[VHFcontesting] Stacked Squalos?
extraham at earthlink.net
Wed Oct 4 07:14:51 EDT 2006
Halos, Squalos, and whatever cute name they come up with for these antennas do not have an omnidirectional pattern, no matter what they claim. (Yes, a local ham and I tested them.) In order for a halo to approach the gain of a single dipole in the directions of least radiation, you need to stack at least 4 halos. You really have to consider if you want to go with the complexity of building such an array with a much simpler solution that will outperform such an array.
Two dipoles at a 90 degrees angle will easily outperform a 4 bay h(squ)alo stack. Use either 2 feedlines and a switch at the shack, or switch at the antennas using a relay (reed relays if weight is an issue). Add a simple 555 timer circuit to switch ever 0.5 second or so and supply an override switch and you can sit back and relax. Better yet, use a skeleton slot or dipole groups to do this at much higher gain with similar coverage. I'm sure this isn't too complex of a project for the VT ham club.
Consider which directions are most interesting to you and maybe a simple dipole will suffice. The simple dipole seems to have lost its allure, but bend the thing to have it radiate in a peanut shape pattern, mutilating its gain figure, give it a cute name and it sells like hot cakes. :-)
Yes, I built halos and 2 and 4 bay stacks, but after many conversations, experiments and shared experience, I'm convinced that switching is the way to go (for stationary use).
>From: "Joshua M. Arritt" <jarritt at vt.edu>
>Sent: Oct 3, 2006 5:56 PM
>To: vhfcontesting at contesting.com
>Subject: [VHFcontesting] Stacked Squalos?
>A couple folks in the Virginia Tech ham club are considering adding
>omni-directional receive antennas for 6, 2, and possibly 432 (and 222,
>once I get my xverter running) to augment the modest yagi farm used in
>VHF/UHF contest. I agree that having something omni to switch to during
>search-n-pounce periods could be advantageous on bands where we're using
>boomers now. I've built a few 2 meter squalos for singleton mobile use
>in the past and they've worked OK... but I would think stacking bays of
>these would be in order for a little more gain in a contest. It seems
>I've seen posts where folks have mentioned such arrays before on this
>Any suggestions/war stories/words of wisdom for constructing and using
>such a beast? Is the stacking theory a little overboard? How many bays
>do the big guns run? Is it worth building them for 432 and above (sans
>the dish and horn bands)? End-fed vs. center-fed? How about noise
>considerations? Anyone doing half-wave spacing for the lower angle --
> Thanks, and CU in the 432 sprint!
> - Josh, KF4YLM
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