Funcube-1 is +10 kHz on the uplink?
Just wondered if I saw this observed/reported already:
When for the Funcube-1 transponder using: 435.140 MHz uplink (LSB) 145.960 MHz downlink (USB) I still need to add another 10kHz on the uplink (making it 435.150 MHz).
Can anyone else confirm (or counter :-)) this ?
Henk, PA3GUO The Netherlands
Hi Henk,
What you are seeing is the combined effect of various oscillators drifting over temperature and some static offsets present. It is not so easy to have these offsets quantified as static numbers.
The oscillators were designed to be extremely low power, and temperature compensation is therefore limited. we do not have the power on board for PLL based frequency generation. With the current state of the art, this is possible, but not when the circuit was designed.
The power budget of a one Unit CubeSat is challenging, and FUNcube is the first 1U CubeSat to include a linear transponder. At the moment we are nice and power positive, but the system was designed with the degradation of the battery and solar arrays in mind.
So in the end, I am afraid you will have to guesstimate based on temperature.
Wouter PA3WEG FUNcube transponder designer
On Fri, Dec 27, 2013 at 10:05 PM, PA3GUO [email protected] wrote:
Just wondered if I saw this observed/reported already:
When for the Funcube-1 transponder using: 435.140 MHz uplink (LSB) 145.960 MHz downlink (USB) I still need to add another 10kHz on the uplink (making it 435.150 MHz).
Can anyone else confirm (or counter :-)) this ?
Henk, PA3GUO The Netherlands
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Thanks for the explaination Wouter. It sure is a fantastic transponder!
Henk, PA3GUO
ps: indeed as stated everywhere: 5W uplink is more than enough for a strong downlink.
Van: Wouter Weggelaar [mailto:[email protected]] Verzonden: zondag 29 december 2013 22:53 Aan: PA3GUO CC: AMSAT-BB Onderwerp: Re: [amsat-bb] Funcube-1 is +10 kHz on the uplink?
Hi Henk,
What you are seeing is the combined effect of various oscillators drifting over temperature and some static offsets present.
It is not so easy to have these offsets quantified as static numbers.
The oscillators were designed to be extremely low power, and temperature compensation is therefore limited. we do not have the power on board for PLL based frequency generation. With the current state of the art, this is possible, but not when the circuit was designed.
The power budget of a one Unit CubeSat is challenging, and FUNcube is the first 1U CubeSat to include a linear transponder.
At the moment we are nice and power positive, but the system was designed with the degradation of the battery and solar arrays in mind.
So in the end, I am afraid you will have to guesstimate based on temperature.
Wouter PA3WEG
FUNcube transponder designer
On Fri, Dec 27, 2013 at 10:05 PM, PA3GUO [email protected] wrote:
Just wondered if I saw this observed/reported already:
When for the Funcube-1 transponder using: 435.140 MHz uplink (LSB) 145.960 MHz downlink (USB) I still need to add another 10kHz on the uplink (making it 435.150 MHz).
Can anyone else confirm (or counter :-)) this ?
Henk, PA3GUO The Netherlands
_______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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