Choke /BALUN
 

:Cecil,

I will start a little long as this is a peimo piece of 2" dia brass.
According to swr-freq by R. J. Edwards, the 2" dia sleave is about 50
ohms
for the 1/4 wave. 146 mhz, 51.1 ohms, jXin 0.0 .

My thaught is with the 1"mast inside of the sleave (insulated and
centered only connected at the top) what does the added capacitance do
to the sleave lenght?

And RFS does not have the old cutting charts for the Phelps Dodge PD83,
I tried that.

"Will" wrote:

How do you figure the lower "coaxial sleave" dimentions.
Cecil Moore wrote
It's usually 1/4WL long. The theory is to turn that 1/4WL of
feedline into a transmission line where the currents on the
outside of the original shield are balanced by the inside
shield on the sleeve which balances the antenna currents.
It functions over a certain single bandwidth.

Choke /BALUN
 

Try Tools | Options | Compose | News: Font Settings

"Cecil Moore" wrote in message
. com...
"Owen Duffy" wrote:
What's with the HTML format Cecil?

I've switched over from Netscape to Outlook Express and have
no idea what I am doing. I can't seem to get Outlook Express
to compose anything in Courier fixed font.
--
73, Cecil http://www.qsl.net/w5dxp

Choke /BALUN
 

"Will" wrote:
My thaught is with the 1"mast inside of the sleave (insulated and
centered only connected at the top) what does the added capacitance do
to the sleave lenght?

I'm sorry, I don't know what the velocity factor would be
in that configuration. If you sampled the common mode
current and tuned the frequency for a minimum, it might
give you an idea of the velocity factor.
--
73, Cecil http://www.qsl.net/w5dxp

Choke /BALUN
 

"John, N9JG" wrote:
Try Tools | Options | Compose | News: Font Settings

Of course, I have set the font to Courier but right now, even
though I have "Plain Text" selected, the composing font is
Times New Roman. If I select "Rich Text", then it will
compose in Courier but that is HTML. I once forgot to switch
to plain text before sending and it apparently posted HTML.
--
73, Cecil http://www.qsl.net/w5dxp

Choke /BALUN
 

I've gotten a few emails asking how a 1/4WL wire stub can be
used as a balun on a single band like 2m. Just connect the
wire to the element driven by the coax center conductor and
connect the other end to the braid 1/4WL down the coax. In
fixed font:

|
|
| Dipole
|
|
+====================================coax braid

+------------------------------------coax center conductor
|
| ===================+==============coax braid
| spacing |
+---------------------+
| 1/4WL stub
|

The current at the feedpoint sees a very high impedance looking
back down the *outside* braid of the feedline because it is looking
into a shorted 1/4WL stub. Often, a piece of similar coax is used
for the 1/4WL stub.
--
73, Cecil http://www.qsl.net/w5dxp

Choke /BALUN
 

Cecil Moore wrote:
"Owen Duffy" wrote:

What's with the HTML format Cecil?


I've switched over from Netscape to Outlook Express and have
no idea what I am doing. I can't seem to get Outlook Express
to compose anything in Courier fixed font.


Outlook Express? Say it ain't so Cecil!!


- 73 de Mike KB3EIA -

Choke /BALUN
 

"Mike Coslo" wrote:
Outlook Express? Say it ain't so Cecil!!

I was running Netscape but Netscape 8.1 doesn't do newsgroups.
Someone recommended Thunderbird. Comments?
--
73, Cecil http://www.qsl.net/w5dxp

Choke /BALUN
 

This reply IS useing Thunderbird (and quite
stable, too-- Jim NN7K

Cecil Moore wrote:
"Mike Coslo" wrote:

Outlook Express? Say it ain't so Cecil!!


I was running Netscape but Netscape 8.1 doesn't do newsgroups.
Someone recommended Thunderbird. Comments?

Choke /BALUN
 

Jim - NN7K wrote:
This reply IS useing Thunderbird (and quite stable, too-- Jim NN7K

OK, I just downloaded Thunderbird and it looks pretty good.
--
73, Cecil http://www.qsl.net/w5dxp