[TowerTalk] RE: [50mhz] Re: Fw: Make a 6M halo antenna- K0FF
Robin E. Midgett
rmidgett@bellsouth.net
Wed, 12 Jul 2000 23:09:03 -0500
Hi Pete,
Thanks for your kind offer..I have that same article; I'm looking for the
HO loop specically.
At 02:49 PM 7/10/00 -0400, Peter J. Underhill wrote:
>Dear Robin,
> I have a copy of the ARRL Mobile Handbook (circa somewhere in the
> 1950's
>which has the article on how to make a 6 Meter Halo, which can also be used
>on 2 Meters by switching the ceramic insulator spacing between the end
>plates. I never have built one myself, since I have two 6 Meter "Saturn 6"
>halos which I plan to stack on the tower eventually.
> Send me a SASE (large envelope please) and I'll post a copy back
> to you.
>My address is as follows:
> Pete Underhill N4JAZ
> 4634 Addison Drive
> Charlotte, NC, 28211-3056
> If this message gets back to the reflector, the offer stands for
> anyone.
> Alternatively, I believe the article is also posted on the 6Meter
> Club
>website as a .zip file. So you might try and get it there. I cannot call
>the website address right off hand, but it should be easily found by using
>your search engine.
> Best Regards, Pete Underhill
>
>
>-----Original Message-----
>From: owner-50mhz@6mt.com [mailto:owner-50mhz@6mt.com]On Behalf Of Robin
>E. Midgett
>Sent: Monday, July 10, 2000 12:51 AM
>To: K0FF; towertalk Mail List; vhf@w6yx; 6 Meter Group
>Subject: [50mhz] Re: Fw: Make a 6M halo antenna- K0FF
>
>
>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
>
>
>----
>Visit the Six Club web page at: http://6mt.com/club.htm
>----
>Submissions: 50mhz@6mt.com
>
>to unsubscribe mail to: majordomo@6mt.com
>(In message) unsubscribe 50mhz
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