[amsat-bb] Re: FUNcube telemetry performance?
Hi John, W0JAB On AO40 you should remember mostly the fading due of spin modulation.. WOW..WOW.WOW.. because of rotation of the satellite over the Z axis ! ! 73" de i8CVS Domenico - Original Message - From: "John Becker" To: Sent: Sunday, April 20, 2014 12:42 AM Subject: [amsat-bb] Re: FUNcube telemetry performance? > I guess I was lucky I dont recall any fading with AO 40. > > On 4/19/2014 4:33 AM, Phil Karn wrote: > > I haven't done anything with AO-73, but I understand it's transmitting > > the FEC format I originally designed for AO-40. > > > > How well is it working? What fraction of the frames are successfully > > decoded? How bad is the fading? I designed my format specifically for > > the spin fading on AO-40, and if the fading due to the tumbling of a > > cubesat is too slow my format won't be able to fix it. > > > > Phil > > > > ___ > Sent via AMSAT-BB@amsat.org. 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 ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] "Alaskan Arrow" now available from Arrow Antennas
It looks like the "Alaskan Arrow" 146/437-14 with 4 elements on 2 meters and 10 elements on 70 cm is now available as a regular item from Arrow Antennas. It had previously been a special order item only. http://www.arrowantennas.com/arrowii/alaskanarrow.html 73, Paul, N8HM ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] Re: FUNcube telemetry performance?
I guess I was lucky I dont recall any fading with AO 40. On 4/19/2014 4:33 AM, Phil Karn wrote: I haven't done anything with AO-73, but I understand it's transmitting the FEC format I originally designed for AO-40. How well is it working? What fraction of the frames are successfully decoded? How bad is the fading? I designed my format specifically for the spin fading on AO-40, and if the fading due to the tumbling of a cubesat is too slow my format won't be able to fix it. Phil ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] FUNcube telemetry performance?
Phil, I have been monitoring the FC telemetry pretty closely and have some observations for what it is worth: 1.The last update to the Dashboard produced marked improvement in decoding the telemetry. 2.Using an IC910, M^2 14-element RHCP yagi with antenna mounted preamp, I typically decode around 120 frames and lose around 10 frames. 3.Using the FCD with a simple turn-style RHCP with antenna mounted preamp, I will get approximately one third the performance of the main station setup. Using a simple antenna with no preamp I get dismal performance with the FCD. 4.Of course I have more success decoding the telemetry when the bird is in the daylight mode than when operating in the night/transponder mode. 5.I have not noticed any significant fading of the signal with the M^2 setup except some minor fading at AOS/LOS. I will get fading using the turn-style however the fades appear to be due to the nulls in that antenna pattern more than due to fades from the satellite. However, the reduced signal strength helps to emphasize the fades with the turn-style. 6.I estimate that it takes a minimum of 50 decoded frames to capture a full set of whole orbit data. It requires a significant number of additional frames to capture usable high resolution data during a pass (I define a usable data set as being able to determine the rotation rate of the satellite from the high resolution data). 7.There is significant frequency drift in the downlink frequency that tracks the temperature of the satellite internals. I also notice significant FMing of the downlink frequency when the transponder is being used (appears to track with the power used by the transponder). The Dashboard does a pretty good job of compensating for these frequency deviations, I haven't noticed any significant loss of data due to this FMing. The frequency drifting needs some attention when using a traditional rig under computer control (the drift is beyond Doppler). When using the FCD, the Dashboard takes care of the temperature drift issue. One of the many interesting things that I am monitoring on this bird is the rotation rate. The bird started out with a rotation rate of .4 RPM, then something happened on or about December 28th and the rotation abruptly started to slow down to a minimum rate of .12 RPM (or 8.5 minutes per revolution) around the end of January, then it started to spool up again to a maximum rate of 1.16 RPM around the end of March, and then it started slowing down again.today at .65 RPM (1.54 minutes per revolution) with the curve trending down. I have taken many mind trips trying to rationalize what I am observing.but all those roads are leading somewhere near Albuquerque and I have no reason to go there (nice place though hihi). Let me know off line if you would like the graphics of my rotation study. Mark Spencer, WA8SME mspen...@arrl.org ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] Re: FUNcube telemetry performance?
Overall I'll take funcubes telemetry over any AFSK bird It's extremely simple to receive and in my opinion it's much better than I've ever had luck on an AFSK bird. On Saturday, April 19, 2014, Joe Fitzgerald wrote: > Phil, > > That is an interesting question. I have fooled with a simple 1/4 wave > vertical, and observe very bad fading with a period of 10's of seconds (5 > to 10 times longer than individual frames). It seems to my ear that > signals need to be pretty strong in order to decode on AMSAT-UK's > "dashboard" software. > > -Joe KM1P > > On 4/19/2014 5:33 AM, Phil Karn wrote: > >> I haven't done anything with AO-73, but I understand it's transmitting >> the FEC format I originally designed for AO-40. >> >> How well is it working? What fraction of the frames are successfully >> decoded? How bad is the fading? I designed my format specifically for >> the spin fading on AO-40, and if the fading due to the tumbling of a >> cubesat is too slow my format won't be able to fix it. >> >> Phil >> >> ___ >> Sent via AMSAT-BB@amsat.org. 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 >> > > ___ > Sent via AMSAT-BB@amsat.org. 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 > ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] Re: FUNcube telemetry performance?
Phil, That is an interesting question. I have fooled with a simple 1/4 wave vertical, and observe very bad fading with a period of 10's of seconds (5 to 10 times longer than individual frames). It seems to my ear that signals need to be pretty strong in order to decode on AMSAT-UK's "dashboard" software. -Joe KM1P On 4/19/2014 5:33 AM, Phil Karn wrote: I haven't done anything with AO-73, but I understand it's transmitting the FEC format I originally designed for AO-40. How well is it working? What fraction of the frames are successfully decoded? How bad is the fading? I designed my format specifically for the spin fading on AO-40, and if the fading due to the tumbling of a cubesat is too slow my format won't be able to fix it. Phil ___ Sent via AMSAT-BB@amsat.org. 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 ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] Re: Any latest news on the Cubesats that fly with SpaceX CRS-3 mission
AMSAT-UK is on top of this 108-satellite payload! (That's five CubeSats ... one with 104 Sprite satellites!) http://www.amsat-uk.org Clint K6LCS http://www.hamradioprogramming.com ___ Sent via AMSAT-BB@amsat.org. 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
[amsat-bb] FUNcube telemetry performance?
I haven't done anything with AO-73, but I understand it's transmitting the FEC format I originally designed for AO-40. How well is it working? What fraction of the frames are successfully decoded? How bad is the fading? I designed my format specifically for the spin fading on AO-40, and if the fading due to the tumbling of a cubesat is too slow my format won't be able to fix it. Phil ___ Sent via AMSAT-BB@amsat.org. 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
