[eagle] Re: Eagle 10 MHz Clock

Jim Sanford wb4gcs at amsat.org
Mon Apr 9 20:06:20 PDT 2007

Bill et al:
The requirement for the 10MHz reference descends from the July 2004 
meeting in Orlando.  As far as I know, it was never thoroughly 
justified, it was stated and made sense at the time.  Still does, to me, 
tho I could be convinced on a case basis that we might not need it.

wb4gcs at amsat.org

Bill Ress wrote:

>Some very good dialog has been taking place, lead by Juan Rivera as he 
>heads up the prototype U Receiver build and test project.
>Several very important questions have been raised but I'd like to 
>address just one with this post.
>I've volunteered to design and build the S2 Receiver and the C 
>Transmitter and support microwave component efforts on the phased array 
>for each. I am finishing efforts on a "prototype" single channel 
>(assuming there might be several) S2 downconverter.
>I fully recognize than "many" system design parameters have not yet been 
>defined but I'm trying to get that "definition" effort moving along.
>This is the first one I'd like to address.
>In the coarse of designing the LO for the "prototype" S2 downconverter I 
>have not been too concerned with use of the 10 MHz satellite clock. But 
>I think it's time for "system" project guidelines to be developed for 
>this issue since it can affect the design of all LO's. I have looked for 
>guidance on the subject in Eaglepedia and have come up short. Point me 
>in the right direction if it's there (and I just couldn't find it).
>I hope I'm not rehashing old discussions (I've only been on the team 
>since last October) but here are my questions:
>1) What is the reason for requiring all LO's to be locked to a 10 MHz 
>satellite system clock or are they?
>2) Have the performance specifications for the 10 MHz clock been 
>developed and what are they (in particular phase noise, frequency 
>stability, susceptibility to digital hash, and power level available to 
>each using subsystem - to name a few)?
>My apologies for sending to the entire Eagle list but I'm not sure who 
>has the responsibility for the clock.
>Probably more questions to follow!!!
>Regards...Bill - N6GHz
>Via the Eagle mailing list courtesy of AMSAT-NA
>Eagle at amsat.org

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