[amsat-bb] Re: [amsat-edu] Link Budget for Cornell University's student built satellite Violet

[Yoon Ho Lee]

Our satellite is actually a nanosat, with 50cm by 50cm by 60cm (W x L x 
H), so we do have enough space to use two patch antennas.
Would you like to explain more about the receiver noise temperature ? 
I'm having a hard time estimating how much effect the noise temperature 
has on a link.
Thank you.

-Danny

Nick wrote:
> Hi Danny
> You did a good job on the link budget. Jan King is the author and he will
> comment if you send him a copy. Here are my comments.
>
>
> 	1. Patch antennas are hard to put on a cubesat because of their
> size.
> 	2. If you fly dipoles they have very deep lobes of the end of the
> ends and will cause deep
>          fades when the antenna alimented off the ends.
> 	3. The ground antenna when at 5 degrees  elevation look into the
> warm earth i.e. 290 deg K
>
> For a reality check go copy AO 51. Copy the telemetry beacon. It uses FSK
> modulation and if you chose GMSK it is several db improvement over FSK. The
> antenna are turnstile with 2 db gain circular polarized. AO-51 keeps the
> antennas nadir pointing so there is very little fading due to polarization
> misalignments and this is a challenge on 10 cm cube.
>
> If you make it to the cube sat conference at San Louis Obispo look me up I
> am 6 ft tall with red hair and 64 years old.
>
> Good luck
> nick
>
> -----Original Message-----
> From: Yoon Ho Lee [mailto:yl482 at cornell.edu] 
> Sent: Wednesday, April 15, 2009 9:18 AM
> To: Nick
> Subject: Re: [amsat-edu] Link Budget for Cornell University's student built
> satellite Violet
>
> Hello Nick,
>
> It seems like the listserv denied my attachment. Here are the files.
> Thank you for your interest and help!
>
> -Danny
>
> Nick wrote:
>   
>> Hi Danny
>> I will review your link budget but it was not attached to your email.
>>
>> Please reply directly to this email off list
>>
>> nick
>>
>> -----Original Message-----
>> From: amsat-edu-bounces at amsat.org [mailto:amsat-edu-bounces at amsat.org] 
>> On Behalf Of Yoon Ho Lee
>> Sent: Tuesday, April 14, 2009 7:12 PM
>> To: amsat-edu at amsat.org
>> Subject: [amsat-edu] Link Budget for Cornell University's student 
>> built satellite Violet
>>
>> Dear whom it may concern,
>>
>> I'm Danny Lee from Cornell University's student built satellite team 
>> Violet, working on Electrical Subsystem, specifically Telemetry and
>>     
> Control.
>   
>> For those of you familiar with CUSat, our team is under the same UNP 
>> program, on the 6th competition.
>>
>> I have worked out a preliminary link budget from limited resources and 
>> knowledge, and I would greatly appreciate any input from experts out
>>     
> there.
>   
>> Please read the note before proceeding to the spreadsheet.
>>
>> Thank you very much in advance, and I look forward to your input.
>>
>> Sincerely,
>>
>> Danny Lee
>> Electrical Subsystem,
>> Team Violet,
>> Cornell University
>>
>>
>>
>>   
>>     
>
>
>
>
>