Hi all,

I've been away from ham radio for quite some time, and I am looking to
get my ht up and running. I want to make a J-pole.

Although I have found some plans to do so, I was looking more for the
science behind it.

I see that the stub is 1/4 wave and the other side is 1/2 or 3/4.

I forget the formula to find the wavelength. Was it the freq divided
by 468 or 234?


any help would be great.

kb2tfa

See BuxCom at URL:
http://www.commparts.com/antutorial.htm#2mjpole

Also URL:
http://www.cmara.org/N1WAS1.htm


wrote in message
oups.com...
Hi all,

I've been away from ham radio for quite some time, and I am looking to
get my ht up and running. I want to make a J-pole.

Although I have found some plans to do so, I was looking more for the
science behind it.

I see that the stub is 1/4 wave and the other side is 1/2 or 3/4.

I forget the formula to find the wavelength. Was it the freq divided
by 468 or 234?


any help would be great.

kb2tfa

wrote in message
oups.com...
Hi all,

I've been away from ham radio for quite some time, and I am looking to
get my ht up and running. I want to make a J-pole.

Although I have found some plans to do so, I was looking more for the
science behind it.

I see that the stub is 1/4 wave and the other side is 1/2 or 3/4.

I forget the formula to find the wavelength. Was it the freq divided
by 468 or 234?


any help would be great.

kb2tfa

Try looking in wikipedia for Wavelength.

wrote:
I forget the formula to find the wavelength. Was it the freq divided
by 468 or 234?

Wavelength is 984 divided by the frequency. 468/f is the
length of a 1/2WL dipole and 234/f is the length of a
1/4WL monopole both taking end effects into account.
--
73, Cecil http://www.w5dxp.com

"fergus" wrote in message
...
On Sat, 17 Feb 2007 20:25:07 GMT, Cecil Moore
wrote:

wrote:
I forget the formula to find the wavelength. Was it the freq divided
by 468 or 234?

Wavelength is 984 divided by the frequency. 468/f is the
length of a 1/2WL dipole and 234/f is the length of a
1/4WL monopole both taking end effects into account.

I thought wavelength was speed of light divided by frequency. ie. 3 x
10^8/freq. Or is the 984 in non SI units?


--

Fergus

no..in US they have strange formulas involving feets and inches... (sigh)
nothing to do with established SI

cheers,

On 17 Feb, 12:49, "christine" wrote:
"fergus" wrote in message

...





On Sat, 17 Feb 2007 20:25:07 GMT, Cecil Moore
wrote:

wrote:
I forget the formula to find the wavelength. Was it the freq divided
by 468 or 234?

Wavelength is 984 divided by the frequency. 468/f is the
length of a 1/2WL dipole and 234/f is the length of a
1/4WL monopole both taking end effects into account.

I thought wavelength was speed of light divided by frequency. ie. 3 x
10^8/freq. Or is the 984 in non SI units?

--

Fergus

no..in US they have strange formulas involving feets and inches... (sigh)
nothing to do with established SI

cheers,- Hide quoted text -

- Show quoted text -

Christine,
when I was young I went to the tool room in East London and asked
for 1 inch round by 6 foot and I was admonished up and down dale for
using the measurement inches. I went back to my lathe and worked it
out all again.
At the tool room I asked for 25mm by 2 metres length of steel only to
find out it only came in six foot lengths! Go to the top of the hill
in Greenwich park at the old observatory and on the wall you will see
examples of lengths from the old days so it was you that started this
mess.
By the way we don't have dual carrageways over here either and we
drive on the other side of the road. I understand Sweden has changed
over now, cars changed over on Sunday and trucks changed over the
following day. That week end is still known as black Sunday I
understand.
Art
on the other side of the pond

On Sat, 17 Feb 2007 22:49:46 +0200, "christine"
wrote:

no..in US they have strange formulas involving feets and inches... (sigh)
nothing to do with established SI

We also inherited the speed of light as 1.8x10^14 Furlongs per
Fortnight.

73's
Richard Clark, KB7QHC

On Sat, 17 Feb 2007 13:27:19 -0800, Richard Clark
wrote:

1.8x10^14 Furlongs
actually
1.8x10^12 Furlongs per fortnight

73's
Richard Clark, KB7QHC

fergus wrote:
I thought wavelength was speed of light divided by frequency. ie. 3 x
10^8/freq. Or is the 984 in non SI units?

It's actually 983.572 and it's in English units
based on the "standard" length of the foot of
one of the British kings.
--
73, Cecil http://www.w5dxp.com

christine wrote:
no..in US they have strange formulas involving feets and inches...

Strange? - It's the *English* system that we
adopted from our Mother Country.
--
73, Cecil http://www.w5dxp.com