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5.x GHz Solid vs. Grid Dish / Equinox vs. Pacific Wireless

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Anonymous
a b F Wireless
July 7, 2004 8:05:18 PM

Archived from groups: alt.internet.wireless (More info?)

Is there any reason to prefer a solid over a grid dish antenna of the
same gain and frequency range? For example, is a 28 dBi solid dish
for ~$500 any better functionally than a 28 dBi grid dish for ~$110?

I notice that some manufacturers (e.g., Equinox, Radiowaves) make dish
antennas advertised as 5.2-5.85 GHz while another (Pacific Wireless)
makes different versions for each of the subranges: 5.15-5.35,
5.47-5.725, and 5.725-5.825 GHz.

What are we to infer from this?

That Equinox, et al is a compromise design, suboptimal on some of the
subranges compared to the uncompromising Pacific Wireless?

Or that Equinox, et al was smarter than Pacific Wireless and was able
to develop a better, more brilliant design that maintains its
performance characteristics across a wider frequency range?
Anonymous
a b F Wireless
July 8, 2004 7:37:36 PM

Archived from groups: alt.internet.wireless (More info?)

Solid or grid first depends on the frequency. Hard to find a grig that
is higher than aroung 3 ghz in frequency. As far as the differences in
design of grids and parabolics there are some huge differences.

The parabolics will generally offer a higher front to back ratio and a
smaller side lobes. The advantages of the solid will be that less
interference is likely to to received. Less interference will
translate into fewer errors and less packet retries.

Even within the parabolic dish range there can be some huge
differences in performance. The more expensive antennas will be
optimized to reduce the side lobes even more than a standard
parabolic.

The last part about specific freqency bands for antennas has to do
with some very critical spacing issues. At 5 ghz a wavelength is
around 2.3 inches and at 5.8 ghz it is 2 inches. These small
differences can make a big difference in how the spacing is between a
feedhorn and the dish. A manufacturer that specifies a certain
frequency being optimal has to manufacture more antennas and keep more
in stock depending on needs. Both antennas would probably work well
across the entire band but usually there will be at least a few dB
difference from one end to the other. By making the dish specific to a
more narrow frequency the best performance can be acheived.


The general rule of thumb is it all comes down to cost. The more you
spend the better the quality and the less problems you will have. If a
link is going to be setup where a 5 9's performance is mandatory then
the extra cost is worth it. If the link is less critical then the
lower cost components may be worthwhile. The use will determine the
quality of components used.



carhore@yahoo.com (c hore) wrote in message

news:<ca167c61.0407071505.1fd538d0@posting.google.com>...
> Is there any reason to prefer a solid over a grid dish antenna of the
> same gain and frequency range? For example, is a 28 dBi solid dish
> for ~$500 any better functionally than a 28 dBi grid dish for ~$110?
>
> I notice that some manufacturers (e.g., Equinox, Radiowaves) make dish
> antennas advertised as 5.2-5.85 GHz while another (Pacific Wireless)
> makes different versions for each of the subranges: 5.15-5.35,
> 5.47-5.725, and 5.725-5.825 GHz.
>
> What are we to infer from this?
>
> That Equinox, et al is a compromise design, suboptimal on some of the
> subranges compared to the uncompromising Pacific Wireless?
>
> Or that Equinox, et al was smarter than Pacific Wireless and was able
> to develop a better, more brilliant design that maintains its
> performance characteristics across a wider frequency range?
July 8, 2004 9:36:55 PM

Archived from groups: alt.internet.wireless (More info?)

carhore@yahoo.com (c hore) wrote in news:ca167c61.0407071505.1fd538d0
@posting.google.com:

Noone replied yet so I'll give it a shot......

> Is there any reason to prefer a solid over a grid dish antenna of the
> same gain and frequency range? For example, is a 28 dBi solid dish
> for ~$500 any better functionally than a 28 dBi grid dish for ~$110?

You can't really answer this question without have the spec sheets for
both in front of you to compare the spec's side-by-side. But, w/o seeing
the sheet's I can say that the grid has a much lower wind load.

>
> I notice that some manufacturers (e.g., Equinox, Radiowaves) make dish
> antennas advertised as 5.2-5.85 GHz while another (Pacific Wireless)
> makes different versions for each of the subranges: 5.15-5.35,
> 5.47-5.725, and 5.725-5.825 GHz.

Those aren't really sub-ranges. Those are different bands. The last one
5.725-5.825 is for the 5.8G ISM (unlicensed, the FCC Chart says it's 5.8
GHz +/-.075 Ghz) band. The first 2 are MOST LIKELY licensed, although I
do know that Motorola sells a 5.3 GHz Canopy product for wireless
backhaul application's, which leads me to believe that there's a small,
little-used unlicensed frequency band in that area, although I could be
completely wrong.

>
> What are we to infer from this?
>
> That Equinox, et al is a compromise design, suboptimal on some of the
> subranges compared to the uncompromising Pacific Wireless?

You might say that, or more likely, the difference in the 5.2-5.825 and
the Pac Wireless ones is that the other companies chose to design, build
and stock one antenna, whereas Pac decided to design, build, and stock 3
different antenna's.

>
> Or that Equinox, et al was smarter than Pacific Wireless and was able
> to develop a better, more brilliant design that maintains its
> performance characteristics across a wider frequency range?
>

Again, you can't really say anything about any of the design's w/o
haveing the specs in front of you.
Anonymous
a b F Wireless
July 9, 2004 3:08:26 AM

Archived from groups: alt.internet.wireless (More info?)

On 7 Jul 2004 16:05:18 -0700, in alt.internet.wireless , carhore@yahoo.com
(c hore) wrote:

>Is there any reason to prefer a solid over a grid dish antenna of the
>same gain and frequency range? For example, is a 28 dBi solid dish
>for ~$500 any better functionally than a 28 dBi grid dish for ~$110?

Well, probably its a bit better. Provided the holes are small enough,
they're irrelevant tho.

>That Equinox, et al is a compromise design, suboptimal on some of the
>subranges compared to the uncompromising Pacific Wireless?

Yes, most likely. The radio has to be focussed on the reciever, adn the
focal point varies with frequency. Thus a broad-spectrum antenna must be
compromising on the best point.

>Or that Equinox, et al was smarter than Pacific Wireless and was able
>to develop a better, more brilliant design that maintains its
>performance characteristics across a wider frequency range?

This is sort-of possible. Its a bit like a Newtonian telescope vs a cat of
some sort.

--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html&gt;
CLC readme: <http://www.angelfire.com/ms3/bchambless0/welcome_to_clc...;


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