The analog circuitry also needs to be rad-hard. The object of DSP is to reduce power reqirements and rad-hard solar panels are the million-dollar component.
73,
John KD6OZH
----- Original Message ----- From: "MM" ka1rrw@yahoo.com To: bruninga@usna.edu; "'Joe'" nss@mwt.net; "Jack K." kd1pe.1@gmail.com Cc: amsat-bb@amsat.org; kg4zlb@gmail.com Sent: Thursday, July 02, 2009 15:21 UTC Subject: [amsat-bb] Re: Has anyone considered???
Yes, Digital is an option. However, i would want it to pass through the analog transponder unprocessed. The reason is that we can't afford the Million dollar Radiation hardened chips to support digital processing required on satellites. DSP or SDR will add to the Cost and add many years to the project. WE need projects much faster than have been delivered in the past, 1-2 year schedules not 10 year schedules.
Miles
--- On Thu, 7/2/09, Jack K. kd1pe.1@gmail.com wrote:
From: Jack K. kd1pe.1@gmail.com Subject: Has anyone considered??? To: bruninga@usna.edu, "'Joe'" nss@mwt.net, "'MM'" ka1rrw@yahoo.com Cc: amsat-bb@amsat.org, kg4zlb@gmail.com Date: Thursday, July 2, 2009, 8:40 AM Has anyone considered the notion that the communications from a HEO or Moon or Mars need not be analog? Has anyone considered a digital mode such as WSJT for comms? I know for a fact people are running meteor scatter and EME using a single beam (albeit a long one) and 150 watts. This is not out of the reach of most hams and it is not non-viable communications mode... Heck the US Navy even ran RTTY in the 60's from Hawaii to Maryland as a normal mode of communications (yes it was big and wieldy, I just mentioned it as an aside).
DE - KD1PE - Jack
Why go with the minimal antenna gain? ... any antenna with a 3 db point that exceeds 6.5 degrees is just wasting transmitter power.
I think that would be about a 24 dB gain
antenna. Pretty big
and would take some careful alignment... Kinda
like a realy big
EME array
Just remember what an Oscar 10 station took to have reliable communications, At Apogee it was only 35,000 miles away, the Moon is ...] [250,000 miles]
Which is 7 times farther, squared or 50 times more
power (about
17 dB).
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