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Re: AO-7


Thanks for the info and comments on AO-7.  I suspect there will be some
migration to AO-7 from AO-40 and operators need to be aware of limitations.
 The recent questions about FM or AM are particularly pointed.  Any mode
that is RF "hungry" is problematic.  I have not run CW on the sats much so
not aware that operation is common at slower speeds.  On EME the norm is
15-20 wpm.  I am not any great shakes on cw but it comes into use for modes
like eme, ms, Auroral-Es, and terrestrial mw (all weak signal, QRP-like

I was not aware that it took so little ERP for AO-7 (I assume this is
mode-B).  I will have to try it ;-)

73s, Ed - AL7EB

At 11:33 PM 2/3/2004 -0800, Emily Clarke wrote:
>Hi James,
>It was the end of a long day where I got about 20 email comments similar to 
>yours, so I apologize - I should have also put the smiley on my comment as 
>well but was running out to a meeting at OES.  I'm also the NEST 
>(Neighborhood Emergency Services Team) captain here in my neck of the woods.
>The problem with Oscar 7 and CW isn't as much that fewer hams know it 
>(which is true) but that the operators are slower (ie, the dahs and dits 
>are longer) and there is less power to go around.  The result is that CW 
>takes more power out of the satellite than it probably did when operators 
>were sending 20 WPM.  Because of the voltage drops people send 5-10wpm and 
>the longer key down state is really draining power.  People are talking 
>about PSK (100% duty cycle) and full down RTTY (also 100% duty cycle) on 
>AO-7 and don't realize that this could kill it.  Warble city.
>I usually run about 25W ERP on AO-7 and usually have to turn that down to 
>about 6W ERP (lowest I can go) when it gets close.  I know of some CW ops 
>who are doing CW and when they key up you can hear the dits and dahs over 
>the entire pass band.  But no one can cite them for it because it's not 
>them, it's AO-7.  So what's a mother to do? (so to speak) The only thing I 
>can think of is to try to point things more toward SSB voice and hope that 
>is what people concentrate on.
>I'd hate for AO-7 to break - crushed would be more like it.  I think it's 
>Pheonix existance will inspire and encourage people for a long time.  It's 
>already giving AO-40 operators and control operators hope.  So I hope you 
>will join me in trying to encourage people to work AO-7 safely, with the 
>knowledge they are using something that in any other era would probably be 
>considered a museum piece.  I hope people will try to preserve this 
>wonderful satellite resource for generations to come.
>At 08:01 PM 2/3/2004 -0700, you wrote:
>>Sorry Emily - I meant it as a joke. Sorry I didn't attach the smiley face.
>>CW is a good cheap way to get on the analog satellites; one can key the PTT
>>of an FM rig to get on. Lots of people got introduced to the satyellites via
>>Mode A this way.
>>Of course fewer hams know CW for this tour of Oscar 7 than the last one.
>>Again, this wasn't meant to be a slam on you, just a joke. Please forgive.
>>Back in my hole. - Duffey
>>James R. Duffey KK6MC/5
>>Cedar Crest NM 87008 DM65
>W0EEC - CM87tm
>AMSAT Area Coordinator - San Francisco Bay Area
>http://www.projectoscar.net    http://www.PlanetEmily.com 
>Help Launch Echo - http://www.amsat.org/amsat/sats/echo/index.html
>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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