Stuart,
I think I can say this without offending you, but this must be the most
complicated thing ever invented, or else my brain is finally starting to
show signs of carelessness in my younger years. Forgive me for not
understanding anything in the explanation below, even after reading it about
five times.
Let's start with the basics. The antenna shown in the photographs is
constructed for what frequency?
Regards,
Al W6LX
> -----Original Message-----
> From: Stuart Rohre [mailto:rohre@arlut.utexas.edu]
> Sent: Tuesday, 16 April 2002 3:56 PM
> To: qrp-l@Lehigh.EDU; AQRP@yahoogroups.com; k5gp@texas.net;
> tentec@contesting.com
> Subject: [TenTec] cone Antenna PHOTO of how to wind them
>
>
> Hi Folks,
> Thanks to Steve Weber for his prototype photo of the folded
> conical helical
> antenna on the link below:
>
> This is with the one monopole mounted, and ready for more to
> be wound. I
> really appreciate his doing this intermediate version, as the
> four monopole
> version gets the turns so close together, a picture does not
> show clearly
> what is going on. It is not too clear with the insulation on
> the wires and
> same color; but the wire toward the slant edge is the no. 10
> here, and the
> wire toward the central axis in each turn, is the no. 12. At
> the bottom,
> the no. 10 goes to coax shield, the no. 12 to coax center lead.
>
> A few notes about this pair of pictures. The Cone will not
> normally be used
> in this configuration, it MUST be over a radial plane or
> ground plane screen
> at least 6 feet square to work properly. The wide end of
> cone must be up
> and small end closer to ground.
>
> The Monopoles must start witht the short, (fold) at the wide
> end. This wide
> end is 16 inches diameter for either 10m model or a 20m
> model. The vertical
> axis where the coil supports join should be 13 inches high.
> The slant length of the supports over which you drill holes
> should be 12
> inches long first turn to last.
>
> The end of the monopole at the narrow part of cone must go to
> coax without a
> balun, and the coax connections must go straight off the
> narrow end of cone
> and through the ground screen before making a right angle
> turn as shown
> here.
>
> Remember the wide end is parallel to ground, and ground
> plane. Notice the
> holes predrilled in between turns for the second monopole to
> be threaded.
> In a similar manner, for optimum performance and match to 50 ohms, you
> should have one turn pair of the first monopole, then allow 3
> pairs of holes
> for the other monopoles. Thus, when all are threaded, you have a pair
> terminated at the top of the cone wide part, and then wind
> the next pair
> starting 90 degrees from the first start, and so on, so each
> succeeding pair
> is below the pair above, pair 1, 2, 3, 4. Since they start
> 90 degrees
> apart around the wide part, they should end 90 degrees apart
> around the
> narrow end, but you are going to solder all the no. 12's to
> coax center
> lead, and solder all no. 10's to coax shield and ground screen, (or
> radials).
>
> Now that you have a picture, if you have any questions, please write:
> <k5kvh@arrl.net>
>
http://www.qsl.net/kd1jv/cone.HTM
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