[amsat-bb] Delfi-C3 RASCAL tuning & TLE's

Wouter Jan Ubbels wjubbels at gmail.com
Wed Apr 30 08:08:02 PDT 2008

Hi all,

we have added a section to our RASCAL tuning guide in order to make
achieving sync in RASCAL easier, see


I have also included it in this mail for clarity:

Tuning can sometimes be difficult, in the presence of Doppler shift, fading
due to polarization changes, frequency offset due to temperature of the
spacecraft oscillators and there is the possibility that the Costas Loop
indicates a false sync because of lock on one of the signal's sidebands. If
possible, you can use a waterfall display in software like MixW running
parallel to RASCAL which will give you an indication of the centerfrequency.
During transmission of AX.25 flags, the actual carrier frequency is the
highest peak in the spectrum, with a couple of sidebands exactly 150Hz
apart, looks like a comb. Now, using the waterfall display, tune such that
this highest peak corresponds to 1600Hz +/-100Hz, in order to achieve sync.

Furthermore, Delfi-C3 is now listed on celestrack with identifier DELFI-C3 ,
as object #32787, these TLE's are also on our mission ops page.

Today we also verified that our backup command receiver functions well, we
are still working on the TX drop out issue.

73 on behalf of the Delfi-C3 team,

Wouter Jan Ubbels PE4WJ

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