[time-nuts] funky frequency

[Predrag Dukic]

Isn't EROS name of one of the asteroids?  There was also some mission to it

some time ago....

part# EROS-750-MA111   might have something with it.  :))







At 02:43 20.11.2009, you wrote:
>More likely it multiplies up to something useful.
>
>For instance, for deep space communications, older radios multiplied up
>something around 5 MHz to get the 2.x GHz or 8.X GHz transmit frequencies..
>9.5625 MHz * 880 gives 8415 MHz, which is in the middle of the Deep Space
>"space to earth" band.  The corresponding earth to space frequency would be
>749/880 times that.  Similarly in the 2 GHz band, the ratio is 221/240.
>
>The entire system is based on the crystal frequency chosen for your channel
>and stuff is divided up and down.  Until very recently, you got an
>allocation for your mission (many years in advance) and you'd order your
>crystals, wait a couple years for them to be delivered, then install them in
>your radio and tune it up.  If your mission happened to use a spare radio
>from a previous mission, you'd hope you could use the same channel so you
>didn't have to get a new crystal.
>
>
>More at
>deepspace.jpl.nasa.gov/dsndocs/810-005/201/201A.pdf
>
>
>Not that your OCXO was used for that, but there are a remarkable number of
>fixed frequency systems around with oddball frequencies.  I'll bet there's a
>lot of terrestrial microwave systems that multiplied a ovenized oscillator
>up to the frequency of use, and since they're on fixed allocated channels,
>there's no particular reason why one frequency is any better than another...
>They're all custom.
>
>
>On 11/19/09 10:48 AM, "Don Latham" <djl at montana.com> wrote:
>
> > I just found in my dusty junk, a couple of ovenized frequency sources at
> > 5.199155 MHz, part# EROS-750-MA111 Dunno why I got these. Is this a magic
> > frequency? It does not seem to divide down to a baudrate...
> > Don
> >
>
>
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