[amsat-bb] Re: Frequency advice requested MM

MM ka1rrw at yahoo.com
Mon Apr 13 04:13:09 PDT 2009



Hi Graham:

F.Y.I., 
WIMAX is using the 5ghz band in Europe.  Most antennas are outside and running low power less than 4 watts erp.  Wimax systems are usually installed in Dense cites or densely populated residential areas.

I installed a 5 Ghz system in Marousi (Athens Greece) a few years ago.  From 1 tower I was able to provide 2-mbit speeds at a distance of 10 kilometers and cover the whole city with just 1 tower.

I used 6 (60-degree) antennas to get a full 360 pattern.  I also placed each antenna on a different channel (I used the whole band). The antennas installed at the houses were similar, running less than 1-watt erp.
I was also able to get a Wimax LOS detectable signal to the Island of Agena (45 km) from my Marousi tower, if I had another dish, I could have had a useable signal all the way to the island.

Since these antennas are aimed horizontally and trees suck up 5 Ghz, their useful range is usually limited 5-10 km from each tower. Anyone living near one of these towers (usually in a city) will have issues with listening to satellites.
A good directional satellite dish will block most of the offending signals.


Wimax frequencies 5.725-5.850 Ghz bands


Take care, Miles WF1F

,

--- On Sun, 4/12/09, Graham Shirville <g.shirville at btinternet.com> wrote:

> From: Graham Shirville <g.shirville at btinternet.com>
> Subject: [amsat-bb]  Frequency advice requested
> To: amsat-bb at amsat.org
> Date: Sunday, April 12, 2009, 7:54 AM
> Hi all,
> 
> AMSAT-UK is involved with the development of a "C
> Band" beacon to be deployed on a satellite in low earth
> orbit sometime during 2012. The satellite is ESEO - The
> European Student Earth Orbiter and the beacon will be part
> of an amateur package which will also include U/S and U/V
> linear transponders. 
> 
> The beacon has to be somewhere in the 5830-5850MHz part of
> the band as this is the allocation that is available for
> space to earth transmissions. So the question is - what
> would be the best part of the band to use - taking into
> account existing ground equipment and antennas (if any) and
> potential QRM from other terrestrial systems.
> 
> Any ideas or suggestions will be most welcome!
> 
> thanks
> 
> Graham
> G3VZV
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