
not in the UK), even if you keep to the 4W power limit. CB radios have
to be type approved to be legal.

If you are a licensed radio amateur, you can, of course, modify a legal
CB radio for use on the 10m band (or, for that matter, any other amateur
band). However, the authorities are (or were) a little difficult about
modifying illegal CB radios for amateur use, on the grounds that they
were not approved, so could not have been legally imported into the UK.
No import duty could have been paid, so they must have been smuggled
here.

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.


Don't know why you've never heard anyone on 2m or 10m (but I can't speak
for CB).

As for the original question, I don't see why an 11m beam can not be
trimmed a little to move it up into the 10m band. I doubt if you will
need to reduce the spacing between the elements.

Cheers.
Ian.


--

(Geoffrey S. Mendelson) hath wroth:

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.

You assumed that the original poster wanted to operate in the 10 meter
ham band, and not between the ham band and CB.

Outside of the U.S. the bands are different, enforcement
is different,e tc.

True. World wide, the area between 27.410 to 28.000MHz is either
meteorological, or commercial ISM service. See:
http://www.fcc.gov/oet/spectrum/table/fcctable.pdf
Page 15. The 2 columns are for international and US allocations. Note
that none of them include Part 95 (CB) or part 97 (Ham). Your
non-assumption is wrong.

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.

I do PSK31 on CB just to see if it can get through the interference.
Seems to work quite well. Just because nobody cares, or nobody
enforces the rules, doesn't make it legal.

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.

See:
http://w3.iarc.org/repeater/
http://www.iarc.org/repeater/LIST.htm
I was in Haifa in Dec 2000, and found it fully occupied by jammers
from both sides of the political spectrum. Has the repeater network
been abandoned? Perhaps if you listen during one of the weekly nets:
http://w3.iarc.org/nets/nets.html

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

Ian Jackson wrote:
You certainly can NOT legally use "a regular ham radio on CB" (at least
not in the UK), even if you keep to the 4W power limit. CB radios have
to be type approved to be legal.

The U.K.may be the exception. I have seen articles in radio magazines back
when I could get them, showing ham radios used on CB in continental
Europe, Spain, France, the Netherlands. If it was legal or not, the articles
and pictures were there.


Don't know why you've never heard anyone on 2m or 10m (but I can't speak
for CB).

There is a 2m repeater here, but if it used more than an hour a week I'd
be surprised. I've monitored it randomly and occasionaly for several days
at a time, and it is unused. There may be more activity in the north, but
not here. When I moved here in '96 the local repeater id'ed as
"This is R1 Jerusalem open to all" in English and this is R1 Jerusalem
in Hebrew. Now there is just an occasional high speed CW ID and often that's
all I hear the entire day.

Ten meters is even less used. I can't hear any repeaters, maybe in a few
years when the sunspots are back. On the SSB/CW end of the band nothing.
40 and 20 are busy sometimes. Propigation varies on 20, sometimes
nothing, sometimes open. When it is open it's usually around sunrise/sunset
and you can hear the band following the Sun.

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" wrote in message
.. .

"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.



Yes, of course you are all correct, and I was totally wrong. I know better...
just don't know what happened to my thinking before I started typing.


--
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.