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Re: P3E Microwave Frequencies

----- Original Message ----- 
From: "Michael Fletcher" <oh2aue@sral.fi>
To: <amsat-bb@amsat.org>
Sent: Sunday, May 11, 2008 9:23 PM
Subject: [amsat-bb] Re: P3E Microwave Frequencies
> 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

Hi Michael, OH2AUE
I am very happy for the X band downlink centered at 10451 MHz and I
tank you very much for it because I can use the same downconverter
10450-10452 MHz with a 60 cm dish that I have built for AO40 long
time ago before AO40 was launched  and never used for it but still
waiting for the future over the roof.

I am less happy for the S band uplink linear centered at 2439.000 MHz
because for AO40 I have built a transverter for 2400-2402 MHz with
a 10 watt linear amplifier that I used extensively for downlink on AO40
but only one time for the uplink in mode S/K to demostrate in a scheduled
test that the onboard S-band receiver was efficient.

By the way I know that the primary purposes to change the old S band
uplink frequency choosen for AO40 is to test with P3-E the S/X band
transponder for P5-A in a fixed  selected pair of frequencies to get a
coherent mode so that if we want to save 10451.000 MHz for downlink
then 2439.000 MHz for the uplink is mandatory for you in order to use
two syncronized high power  2450.000 MHz magnetrons designed for
microwave oven.

If the S/X transponder with 38 kHz BW will be used extensively in linear
mode for the amateur use on P3-E only then I will build a new transmit
converter for 2439.000 MHz and a new linear amplifier for it.

Best 73" de

i8CVS Domenico

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