[TowerTalk] Re: Fw: Make a 6M halo antenna- K0FF

[Robin E. Midgett]

Do any of you have a copy of the ARRL Handbook which shows construction 
details of the HO loop? I understand that design was documented by the 
League many moons ago...I'd love to get a copy of the article if any of you 
would be willing to share it. I'll cover costs & post the info if people 
are interested in brewing their own HO loop.



At 10:35 AM 7/8/00 -0500, K0FF wrote:
>Repost due to multiple requests. Geo
>-----Original Message-----
>From: K0FF <K0FF@ARRL.NET>
>To: Tower Talk (mail list) <towertalk@contesting.com>; VHF reflector
><vhf@w6yx.stanford.edu>
>Date: Tuesday, May 23, 2000 11:38 AM
>Subject: Make a 6M halo antenna- K0FF
>
>
> >Here is the parts list and dim. sheet for a 6m Squalo, made from copper
> >water pipe. It is more or less omni-directional, and horizontally
>polarized.
> >It presents a high angle of takeoff when mounted low, and singly (great for
> >Es), and can handle 100W.
> >It's just a dipole folded around on itself, and supported at the far end
> >with a plastic insulator.
> >The shape is a closed 28" square, with a mounting bar through the middle.
> >This mounting bar is attached to a copper TEE at the drive end, and to a
> >PVC TEE at the other end. The PVC TEE acts as support and end-insulator for
> >the radiating element. A large (3/4") part is used, and adapted down to fit
> >the water pipe, to increase it's insulating qualities, as there is very
>high
> >voltage at this point. A strip of brass or copper 1/2 by 3" is screwed to
> >the outside middle portion of the PVC Tee, through a small center hole, and
> >is rotated one way or the other as a resonance tuner(butterfly). A gamma
> >match sets the impedance to 50 Ohms, and the butterfly adjusts the center
> >frequency.
> >A U bolt and saddle through the central tube provides a center mounting
> >point. Another approach is to install a copper TEE in the center tube, with
> >the open end down. In that open end solder a 1/2" brass rod which has been
> >drilled and tapped for 3/8-24.
> >Side mounting on a tower can be achieved by using conduit clips to fix it
>to
> >a horizontal mast.
> >
> >Material:
> >1/2" Cu waterpipe :
> >3 ea. 27 inch piece
> >4 ea. 12.5 inch piece
> >
> >3/8 i.d. Cu refrigeration tubing :
> >1 ea. 13.5 inch piece (p/o gamma)
> >
> >Brass plate: 1"x 2-1/2 in (to mount so-239, gamma rod)
> >
> >4 Cu 90 Degree elbow
> >1 3/4 PVC TEE
> >1 3/4 to 1/2 PVC reducer
> >1 Cu TEE
> >
> >Glue two of the 12.5" pipe sections into the PVC reducers first, then glue
> >the reducers into the opposite sides of the PVC TEE.
> >Lay the assembly on a flat surface with the center opening of the TEE
> >facing the middle of the antenna. This is where the first 27" piece
> >(mounting
> >bar) goes in, via a reducer. On the outside edge of the PVC TEE is where
>the
> >
> >butterfly attaches. For mobile or portable use, use 3 s.s. #6 screws
>through
> >each of the PVC TEE joints for added strength.
> >The rest of the antenna solders together to form a square, using the 90
> >degree elbows at the corners.
> >The brass plate is bent to form an "L" 1-3/4"  tall with a 1/2" lip. A 5/8
> >hole is provided 1-1/4 inch from the bend, and an so-239 is attached . Two
> >small holes are drilled in the lip and the plate is mounted to the copper
> >TEE with #6 s.s. self taping screws. Solder the center conductor of a 11"
> >piece of RG8 insides (center wire and plastic dielectric only- remove and
> >discard shield and outer covering). Slip the RG8 insides into the 3/8"
> >copper tube 10.5", and tap the copper tube to the radiating element 13-1/2"
> >from
> >the so-239 center, with a copper strap.
> >
> >The tap on the Gamma sets the impedance presented to the feedline.
> >Resonance (center frequency) is adjusted by turning the butterfly.
> >
> >
> >Mount 15 feet or more high, for home use, and wherever you can for mobile.
> >An antenna like this can be mounted 3" to 6" above the roof of a vehicle
> >using PVC or acrylic spacers with suction cups.
> >
> >
> >Have fun on 6. K0FF
> >
> >
> >
>
>------
>Submissions:                    vhf@w6yx.stanford.edu
>Subscription/removal requests:  vhf-request@w6yx.stanford.edu
>Human list administrator:       vhf-approval@w6yx.stanford.edu

73,
Robin E. Midgett KB4IDC EM66se
rmidgett@bellsouth.net
1/2 of the Award Winning NT4L Rover Team
http://www.almostanywhere.com/vhf/vhf.html


--
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com