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

Fri Feb 8 10:12:23 PST 2013

I was thinking of the Ubiquiti system as a whole.

Steve

On Feb 8, 2013, at 9:59 AM, Bart Kus <me at bartk.us> wrote:

> I'd like to identify a set of HamWAN-approved antennas we can use.  Ones which meet HamWAN's requirements and pass testing.  Any antenna which performs up to the requirements can be accepted.  So far, I have not found 1.  So we've got a few more candidates on the way.  The Laird is not quite out of the running yet, it needs to be outdoor-tested to measure the true backside performance.  The Laird is, however, incredibly expensive @ $180/ea.  And it has poor frequency response at the high end.  Unlikely to be selected.
>
> For the time being 5GHz is it.  There's plenty of spectrum to grow in there, and when that's all exhausted we can expand to other bands like 3GHz or 10GHz.  But I expect 5GHz is here for quite a while, a few years at least.
>
> Now, you mentioned Ubiquiti, so if your question was about modems, I'll have to reply in more detail.  :)
>
> --Bart
>
>
> On 2/8/2013 8:08 AM, steve monsey wrote:
>> Just curious, seems like you just want to settle on one manufacture ?
>> Like Ubiquiti?
>>
>> Are you just using 5 ghz or 3 ghz as well?
>>
>> I agree that not making a line of equipment is the best idea for
>> something that will last and replaceable. Sometimes you have to do
>> one-off's for a special installation. Plus you can maybe get a price
>> break for buying in bulk for the first go around.
>>
>> Steve N0FPF
>>
>>
>>
>> On Feb 7, 2013, at 10:21 PM, Bart Kus <me at bartk.us> wrote:
>>
>>> 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
>>>>
>>>>
>>>>
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>>> <mime-attachment>
>>> <LairdSector1.jpg>
>>> <ARCSector2.jpg>
>>> <ARCSector1.jpg>
>>> <mime-attachment>
>
>
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