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

Re: Oscar-Zero anyone?




Hello Edward!

25 Dec 00 11:00, you wrote to All:

 >> Firstly, the free space losses are sqr(400000/40000), or 100
 >> (roughly, i.e. 20dB.
 EC>
 EC> **0oops:  did the miles vs km error.  Also, did anyone catch the
 EC> perigee vs apogee goof!  Maybe NASA will hire me back to help design
 EC> Mars missions...groan ;-)  {now where did I put that sliderule?}


Hehehehe :)

 EC> **That may be.  Ten degrees is ~20 dBi gain.  And I would think this
 EC> would suggest microwave freqs. so the ground station antenna gain is
 EC> easier to achieve.  In 20 years this may not be this hard.

Yes, microwaves would probably be the way to go.  But for that sort of
distance, it would be nice if we could go beyond the 20dBi point (I think
someone's done a link budget somewhere).

 >> Tracking is the other option, which would lower the long term
 >> reliability of the system.
 EC>
 EC> **Why tracking?  Other than libration, the moon rotates once/per orbit
 EC> around earth.  In other words, the same point on the lunar surface
 EC> faces earth throughout the lunar month.  {approximately}

Point was if you wanted > than around 20 dBi gain, you would have to track the
Earth, or you'll lose the signal perodically due to libration taking the Earth
out of the beam.

 EC> Of course the ground stations will need to track...so what?  This
 EC> isn't a "everybody gets to do it with an HT" project.

Goes without saying :)

 EC> **Oh I figure we would just plug into Luna-Edison ;-)
 EC> Seriously-->Probably not practical on a autonymous mission; only
 EC> piggyback with some NASA mission like a MoonBase. {which probably
 EC> would have solar/nuclear isotopic thermal-electric generation system}

Yes, a permanent manned presence on the Moon would improve the feasibility
considerably.

 >> Would be rather expensive, to get it up there.
 EC>
 EC> **Yep!  Morgage everything..its worth it ;-)

LOL

 EC> **OK, HOPE THIS WAS FUN...WE CAN DROP THIS ONE AND MOVE ON TO SERIOUS
 EC> STUFF! "now about that repeater on Mars..."

Hehehe, hang on, I know of a spare 3000' dish left over from an alien probe,
perhaps we could coax it into orbit around mars <tongue planted firmly in cheek

;) >

Tony, VK3JED

.. pool, can I swim without getting wet?
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home