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Re: Current RUDAK freqs?



Ken,
RUDAK is capable of generating signals in many places in the digital 
passband, in fact with the DSP modulators a signal can be generated 
literally anywhere.  However there are two primary downlink frequencies we 
have been using, those are fixed and from two of the hardware modems.

Those frequencies are:
 From RUDAK A: 2401.760
 From RUDAK B: 2401.882

Note that these change somewhat with temperature and of course with Doppler.

We have not had any of the DSP modulators running during this current 
operational period but may crank one up soon.  When we were testing the 
DSPs in the last window we had generated carrier literally throughout the 
digial passband at one time or another.

The third signal you were hearing was probably the result of a mix between 
the two signal above.  If you hear well you can detect mix products in 
various places in the passband.  The more signals we place there the more 
mix products are generated.  The mixes are all around 20 dB below the real 
signals so to hear them you need pretty good equipment.

When we were running the ZRO-like test from one of the DSP mo's last year 
it produced a signal at 2401.860 that lowered output level in 3dB steps 
from max possible down to something like 30 dB below that.  At that level a 
few folks reported they could still detect it.

At the moment we are continuing to test hardware and software and will 
probably continue to do so for the remainder of this operational 
period.  The objective remains to produce usable links for the average 
ground station and open one RUDAK to general use.

Jim
wd0e@amsat.org
jim@coloradosatellite.com


At 09:14 PM 01/24/2003 -0800, Ken Swaggart wrote:
>During the RUDAK operating period on 24 Jan 03, AO-40 Orbit 1027, I copied
>three signals from the satellite. One was a steady carrier, approximately 66
>KHz below the lower frequency RUDAK data signal. The upper and lower RUDAK
>signals were separated by approximately 122 KHz.
>
>So... does anyone have the frequency at the satellite for these three
>signals? I've tried to fit this into the RUDAK A and B freqs, and the three
>signals just do not fit the published spacing. Some months ago I recall some
>postings regarding a steady carrier from RUDAK, but that post is long gone.
>
>Thanks,
>Ken, W7KKE, CN75xa
>
>
>
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