[HamWAN PSDR] Improved radiation pattern software and new antennas on the way

[Bart Kus]

Attached are 2 pix of the ARC and 1 pic of the Laird sectors.  Excuse 
the mess, these were taken before I re-organized and cleaned up the lab.  :)

Excellent point about parasitic reflections.  I had not considered that.

And yeah, I'd love to stick with off-the-shelf.  Really don't wanna get 
into the business of manufacturing antennas.  Wanna build a network!

--Bart


On 2/6/2013 10:33 PM, Rob Salsgiver wrote:
>
> Bart,
>
> Can you send me a photo or two of the internals of one of these sector 
> antennas?  I've done some work with 2.4 but not 5.8. I'm curious to 
> know if they are flat panels or if they are contoured (rounded or 
> otherwise shaped).
>
> I'm thinking along the lines of your sheet metal shields. Depending on 
> the internal design, I'm wondering if we can't apply some different 
> approaches here.
>
> The potential downside of a sheet metal shield is parasitic 
> reflections, unless they are spaced such that they enhance the signal 
> (ala a reflector) as well as shield from adjacent RF.
>
> Using it as a reflector then gets me thinking of applying some other 
> geometries -- how about a yagi or log periodic design for 5.8?  Given 
> the frequencies involved, it likely would fit into a similar footprint.
>
> I need to do some calcs and brainstorming.  There's definitely 
> advantages to having off the shelf equipment, and if possible it would 
> be good to launch with standard items if they work, but there may be 
> longer-term advantages to using some of the benefits of our "amateur" 
> roots if we can get them to be stable and reliable.
>
> Cheers,
>
> Rob
>
> *From:*PSDR [mailto:psdr-bounces at hamwan.org] *On Behalf Of *Bart Kus
> *Sent:* Wednesday, February 06, 2013 9:45 PM
> *To:* psdr at hamwan.org
> *Subject:* [HamWAN PSDR] Improved radiation pattern software and new 
> antennas on the way
>
> Hello,
>
> I've taken some time tonight to improve the radiation pattern 
> measurement software.  The algorithm for auto-centering the rotation 
> of the pattern won't be fooled now by the presence of a non-centered 
> peak lobe.  Full description of the software function and the software 
> itself have both been published to the Antenna Analysis 
> <https://www.hamwan.org/t/tiki-index.php?page=Antenna+Analysis&structure=HamWAN> 
> labs page.  The radiation pattern for the Laid sector 
> <https://www.hamwan.org/t/tiki-index.php?page=Laird+SAH58-120-16-WB&structure=HamWAN> 
> has been updated and you can see the wonky alignment is now gone!
>
> Since neither of these antennas are thrilling performers in the HamWAN 
> Labs tests, a couple more candidates have been added to the Sector 
> Antenna - 120deg 
> <https://www.hamwan.org/t/tiki-index.php?page=Sector+Antenna+-+120deg&structure=HamWAN> 
> component engineering page.  A HamWAN community member who wishes to 
> remain anonymous has generously purchased sample antennas of the 
> Teletronics and RF Elements brands for lab testing.  They should 
> arrive some time next week.
>
> In the meantime, I've had a thought about how to improve F/B ratios in 
> these sector antennas.  Using a sheet of aluminum and my sheet metal 
> brake <http://www.harborfreight.com/30-inch-bending-brake-67240.html>, 
> I should be able to manufacture traditional RF shields, like this:
>
> VARIA 14-19dBi variable sector antenna 45-120°, 2.4-2.5GHz
>
> but without fancy holes or adjustable features.  It might be enough to 
> keep that nasty high power adjacent RF out.
>
> --Bart
>
>
>
> _______________________________________________
> PSDR mailing list
> PSDR at hamwan.org
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