[NLRS] 10 GHz antenna needed

[Arliss]

Thanks for the information, Jerry.

73, Arliss W7XU

On 7/29/2015 9:23 PM, Dr. Gerald N. Johnson wrote:
>
>
> I believe W6DFW is a silent key now. That was mentioned in the
> SBMS newsletter several months ago.
>
> There is a Danish source, probably not cheap.
> www.procom.dk/products/microwave-antennas/10-ghz/omnidirectional-antennas/wgsl-10
>
>
> I have a vertical mill, but too many projects though I'd like to
> put up a 10 GHz beacon too, about half way to the cities. I'm
> considering cutting the slots with a circular saw instead of a
> small endmill to get a much better cut and without breaking small
> end mills from cranking the table too fast in gummy copper. I
> have hundreds of 3 and 4" diameter metal cutting saw blades. But
> I don't know the effects at the ends of the slots being a
> different length at the inside and outside of the guide wall. Or
> having square ends instead of round ends. I suppose I could cut
> most of the slot length with a small saw blade (1" diameter or
> less) and then finish the ends with the end mill to make them
> rounded as most are planned to be with the inside and outside
> lengths the same. Slots could be made by drilling a series of
> holes and connecting them with needle files.
>
> There is a design program at W1GHZ web site that has been proven
> to be good for round ended slots.
>
> There is considerable experience that using standard height wave
> guide results in an antenna with considerable ripple in the
> azimuth pattern. One solution pushed by Kent Britain is a pair of
> wings to widen the radiating surface. I have also found
> literature that says lowering the guide height is another
> solution. Indeed etching slots in a double sided circuit board
> with a pile of vias to make a dielectric filled waveguide shows
> good circularity. I think it might do OK to just cut the board to
> the guide width and then use copper tape to close it more solidly
> than the gang of vias, though maybe the wider circuit board
> beyond the guide is acting like Kent's wings on standard copper
> guide. I have a lot more literature to read on that topic.
>
> 73, Jerry, K0CQ