[time-nuts] Need 10 MHz for DSN space-probe hunting
jimlux at earthlink.net
Tue Sep 13 15:49:10 EDT 2016
On 9/13/16 10:04 AM, Mike Baker wrote:
> Hello, Time-Nutters--
> Full disclosure-- I am a complete newbie at understanding the
> intricacies of generating a really stable, low phase noise, accurate
> frequency reference for microwave reception up around the 8 GHz
> DSN (Deep Space Network) band. I have been following the back
> and forth comments on the Time-Nuts list about improving the
> Trimble T-bolt's 10 MHz output but confess that most of it is pretty
> much deeper technical voo-doo than I am comfortable with.
> I have been following the exploits of a group of folks around the
> world who receive the incredibly weak signals from space probes
> such as Juno. The idea is to detect the signals and then deduce
> and confirm what probe is being detected by analyzing its doppler
> and orbital characteristics.
> Accordingly, what possible options might I have open to obtaining
> a decent 10 MHz frequency reference for working up at the 8 GHz
> DSN band? Any feedback on this will be much appreciated!
I think that any sort of OCXO will do... your tbolt is probably "quiet
It's phase noise in the 1-100 Hz kind of area that you want to think
about, your LO multiply chain will increase the noise floor by
20*log10(N) going from 10 to 8450. (about 60dB)
The carrier you're looking for is very narrow band.. you can look at the
data sheet for a SDST (on General Dynamics website) and get the phase
noise of the AuxOsc, which will be the worst case noise. If they're
doing 2 way turnaround, the noise is better.
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