----- 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