[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: This Weekend in Minneapolis: Central States VHF Society Meeting



Bruce, Kevin and all:
I respond with JIM SANFORD'S OPINION, which is formed by the perspective 
of having attended the meeting as the Eagle project manager.  Still, 
it's my opinion -- not official position of the Eagle project..


>>Another thing bothers me frankly.  I read BOD candidates response to
>>the
>>question of whether or not they are active on current satellites and
>>almost
>>to a man they give very understandable reasons why they are not active
>>on
>>existing satellites.  (Tom I forget how or whether you answered this
>>particular question so forgive me if I lump you in this next statement
>>mistakenly.) Yet some of these same candidates are designing Eagle to
>>operate on bands that until now where never used by the satellite
>>service.
>>I certainly hope you BODs and rocket scientists put your money where
>>your
>>mouth is and invest in the radio equipment necessary to communicate
>>through
>>Eagle along with the rest of us and get on the thing at least once in a
>>while.  If you lead the way in actually operating in these new bands
>>when
>>Eagle is flying then maybe I and others will consider doing the same.
>>
>>    
>>
>
>As I understand it, they are asking you, me and all other hams to invest in
>this equipment because they believe that in a few years' time S band will
>be unusable for a downlink. In which case, our investment is already lost
>for the purpose of Eagle and we should be grateful for the analysis that
>made us aware of the fact.
>
Yep, we believe that S-band is/will be unusable for weak signal 
downlink.  (The meeting report on EaglePedia shows how many watts/amps 
must be generated.)  More important, this conclusion is driven by some 
measured data which has not yet been well published.  If you have an 
802.11b/g card, do some war driving or other spectrum search, and see 
how many of your neighbors' networks you see.  I know some folks who 
have been able to succeed despite this, I know others who can no longer 
hear anything on S-band due to the raised noise floor.  It will only get 
worse.  I'd LOVE to be proven wrong -- I have a LOT of S-band equipment 
that I'd like to use when I reestablish my satellite presence after 
moving from VA to PA.  Why haven't I done that sooner?  The current crop 
of LEO's is of little interest to me -- been there, done that, don't 
care about the T-shirt, so I'm putting my energy and resources in 
getting an HEO that DOES interest me in service.  At the appropriate 
time, I will put my resources in to reestablishing my satellite 
capabilities -- long before P3E or Eagle fly.

> If the analysis is incorrect, I imagine the
>designers would be happy to be proven wrong, given how much more experience
>there is with S band in the satellite design community.
>
YES!  Please prove us wrong -- but bring DATA.

We are aware of the cost issue and consider the need to design an 
affordable digital ground station along with the space segment to be an 
important REQUIREMENT.

>In either case, we will be able to use S band equipment in HEO on P3E and
>SSETI ESEO, and I assume the dish and pointing equipment for 23cm could be
>reused for 9cm. 
>
>As to the question of the designers buying the equipment required, I
>understand the plan with C-C rider and its replacement is for ground
>stations to be developed in tandem with the bird. The designers will be all
>the more on board if that's the case. 
>
YES!!!!!

>If it's simply a question of who's
>spending money to get this thing going, I have to say I believe the
>designers are likely spending a few dimes more than you or I. 
>
>  
>
Maybe not yet, but soon -- SOMEBODY's got to test the thing!


Thank you all.  I view this as a reasonable set of questions and a 
healthy discussion.

Please pay close attention to the AMSAT Journal, ANS, and EaglePedia.  
Our design and analysis process is open.

The culture of the Eagle team is to make DATA DRIVEN decisions based on 
SOUND PEER-REVIEWED SCIENCE.  As  you watch us work, if you think we're 
wrong or missing something, please provide me the DATA or SCIENCE.  I 
guarantee you that we'll consider it.

Thanks & very 73,
Jim
wb4gcs@amsat.org

James A. Sanford, PE
AMSAT Eagle Project Manager
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home