Works great. "J-pole" is a half-wave dipole, end fed (which is a voltage
loop) through a quarter wave transmission line shorted at the bottom. To
form this mental image: draw a horizontal dipole, and then draw the vertical
1/4 wave feedline. Then draw the same but with a vertical dipole -- and you
have a "J-pole".
That said, they *do* get big. I've built them for 10 meters and it is a
great Field Day or camping antenna because a rock, a string, and a handy
tree limb is all it takes to hoist it. You could build one for 80 meters,
but you'd need one heck of a tree and a dang good arm....
Could probably work out a Rohn stack that did it. But that much tower is
also 3/4's of a four square, which has gain (hopefully) and f/b, so the
money might be better spent on that.
73, Dave N6NZ
-----Original Message-----
From: Donald E. Stiles [mailto:goodnews@mail.cmedic.net]
Sent: Tuesday, October 12, 1999 5:46 AM
To: towertalk@contesting.com
Subject: [TowerTalk] J-Pole Antenna on HF Bands
Hi TT'ers,
I have a J-Pole design sheet that gives all the formulas for constructing
this Vertical Antenna in the VHF regions.
My Question: Is the J-Pole limited to the higher frequencies, or can it be
also be used in the HF spectrum?
If so, will the formulas work at these lower frequencies?
tnx es 73 de n8csp k
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|