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Re: [linrad] More Mars info and questions


extra bits and bandwidth will do no harm, they will just waste computer
resorces. If you hve the extra CPU power and disk space, you will
loose nothing by oversampling.

As for the bin width, I think I remember reading on Mars-net that the
oscillator onboard MGS is probably not stable enough for less than
1Hz bins.

What I am afraid most is that the LO in typical amateur transceivers
has too broad a spectral line (phase noise, "hairy" PLL's etc).

For frequency reference I don't have the option to lock the receiver,
but will try to inject a reference tone. I use an GPS locked 10MHz
standard feeding clock to an AnalogDevices 9850 DDS demoboard,
which has useful aliases all the way up in the GHz range.

As for the specific LINRAD questions, I cant really help, since I'm not
yet a real LINRAD user. I plan to write my own small piece of
software just for the MGS, since I don't think the nonlinear doppler
can be removed by LINRAD?

However, I'm not sure if I'll be able to do the recording, yesterday
I was at S51ZO and we found he has a sensitivity problem in his
70cm system, when we checked the celestial sources.

73, Marko

On Saturday 23 August 2003 16:00, w3sz wrote:
> 1.  It is a problem to sample at 16 bits rather than 8 if the CPU handles
> it?  I thought this would always be an advantage, or at least no
> disadvantage.
> 2.  If the bins can be kept equal to or smaller than whatever the ideal
> width is, then is
> there a disadvantage to making the waterfall wider, as I want to do,
> assuming there is no aliasing at the desired signal?  Again I am assuming
> that the CPU can handle the work.