July 2011 - AMSAT-BB - mailman.amsat.org

AO-7 Mode A vs. Mode B Performance
by John Papay 27 Jul '11

27 Jul '11

There is a huge difference in signal quality between Mode A and Mode B on AO-7. I've been working Europe on Mode A days and have found that the audio quality is excellent. I've experimented with higher power levels to see how the transponder performs and have found that it can handle the highest power levels on the uplink without fm'ing, distorting or creating images across the passband. Of course it is harder to hear with severe fading on a horizontal beam antenna, but it is very usable. This morning there were three French stations on in Mode A. F6FLE was pounding away on CW and loud. But there was no apparent degradation of the other voice stations using the transponder at the same time. Strong CW on Mode B just kills voice readability and strength on other stations. No images were heard, the passband was quiet except for other ham radio transmissions. I have several antennas for 10m. The one I use for Europe is a 5 element beam at 120'. It can see the horizon in all directions and can hear AO-7 when it is below the horizon. For higher elevations I use a single element at about 15 feet. The Mode B transponder never sounds very good. And it seems to be in a power limited situation even when there are no ham radio transmissions in the passband. What you do hear is all kinds of noise and I suspect this noise is the culprit in robbing all of the available power to run the transmitter. The noise moves and is probably being received from ground sources, hence the apparent doppler. User stations sound choppy even when running minimal power. When you run more power, signals FM and images are heard within the passband. The question is what is the source of all the crud that AO-7 is hearing in Mode B? After all, 432 is supposed to be used for weak signal operation and should be very quiet. Are there issues within the satellite that contribute to this? If you were a user of AO-7 back in the 70's, what was Mode B like back then? Of course it had a better power source when the batteries were still functional, but was the signal/audio quality much better? Did it FM and was the audio choppy? We are very fortunate to have AO-7 regardless of the performance issues. It is challenging to work at low elevations but the payoff is worth it. What we would really appreciate here in North America is more activity from Europe on the passes that reach the across the Atlantic. Last week I had a qso with IK8YSS in Mode B, 7554KM. I have seen his callsign in the AO-7 logbook for a long time and finally we had a mutual window with good conditions. LA4FPA/p was on yesterday as promised from JP22. AO-7 might not be the HEO that many wish we had, but it is the highest bird we have right now. Let's use it while we still have it. 73, John K8YSE

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Re: G5400 elevation issue
by i8cvs 27 Jul '11

27 Jul '11

----- Original Message ----- From: Dave Webb KB1PVH To: i8cvs Sent: Tuesday, February 08, 2011 3:36 AM Subject: Re: [amsat-bb] G5400 elevation issue Domenico, The highest voltage that I can get at full 180° flip is 2.78 volts with voltage adjustment pot on rear of controller box. Dave - KB1PVH Hi Dave, KB1PVH Make the following troubleshooting : Measure please the DC voltage across E2 and E1 with the antennas at full 180° flip.Since the display on the control box reads correct elevation you must read about 5 volt DC. By the way since as measured between pin 1 and 8 of the external control DIN connector and with the voltage adjustment of pot VR4 you can get only 2.78 volt at full 180° flip it means that there is someting damaged across the operational amplifier Q4 4558 1/2 Since the pot VR4 is 10 k and there is a 4.7 k fixed resistor in series of it if you measure the voltage across VR4 you should get about 3.3 volt DC By the way measuring the voltage between the wiper of VR4 and the ground you should get a voltage change between 5 volt to 3.3 volt while rotating VR4 fully 270° back and forth If this is the case than the operational amplifier Q4 4558 1/2 do not correctly amplify the DC input signal applied to Q4 input pin 3 from the wiper of VR4 Measure the DC voltage between output pin 1 an ground of Q4 and rotating VR4 by 270° back and forth you should get and amplified voltage greater than 5 volt DC and if not check diodes D22-D23-D24-D25 and all components connected around Q4 If all components diodes-resistors and capacitors are nominal than it is possible that Q4 has lost amplification. In this case change the 47 k feedback resistor R39 with a 100 k resistor and the amplification will increase at a point that flipping the antenna at full 180° the voltage across pin 1 and 8 of the DIN external connector will rise up to 5 volt DC or more. Have fun 73" de i8CVS Domenico On Feb 7, 2011 7:46 PM, "i8cvs" <domenico.i8cvs(a)tin.it> wrote: > ----- Original Message ----- > From: "Dave Webb KB1PVH" <kb1pvh(a)gmail.com> > To: "AMSAT -BB" <amsat-bb(a)amsat.org> > Sent: Monday, February 07, 2011 5:16 PM > Subject: [amsat-bb] G5400 elevation issue > > > The display on the control box reads correct elevation, but on my digital > display on the Easy Rotor Controller shows erratic elevation position. I > have recalibrated it several times with no success. It won't read any > elevation until it is around 20° give or take. It also seems to have become > worse since our really cold temps set in. My best guess is the pot in the > rotor, but not sure where to start in the process. > > Thanks in advance > > Dave - KB1PVH

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Re: ISS Message Board,
by Nader Omer 27 Jul '11

27 Jul '11

Hi It was so interesting to work ISS BBS over Africa :) ( Only You ) http://www.amsat.org/amsat/archive/amsat-bb/200901/msg00853.html More interest than ISS was AO-51 9k6 Pacsat mode . I really miss it. http://www.st2nh.com/photos 73's Nader

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FAST2
by Fred VE3FAL 27 Jul '11

27 Jul '11

I copied a data line tonight at 03:55 EST while at work. The data was from FAST2 (EMMA) on 145.825, first time copying this data. Fred CIW649/VE3FAL CFARS Member SATERN Member SATERN Amateur Radio Liaison Officer DEC Amethyst District ARES SKCC QRP Awards Manager SKCC#50 http://www.skccgroup.com RU QRP Club # 285

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ARISSat-1 Battery Charging
by Clint Bradford 27 Jul '11

27 Jul '11

At the top of today's schedule for the Russians aboard the ISS ... "Operations and experiments on the International Space Station July 27, 2011 - On July 27 the Russian segment of International Space Station, astronauts plan to continue their work to prepare for spacewalk (leak check suits, ping, and medical settings via spacesuits and equipment in the docking compartment, "Pierce" and the transitional compartment service module "Zvezda", charging unit supply for micro "Cedar"), control mikroekosfery habitat connectivity DPO ship "Progress M-11M" to the management and maintenance of the ISS coolant ... " Clint Bradford, K6LCS http://www.work-sat.com

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Solar Flare prediction
by Lee Maisel 27 Jul '11

27 Jul '11

This is kind of related to satellites generally, and may have been discussed here before, but I was flabbergasted, and had to share. Very interesting. And to be able to predict solar flares a day and a half before they erupt can prove very useful!! http://news.stanford.edu/news/2010/august/sun-082310.html Lee W5LMM

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ISS BBS/Message Board
by Kevin Deane 26 Jul '11

26 Jul '11

So the general opinion on here and from some people across the world is that using the BBS ruins the pass for basicly everyone in the footprint. Well after my friend in Reno could not get a message on while I was on the BBS and myself while he was on it, I can see the truth of the matter is clear. I am new to radio and Packet/APRS, learning and having fun. I will just have fun blastin away at the message board and hope to catch someone at there keyboard. I do sympathize with anyone who was not able to get on while I was getting messages from actual people that helped me get started with Packet in France and the Czech Republic. I will stay off the BBS, unless in the future if I find someone who wishes to have a Digi Qsl via ISS BBS who is outside my footprint, then at least I will KNOW I am being selfish and will enjoy hogging the ISS only just a little bit less now. Kevin KF7MYK

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Special Event Station N8M Active on Satellites This Weekend
by JoAnne Maenpaa 26 Jul '11

26 Jul '11

Hello Everyone, Here is an interesting item. If we waited for the weekend ANS news cycle this special event activity would be already be over ... Ford Amateur Radio League, along with other local radio clubs, will be active during the weekend of July 30th & 31st with the special event call of N8M located at the Detroit Maker Faire at the Henry Ford Museum of Dearborn Michigan. Operating modes will be HF/VHF/SAT/EME CW/VOICE/DIGI conditions permitting. We hope to work as many Satellites as possible with the special call. For more info, go to http://www.thehenryford.org/events/makerFaire.aspx (or) http://www.k8utt.org/index.htm For more info, contact N8NWA(a)Yahoo.com -- 73 de JoAnne K9JKM k9jkm(a)amsat.org Editor, AMSAT News Service

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ARISSatTLM Morse Code Decoder Works on HF Also
by JoAnne Maenpaa 26 Jul '11

26 Jul '11

Hello Everyone, Did you know that the Morse Code Decoder window in ARISSatTLM will also decode Morse on the HF bands? I was tuning around the low end of 20M and decided to give it a try. I'm already setup for PSK31 and JT65 on my FT857D so the audio path between the rig and computer soundcard is setup over here. Here is what I did ... 1. Start ARISSatTLM 2. Click the start button in the lower left of the Tuning Indicator window. 3. Tune your HF receiver to put the CW signal in the display where it says "Put CW Signal Here" 4. Nice steady CW like the ARRL bulletins decodes nicely. I let it run for a minute and the buffer scrolled nicely through the display. Reading the CW bulletin was like reading the mail :-) Short bursty 50 WPM QRZ 5NN contest type operation missed a few characters. Perhaps it was just a weaker signal since I was looking for ST0R. You can get the ARISSatTLM software from http://www.arissattlm.org/. There is a link on the http://www.amsat.org front page to get a copy of the software Quick Start Guide. Have fun! -- 73 de JoAnne K9JKM k9jkm(a)amsat.org

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Cubesat NANOSATC-BR
by ps8rf Piraja 26 Jul '11

26 Jul '11

Brazil is preparing to launch the NANOSATC-BR. The design of the BR-NANOSATC is being developed by the National Institute for Space Research (INPE) and students of Federal University of Santa Maria (UFSM) of state Rio Grande do Sul here in Brazil. "The BR-NANOSATC will have two scientific instruments, a magnetometer and also a particle detector of precipitation for monitoring real-time geospatial, and the precipitation of particles in the magnetosphere disturbances on the Brazilian territory to determine its effects on regions such as the South Atlantic Magnetic Anomaly (SAMA, the English acronym) and the Brazilian sector of the equatorial electrojet. This anomaly [SAMA] is a "failure" of the Earth's magnetic field in this region, which is about Brazil, "said Jose Manuel Octavio Coordinator of the National Institute for Space Research of Brazil. As a consequence of this anomaly, there is a greater risk of the presence of particles high-energy region, which can affect communications, signals from global positioning satellites (like GPS), or even cause failure of electronic equipment such as onboard computers. The INPE has been studying this anomaly for decades, including several researchers international reputation, which even took part in defining the mission and its payload. " According to Otavio Durão, Technical Coordinator NanosatC-Br and INPE, the situation referred to is its launch in November 2012. The uplink frequency (UHF) and downlink (VHF) have been allocated by the IARU. The telemetry will be at 145.865 MHz 9k6 BPSK. The project is receiving support from the Amateur Radio Association Santamariense - ASRA and call sign of the control station will be PY3EB. Durão told me it will be very interesting and welcome the participation of the Amateur Radio satellite tracking. We are waiting for soon the website with all the information the CubeSat NANOSTC-BR. The project is in full swing. IARU Informations: http://www.amsatuk.me.uk/iaru/finished_detail.php?serialnum=209 73' Pirajá, PS8RF The Amateur Radio is supportive and helpful in any circumstance.

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