[Antennas] Re: "J" poles - Wait A Minute!

Sun, 14 Jul 2002 19:16:43 +0200

   guys there's no such thing as a monopole with nothing else . We =
connect a
two terminal source (the transmitter) to something that MUST have also =
2
terminals . If one is the antenna, any antenna, then the second =
terminal of
the source must go to something, ground plane, counterpoise or what =
ever.
Current always flows beteween 2 (TWO!) points.the J-match section =
translates
the 50 ohms to a high impedance. One side matches the antenna while the
other is acting as storage capacitor (fringe capacitance) and reverses
charge peiodically to allow current flow.

-----Original Message-----
From: Dan Richardson [mailto:[email protected]]=20
Sent: Sunday, July 14, 2002 5:48 PM
To: Karl Kanalz; [email protected]
Subject: [Antennas] Re: "J" poles - Wait A Minute!

Karl,

God bless!

Finally, someone who understands!

The key is where and how the antenna (a =BD-wave monopole in this case) =
is
fed.

The statement that an end fed single =BD-wavelength element doesn't =
require a=20
counterpoise system to work well is not true!

Allow me to quote for "The Amateur Radio Vertical Antenna Handbook" by =
Paul=20
Lee, N6PL (SK);

"The claim that one does not need a ground system under a half wave=20
vertical radiator is true only if he is content to throw away from 40 =
to 80=20
percent of his radiated power in the form of earth losses."

N6PL goes on to say regarding the current conditions a the base of a =
=BD-wave=20
monopole (vertical)... "A thermocouple ammeter in the ground [radial] =
lead=20
at this point will read zero. However, don't be deceived by this=20
phenomenon, because the thermocouple ammeter in the antenna lead will =
also=20
read zero."

Many believe that because the current at the base portion of a =BD-wave =

monopole and its ground system is zero (or very near zero) radials are =
not=20
need. What they fail see is that the current is at a maxim point at a=20
distance of about 0.35 wavelengths from the base of the antenna. This =
the=20
distance where most of the ground losses occurs for =BD-wavelength =
monopoles.

Thanks for stepping in.

73
Danny

At 08:51 AM 7/14/2002 -0500, you wrote:
>Hey Guys,
>
>The word "dipole" means TWO poles - "di" equals TWO.
>
>The word "monopole" means ONE pole - "mono" equals ONE.
>
>Please don't confuse the two, especially when you're comparing feeding
>methods!
>
>Please keep the terminology straight!  A half-wave long "monopole" (a
>continuous strip of wire or tubing)
>Is NOT, repeat, NOT, a "dipole" !!  It's a half-wave long monopole and =

>that's it.....  how you choose to
>feed it is your question (problem).
>
>A half-wave length DIPOLE is another matter, along with the problems=20
>and
>supports of feeding it.
>
>Get your terminology correct, PLEASE!
>
>Thanks!
>
>Karl K  - W8TIF
>McKinney, Texas

--- StripMime Report -- processed MIME parts --- multipart/alternative
  text/plain (text body -- kept)
  text/html
The reason this message is shown is because the post was in HTML or had =
an
attachment. Attachments are not allowed. Please post in Plain-Text =
only.---
- - -=20

Your moderator for this list is:
Larry Wilson KE1HZ [email protected]
_______________________________________________
Antennas mailing list
[email protected] =
http://mailman.qth.net/mailman/listinfo/antennas

---
Incoming mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.375 / Virus Database: 210 - Release Date: 10/07/02
=20

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.375 / Virus Database: 210 - Release Date: 10/07/02
=20