AMSAT-BB May 2013

123 participants
203 discussions

Subject: Is there anyway to get the transponder on the ISS working again ?

by K5VOU

Let me summarize what I think was said in answer to my question; "Is there any way to get a linear transponder on the ISS?" 1.) There is already a transponder on the ISS albeit an FM U/V one. 2.) It is not in use because it is either: a.) a 'power hog' or b.) it is not functioning properly or c.) NASA does not want it functioning as an open repeater. Amsat has the resources to fix a.) and b.) but perhaps not c.) ( although we do have a liaison to NASA for such things I believe.) So the next question is; "Who at Amsat can talk to NASA about a solution?" Tom K5VOU

9 years, 2 months

Re: Is there anyway to get a linear transponder on the ISS? (PSK31)

by Robert Bruninga

> The nicest configuration... would be a 2m FM uplink with CTCSS to avoid interference and a SSB 10m downlink. The problem with that is the same as all our other FM satellites. Only a single user at a time. Congestion, conflict and little practical value. The better use of SSB is to use the same single channel FM bandwidth for a wideband transponder allowing up to 30 or more simultaneous users. This is equally trivial to do. Just connect the output of a 10m SSB receiver tuned to 28.120 MHz to an FM downlink and use PSK-31 on the uplink. The FM downlink gives everyone in the footprint the identical PSK waterfall spectrum where they can tune all 30 QSO's simultaneously. Then each person sets their PSK-31 uplink to an unused 100 Hz wide area in the spectrum Not only can 30 stations participate at once, the fact that they are transmitting on 10m PSK31 and receiving on 2m or UHF FM at the same time means they are also operating full duplex during the entire pass. Everyone can talk to everyone without conflict or congestion. And no special hardware is required for users. A PC with a sound card can do it all. Bob, WB4APR

9 years, 2 months

Grid trip to DN64, WY

by Rodney Waln

hi amsaters, i will be going to the Wyoming State ham fest in buffalo in the northern part of the state, dates will be june 6 and 7th, 2013 grid DN64 and could go down and over to other grids if requested, i would like to setup sceds on any of the operational satellites, those stations needing the grids will be called, and any one else that needs these grids is welcome also to give a shout, other travelers have given me these grids in the past and i am returning the faver, you know who you are thank you. Rodney kc0zhf DN71

9 years, 2 months

. Re: International Space Station-Bounce on 1296 MHz

by i8cvs

Von: i8cvs [mailto:[email protected]] Gesendet: Donnerstag, 30. Mai 2013 01:13 An: Andreas Imse Betreff: Re: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz Wichtigkeit: Hoch Hi Andreas, DJ5AR Using the RADAR equation I would like to perform a link calculation of your QSO with Jan PA3FXB through the International Space Station-Bounce on 1296 MHz I already know that the gain of your 3 meter dish is 29 dB and your power at the feed point is 200 W but I need the additional estimated following informations: 1) The range and the elevation from the ISS and your QTH as soon you started receiving your own ECHO'es signals. 2) The maximum range and the elevation from the ISS and your QTH when your received signals were the strongest possible. 3) Were you receiving in analogic CW using 500 Hz filter and headphone or were you using digital WSJT software such as FSK441 or others software (commonly used for rapidly moving meteor scatter QSO's). ? When the ISS is at the AOS with elevation of 2 degrees the range is about 2000 km and when the elevation is about 35 degrees the range is about 700 km so that I plan to calculate the budged link for a range 700 km and see what the results are in Signal to Noise ratio using only a analogic CW receiver and than calculate the advantages using a digital system. Thanks for your answere. 73" de i8CVS Domenico ----- Original Message ----- From: Andreas Imse To: domenico.i8cvs(a)tin.it Sent: Tuesday, May 28, 2013 9:23 AM Subject: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz Hi Domenico, I saw your posting and will give you a short reply. We are both using 3 m dishes, 200 W here and 375 W on Jan´s side. That was far enough for our tests. As our QTHs are quite close (only 367 km), it is possible that QSOs over a larger distances might be possible with less power like in aircraft scatter. If you are equipped for 1296 MHz and able to track the ISS with your antenna, we should have a try. Doppler compensation can be done completely on my side. vy 73, Andreas DJ5AR / EI8HH dj5ar(a)darc.de www.dj5ar.de ----- Original Message ----- From: "Andreas Imse" <andreas(a)imse.de> To: <amsat-bb(a)amsat.org> Sent: Thursday, May 30, 2013 10:20 AM Subject: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz Hi Domenico and all others, interested in this subj I am not looking for completing QSOs only and would like to test with receiving stations too. if you have an antenna for 1296 MHz and are able to do ISS tracking, we can try. I can perform the complete doppler compensation as well for uplink as for downlink here. So the receiving station may stay and listen on a fixed frequency ( e.g. 1296,300 MHz). vy 73, Andreas DJ5AR / EI8HH mailto:[email protected]> dj5ar(a)darc.de -------------------------------------------------------------------------- Hello Andreas, DJ5AR / EI8HH Using the data of your station and that of Jan PA3FXB I was able to compute the Link Budged calculations for the international Space Station-Bounce on 1296 MHz LINK BUDGED CALCULATIONS by i8CVS We consider the ISS like a passive reflector with reflectivity factor of 10 % to try a QSO by reflection Earth-ISS-Earth DATA: 1) The solar panels of the ISS plus the central body large like a Boeing 747 have a metallic reflecting surface of about 2000 square meters and we consider the ISS like a circular RADAR target having being a metallic plate an estimated reflectivity factor S of 10 % at SHF 2) The range EARTH-ISS at elevation of 35 degrees is about 700 km 3) Our EME station at 1296 MHz uses a 3 meters dish in diameter with gain of 29 dB and 200 W at the feed 4) The overall noise figure of our receive system is NF = 0.5 dB while the antenna temperature is 50 kelvin when pointed at the Cold Sky and we receive on CW using a filter with a BW large 500 Hz 5) We use only analogic reception without digital software like WSJT or similar tecniques. CALCULATION PROCEDURE : Aiming the dish towards the ISS when distant 700 km and transmitting on CW and using the RADAR equation we calculate the Signal to Noise ratio S/N to see if on CW the echoes reflected by the ISS are above or belove the Noise Floor of receiver. First of all using the RADAR equation we calculate the round trip attenuation in dB between EARTH-ISS-EARTH when approaching to TCA the average range is 700 km RADAR EQUATION Pt x Gt x Ar x S Pr = ----------------------------- ( 4 x 3.14 x R^2 ) ^2 Where : Pr = power received in watt Pt = power transmitted = 1 watt Gt = isotropic gain of a ground antenna at 1296 MHz = 1 time in power or 0 dB Ar = aperture area of isotropic antenna at 1296 MHz = 0,0043 square meters S = Sigma or Radar Cross Section i.e. the surface of the ISS in square meters with reflecting coefficient of 0.10 = 10 % R = distance or range EARTH-ISS = 700 km = 700000 meters NOTE: (4 x 3.14 x R^2)^2 calculates the surface of a sphere having a radius R=700000 meters elevated time 2 to take account of the round trip "EARTH-ISS-EARTH" CALCULATION OF ATTENUATION "EARTH-ISS-EARTH" : S = Sigma of the ISS with reflecting surface of 2000 square meters and reflection coefficient of 10 % = 2000 x 0.10 = 200 square meters Calculation of the aperture area Ar of isotropic antenna at 1296 MHz / 2 2 /\ 0,2314 Ar = ---------- = ----------- = 0,0043 square meters 4 x 3,14 4 x 3,14 Calculation of the received power Pr on the EARTH collected by the isotropic antenna at 1296 MHz 1 x 1 x 0.0043 x 200 -26 Pr = --------------------------------- = 2.27 x 10 watt (4 x 3.14 x 700000^2 )^2 Calculation of the attenuation Att for the Round-Trip EARTH-ISS-EARTH Pt (1watt) 25 Att = --------------------- = 4.41 x 10 time in power -26 2.27 x 10 watt 25 and in dB the Att = 10 log 4.41 x 10 = 256.4 dB 10 CALCULATION OF THE OVERALL NOISE FLOOR FOR THE RECEIVER : Data of the 1296 MHz receiving system : Overall Noise Figure of receiving system NF= 0.5 dB = 35 kelvin Bandwidth BW of receiver on CW = 500 Hz Equivalent Noise Temperature Ta of the antenna when aimed toward the Cold Sky = 50 kelvin Calculation to get the Noise Floor KTB of receiver Where : -23 K = Boltzmann constant = 1,38 x 10 joule/kelvin T = Equivalent noise temperature Ta of the antenna plus the equivalent Noise Temperature Te of receiver i.e. T= (Ta + Te) Computation of the overall Noise Factor F for the receiver F = 10 ^ (NF/10) and so F = 10 ^(0,5 / 10) = 10 ^0,05 = 1,12 in factor The equivalent overall Noise Temperature Te of the receiver is Te = ( F-1) x 290 = (1,12 -1) x 290 = 35 kelvin The overall Noise Floor KTB of the receiving system with the antenna connected is : KTB = K x ( Te + Ta ) x BW and in numbars : -23 Noise Floor KTB = 1,38 x 10 x ( 35 + 50 ) x 500 = -182.3 dBW LINK CALCULATION "round trip" EARTH -ISS-EARTH at 1296 MHz on CW TX power at feed.................................+23 dBW = 200 watt Antenna Gain in TX................. ...........+29 dBi ------------ EIRP transmitted to the ISS. ..............+52 dBW = 158.5 kW Attenuation EARTH-ISS-EARTH... - 256.4 dB ------------- Power Pr received on EARTH over isotropic antenna ............................ - 204.4 dBW Antenna Gain in RX......................... + 29 dB ------------ Power incident at receiver input ...... - 175.4 dBW RX Noise Floor......................... ........- 182.3 dBW ------------ S/N ratio CW at RX audio output... + 6.9 dB CONCLUSION : At a range of 700 km from the ISS and using a 3 meters dish with 200 W at the feed and a receiving system with a Noise Floor of -183.3 dBW = - 153.3 dBm it is possible to hear your hown echo signals in plain analogic CW with a Signal to Noise ratio S/N of +6.9 dB wich is very strong. If two stations are equipped with the same equipments it is possible to make good QSO for a short time when the ISS is close range around 700 km at elevation of about 35 degrees. Increasing the BW of receiver at 2700 Hz to try receive SSB it is very difficult since the signal reflected back by the ISS will be very noisy with a S/N ratio of about - 0.5 dB and so belove the Noise Floor of your receiver. It is necessary to use a precise traking system particularly fast to move the dish as soon the ISS approach the TCA because the beam wide of a 3 meter dish with gain of 29 dB is large only about 5 degrees at the -3 dB points so that traking the ISS at 1296 MHz with a 3 meter dish or even larger for EME it seems to be the more critical point. 73" de i8CVS Domenico

9 years, 2 months

ANTELSAT a SSTV CubeSat from Uruguay

by M5AKA

Another CubeSat planning a Yasny Dnepr launch this year. ANTELSAT has an AX.25 packet radio digipeater and a 70cm SSTV downlink. See http://amsat-uk.org/2013/05/30/antelsat-sstv-cubesat/ ---- 73 Trevor M5AKA AMSAT-UK website http://amsat-uk.org/ Facebook https://www.facebook.com/pages/AMSAT-UK/208113275898396 Twitter https://twitter.com/AMSAT_UK ----

9 years, 2 months

Québec provincial Hamfest

by lucleblanc6＠videotron.ca

The Quebec provinvial hamfest will be held sunday june 2 2013 in Sorel-Tracy. Sponsored by the Sorel-Tracy VE2CBS ARC who will present the first EME class PORTABLE station. For more info visit http://www.hamfest.qc.ca/Hamfest/Accueil.html http://www.ve2cbs.qc.ca/VE2CBS/Nos_albums/Pages/Projet_%22Objectif_Lune%22.… Luc Leblanc VBE2DWE

9 years, 2 months

CubeBug-2 hopes for Nov. 2013 Yasny Dnepr launch

by M5AKA

CubeBug-2 will carry an AX.25 packet radio digipeater for amateur radio use, See http://amsat-uk.org/2013/05/30/cubebug-2-november-dnepr/ ---- 73 Trevor M5AKA AMSAT-UK website http://amsat-uk.org/ Facebook https://www.facebook.com/pages/AMSAT-UK/208113275898396 Twitter https://twitter.com/AMSAT_UK ----

9 years, 2 months

Re: International Space Station-Bounce on 1296 MHz

by Andreas Imse

Hi Domenico and all others, interested in this subject. I am not looking for completing QSOs only and would like to test with receiving stations too. if you have an antenna for 1296 MHz and are able to do ISS tracking, we can try. I can perform the complete doppler compensation as well for uplink as for downlink here. So the receiving station may stay and listen on a fixed frequency ( e.g. 1296,300 MHz). vy 73, Andreas Andreas Imse DJ5AR / EI8HH Hinter der Kirche 31 55129 Mainz Germany +49 6136 959025 <mailto:[email protected]> dj5ar(a)darc.de <http://www.dj5ar.de> www.dj5ar.de

9 years, 2 months

Re: International Space Station-Bounce on 1296 MHz

by Andreas Imse

Hi Domenico, your plan is really interesting, but I cannot support you with exact data at present. Maybe the wav file recorded by my SDR can give you an impression of the QSO: https://docs.google.com/file/d/0B8ak4za2va9ZVld5ZXZaREE5bXc/edit?usp=sharing I did not receive own echoes off the ISS, just the ones of PA3FXB, who was using a 3 m dish as well and 375 W at feed. We used plain CW and I heard Jan on my speaker with 2700 Hz Bandwidth. As it was the very first shot, just to complete a QSO, no semi scientific records were made, hi. There were too many other things to mention about. But it is a good idea to record all data as current elevation, azimuth, slant range, relative speed and doppler to a file. Since I do the complete station control including CW transmission by a homebrew program, it is just a small piece of work to do, to realize that. These data could easily be synchronized with a wav file, like the one linked above, by using the switching between RX and TX. Jan and I plan further tests, when ISS will appear again at more moderate times ;-) We are thinking about FSK441 tests too, but not at present. vy 73, Andreas Andreas Imse DJ5AR / EI8HH Hinter der Kirche 31 55129 Mainz Germany +49 6136 959025 dj5ar(a)darc.de www.dj5ar.de Von: i8cvs [mailto:[email protected]] Gesendet: Donnerstag, 30. Mai 2013 01:13 An: Andreas Imse Betreff: Re: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz Wichtigkeit: Hoch Hi Andreas, DJ5AR Using the RADAR equation I would like to perform a link calculation of your QSO with Jan PA3FXB through the International Space Station-Bounce on 1296 MHz I already know that the gain of your 3 meter dish is 29 dB and your power at the feed point is 200 W but I need the additional estimated following informations: 1) The range and the elevation from the ISS and your QTH as soon you started receiving your own ECHO'es signals. 2) The maximum range and the elevation from the ISS and your QTH when your received signals were the strongest possible. 3) Were you receiving in analogic CW using 500 Hz filter and headphone or were you using digital WSJT software such as FSK441 or others software (commonly used for rapidly moving meteor scatter QSO's). ? When the ISS is at the AOS with elevation of 2 degrees the range is about 2000 km and when the elevation is about 35 degrees the range is about 700 km so that I plan to calculate the budged link for both distances 2000 km and 700 km and see what the results are in Signal to Noise ratio using only a analogic CW receiver and than calculate the advantages using a digital system. Thanks for your answere. 73" de i8CVS Domenico ----- Original Message ----- From: Andreas Imse <mailto:[email protected]> To: domenico.i8cvs(a)tin.it Sent: Tuesday, May 28, 2013 9:23 AM Subject: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz Hi Domenico, I saw your posting and will give you a short reply. We are both using 3 m dishes, 200 W here and 375 W on Jan´s side. That was far enough for our tests. As our QTHs are quite close (only 367 km), it is possible that QSOs over a larger distances might be possible with less power like in aircraft scatter. If you are equipped for 1296 MHz and able to track the ISS with your antenna, we should have a try. Doppler compensation can be done completely on my side. By the way: I have been visiting Naples and Stromboli 3 years ago and remember passing Torre del Greco with the Circum Vesuviana. vy 73, Andreas Andreas Imse DJ5AR / EI8HH Hinter der Kirche 31 55129 Mainz Germany +49 6136 959025 dj5ar(a)darc.de www.dj5ar.de

9 years, 2 months

Problems with SATPC32 CAT

by Les Rayburn

I've continued to try to troubleshoot the problem with no success. I checked and the DopplerSQF file appears to be entact. Read the manual and searched the FAQ but can't find any reason why I'd be "missing" the data in the CAT field. If I select an alternative configuration, the program seems to work fine, but that causes me to lose my settings and have to begin all over again. Any ideas? -- -- 73, Les Rayburn, N1LF 121 Mayfair Park Maylene, AL 35114 EM63nf 6M VUCC #1712 AMSAT #38965 Grid Bandits #222 Southeastern VHF Society Central States VHF Society Life Member Six Club #2484 Active on 6 Meters thru 1296, 10GHz & Light

9 years, 2 months

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AMSAT-BB May 2013