[amsat-bb] Re: Why do the amsats get more and more complex?

[Rick Hambly (W2GPS)]

Les,

> Galileo (if it is ever built and 
> launched and worked) would just be 
> over Europe, right? 

No.

> That would leave the rest of the 
> world the ability to use our L band 
> uplink, right? 

No.

> If we hams are using a dish pointed at 
> the sky with a narrow bandwidth how is 
> that going to interfere with ground 
> receivers some distance from us? 

The high EIRP signals will impinge on aircraft.  Also, other Hams like ATV
will create interference that will not be tolerated for long and all will
suffer the consequences.

> We would be smart enough to not have 
> the Eagle uplink on the same freq, right? 

Wrong, there is almost no place to hide.

> And we would design Eagle such that we 
> could (from ground control) move the Eagle 
> receive freq away from any potential conflict 
> with Galileo, right? 

No.

> And Eagle would be in orbit and operational long 
> before Galileo, right? 

No.

> And Galileo receivers on the ground will have 
> the ability to cut out any possible 
> interference from us, right?

No.

> Seems to me that we are planning to give up 
> the L band (as an uplink) 
> based on a lot of bad assumptions.

The assumption that we are giving up on anything, including L-band, for our
satellites (P3E and Eagle) is overblown and untrue.

Rick
W2GPS
AMSAT LM2232
 

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of sco at sco-inc.com
Sent: Wednesday, September 20, 2006 12:16 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Re: Why do the amsats get more and more complex?


Galileo (if it is ever built  and launched and worked) would just be 
over Europe, right? That would leave the rest of the world the 
ability to use our L band uplink, right? If we hams are using a dish 
pointed at the sky with a narrow bandwidth how is that going to 
interfere with ground receivers some distance from us? We would be 
smart enough to not have the Eagle uplink on the same freq, right? 
And we would design Eagle such that we could (from ground control) 
move the Eagle receive freq away from any potential conflict with 
Galileo, right? And Eagle would be in orbit and operational long 
before Galileo, right? And Galileo receivers on the ground will have 
the ability to cut out any possible interference from us, right?

Seems to me that we are planning to give up the L band (as an uplink) 
based on a lot of bad assumptions.

Les W4SCO


>The answer is in two parts. First, an L-band ground antenna would be too
>large to disguise as a TVRO dish. Second, there is fear that over the
>lifetime of Eagle that L-band could become unavailable, particularly in
>Europe, if the Galileo system is deployed.  Galileo would be a primary
>service and Ham transmissions would likely interfere with low cost
>commercial receivers.
>
>I don't wish to debate these points. I'm just telling you the reasoning
that
>went into not choosing L-band. I assure you that every possibility was
>considered. Lists were created and discussed on each alternative.
>
>Rick
>W2GPS
>AMSAT LM2232



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