[amsat-bb] Re: P3E/P5A S -> X transponder

i8cvs domenico.i8cvs at tin.it
Sat May 29 12:43:43 PDT 2010

----- Original Message ----- 
From: "Michael Fletcher" <oh2aue at kolumbus.fi>
To: <amsat-bb at amsat.org>
Sent: Saturday, May 29, 2010 3:55 PM
Subject: [amsat-bb] P3E/P5A S -> X transponder

> Hi all ye Microwavers,
> AMSAT-OH is working on the S/X band coherent/linear
> transponder for P3E. The Coherent mode is a fully
> functional testbed for the P5A ranging transponder.
> Especially the linear transponder prototype has been
> assembled and verified with over-the-air tests and
> laboratory tests. Flight versions of the submodules
> have been and are being produced at this time with
> our eyes now set on integrating these together and
> cabling the whole job together.
> Full verification of the Coherent Mode requires a
> fully functional command station AND a functional
> IHU + CAN environment to interface our data ports with.
> No such tests have been available yet, but all our
> preliminary testing and evaluation of the Coherent
> Processor have shown proper operation of the design
> and circuitry (e.g. locking onto a "modulated" uplink
> carrier, tracking this etc.). So far correct live
> operation of the Coherent Mode is our biggest questionmark.
> Our national team meets on a regular basis every 4 - 6 weeks
> for testing and followups of the work of each individual.
> This transponder is especially complex as you can
> see from these key figures:
>      * 9 different local oscillators
>      * All local oscillators locked to the common 10 MHz USO
>      * 21 different frequency mixers
>      * 13 different intermediate frequencies
>      * Linear Mode output power on 10 GHz: 3 W PEP
>      * P5A Mode output power on 10 GHz:  1 mW PEP
>      * 38 control lines on the CAN interfaces
>      * 2 CAN interfaces, one in multiplexed mode
>      * 4 dedicated direct control lines interfacing with the IHU
>      * 14 analogue telemetry lines to the CAN bus
>      * Coherent Mode Uplink/Downlink ratio is fixed at 30:7
> Here you may find a general outline webpage, though unfortunately in
> Finnish for the benefit of our OH supporters, but you might still enjoy
> the photos and drawings:
> http://www.rats.fi/rats/amsat-oh/
> Our team sincerely hopes funding will eventually be found
> for P3E/P5A - this is the only thing that keeps us motivated
> to continue our work. On the other hand we are clearly behind
> schedule, so the delays are welcome :-) But then again, any
> news of progress would boost our production rate phenomenally ;-)
> 73 Michael, OH2AUE
> -- 
> "Life is too short for Sudoku"

Hi Michael, OH2AUE

I am very happy to see that AMSAT-OH is working on the S/X band
coherent/linear transponder for P3E/P5A 

Don't forget what you promises on 11 may 2008 about the frequency
band for the Downlink  Linear  10451.000 MHz  ~2 MHz because
many of us are already equipped with X band downconverters and dishes
covering from 10450.000 to 10452.000 MHz originally made for AO40
never tested on it and now becaming rusty on the roof as you can see at
i8CVS in QRZ.com

>From your block diagrams written in finnish I see that 10.450 GHz is still
there and I am very happy with it.

Here is your original text written for AMSAT-BB on 11 may 2008  

> There is some contradicting information around regarding the
> S band receiver and X band transmitter, but here are the frequencies
> the engineering and flight models are being synthesized and
> crystalled for as per our efforts to get at least the X band
> downlink to a more "standard" frequency:

> Center Frequencies for the IF center frequency of 10.700 MHz:

> U/D           Mode        Center Frequency    Bandwidth

> Uplink        Coherent    2438.567 MHz        ~2 MHz
> Uplink        Linear      2439.000 MHz        38 kHz
> Downlink      Coherent    10451.000 MHz       ~2 MHz
> Downlink      Linear      10451.000 MHz       ~2 MHz
> Beacon        BPSK        10451.030 MHz       NB, Modulation dependent

> These frequencies were last published in the AMSAT-DL Journal
> Nr.4 Jg.33, any other public sources may be unreliable.

> 73's Michael, OH2AUE
> "Life is too short for Sudoku"

Tanks for your information and  73" de

i8CVS Domenico

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