April 2008 - AMSAT-BB - mailman.amsat.org

Re: Ridge Test Results
by Laurence 'Mike' Hammer 22 Apr '08

22 Apr '08

Hi Nathaniel, Been watching this thread. The only bits of info I haven't seen go across yet -- Antennas act very differently when the radiator part of the antenna is in close proximity to the RF ground. If you have modelled the antenna as being "in empty space", that will account for much of the loss seen when it is mounted to the sat, which in your design by definition is very close to the sat frame, and thus both the electrical and RF grounds. Have your modeller check to see if they have the sat frame, and any conductive panels, in their model; if not you'll have some (possibly large) matching adjustments to do. A 1/4 wave piece of steel measuring tape needs to be at 90 degrees from all nearby metal to be an actual "monopole" antenna. If you lay it along the side of the sat, the nearby metal (grounds) will soak up much of the signal. If I remember right, Prof Campbell's prior-to-CubeSat project (name is escaping me at the moment) incorporated a proven loop design. I don't remember the freq though. You might want to check your spec against that one. If you haven't already, check the entire assembly (antenna on sat) with an SWR analyzer, or preferably a network analyzer, to make sure the transmitter is "seeing" a 50 ohm RF load at the input of the antenna line at your transmit freq. While this doesn't guarantee the antenna is actually an antenna and not a resistor, it does give a basic check that the matching network is close for your situation. GL, Mike N2VR

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IW6IBE
by Chris Bloy 22 Apr '08

22 Apr '08

Hi All, Does anyone have any details for the above station? I work him today on AO-27, but found that my recording cable fell out and only recorded wind!! Ivor is he name from memory and his callsign is IW6IBE.. I have searched the web and found nothing! Any location information would be great.. Thanks, Chris - M0DQO/P

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Re: FINAL MONTHLY OSCAR-11 REPORT
by kb2m＠comcast.net 22 Apr '08

22 Apr '08

It was a pleasure to work with you on UO-11 Clive. I still listen for her at least a couple of times a week, last time was yesterday. And, I will continue to do so in the future. 73 Jeff kb2m -------------- Original message -------------- From: Clive Wallis <clivew(a)zetnet.co.uk> > > FINAL MONTHLY OSCAR-11 REPORT > > 21 April 2008 > > RECEPTION REPORTS REQUESTED! > > In the years ahead, it is possible that you may hear OSCAR-11, by accident, > when tuning round the frequency. If you are able to record the satellite on > audio tape or as a WAV file (not MP3), please do so, as it is unlikely > that it will be heard on the next pass! > > Please send reception reports to xxxxx(a)amsat.org (replace xxxxx by > g3cwv) or post to amsat-bb. If you have a file, please let me know what > you have, before sending it! > > If you need to hear what the satellite sounds like, please visit my website > www.users.zetnet.co.uk/clivew/ The satellite transmits on 145.826 MHz. set > receiver to NBFM. > > ---------------------------- > > This is the 144th monthly report for OSCAR-11. Unless there is an > unexpected change of status (such as occured with OSCAR-7), I'm expecting > this to be my last report. > > This report covers the period from 17 March to 21 April 2008. During > this period the satellite has not been heard and no reports of reception > have been received. > > Transmissions were expected to resume on 24 March, after the beacon > switched-off on 14 March. However, permanent eclipses started a few days > beforehand, which probably caused the transmission period to be terminated > prematurely. It is now unlikely that the satellite will support any > sustained period of operation, and will only transmit for a short time, > possibly less than a single orbit, every 21 days. > > I am indebted to all those who sent reception reports during the last 12 > years. Initially there was much interest in hearing the mode-S beacon, > which was very weak. Recently, interest has changed to hearing when the > two metre beacon switched on/off. Special thanks must go to Jeff KB2M who > recorded telemetry during my holidays, and Peter ZL3TC, who has monitored > the beacon daily, during recent months. Many thanks to everyone.

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FINAL MONTHLY OSCAR-11 REPORT
by Clive Wallis 22 Apr '08

22 Apr '08

FINAL MONTHLY OSCAR-11 REPORT 21 April 2008 RECEPTION REPORTS REQUESTED! In the years ahead, it is possible that you may hear OSCAR-11, by accident, when tuning round the frequency. If you are able to record the satellite on audio tape or as a WAV file (not MP3), please do so, as it is unlikely that it will be heard on the next pass! Please send reception reports to xxxxx(a)amsat.org (replace xxxxx by g3cwv) or post to amsat-bb. If you have a file, please let me know what you have, before sending it! If you need to hear what the satellite sounds like, please visit my website www.users.zetnet.co.uk/clivew/ The satellite transmits on 145.826 MHz. set receiver to NBFM. ---------------------------- This is the 144th monthly report for OSCAR-11. Unless there is an unexpected change of status (such as occured with OSCAR-7), I'm expecting this to be my last report. This report covers the period from 17 March to 21 April 2008. During this period the satellite has not been heard and no reports of reception have been received. Transmissions were expected to resume on 24 March, after the beacon switched-off on 14 March. However, permanent eclipses started a few days beforehand, which probably caused the transmission period to be terminated prematurely. It is now unlikely that the satellite will support any sustained period of operation, and will only transmit for a short time, possibly less than a single orbit, every 21 days. I am indebted to all those who sent reception reports during the last 12 years. Initially there was much interest in hearing the mode-S beacon, which was very weak. Recently, interest has changed to hearing when the two metre beacon switched on/off. Special thanks must go to Jeff KB2M who recorded telemetry during my holidays, and Peter ZL3TC, who has monitored the beacon daily, during recent months. Many thanks to everyone. The Beacon frequencies are - VHF 145.826 MHz. AFSK FM ASCII Telemetry UHF 435.025 MHz. OFF S-band 2401.5 MHz. OFF The satellite is now subject to eclipses during every orbit. Long term predictions indicate that eclipses will occur until 2019, when there will be some eclipse free periods until 2023. However these very long term predictions should be regarded with caution, as large tracking errors can accumulate over long periods of time. When telemetry was last received it showed that one of the solar arrays had failed, and there was a large unexplained current drain on the main 14 volt bus. After 24 years in orbit the battery has undergone over 100,000 partial charge/discharge cycles, and observations suggest that it cannot power the satellite during eclipses lasting more than about ten minutes, or sometimes even during periods of poor solar attitude. The current status of the satellite, is that all the analogue telemetry channels, 0 to 59 are zero, ie they have failed. The status channels 60 to 67 are still working. The real time clock is showing a large accumulated error, although over short periods timekeeping is accurate to a few seconds per month. When last heard the clock was 83.0958 days slow. The day of the month has a bit stuck at 'one' so the day of the month may show an error of +40 days for some dates. The time display has switched into 12 hour mode. Unfortunately, there is no AM/PM indicator, since the time display format was designed for 24 hour mode. The spacecraft computer and active attitude control system have switched OFF, ie. the satellite' attitude is controlled only by the passive gravity boom gradient, and the satellite is free to spin at any speed. The watchdog timer now operates on a 20 day cycle. The ON/OFF times have tended to be very consistent. The average of many observations show this to be 20.7 days, ie. 10.3 days ON followed by 10.4 days OFF. However, poor solar attitude may result may result in a low 14 volt line supply, which may cause the beacon to switch OFF prematurely, and reset the watchdog timer cycle. When this occurs, the beacon is OFF for 20.7 days. OSCAR-11 was the second satellite from the University of Surrey, www.ee.surrey.ac.uk/SSC. It was designed, built and launched, within a time scale of six months, by a team headed by Martin Sweeting G3YJO. Amateur radio groups working at various locations in the world, also contributed to the project. It used commercially available 'off the shelf' components (COTS). Following the success of these satellites, in 1985 Surrey Satellite Technology Ltd. www.sstl.co.uk was formed, as a commercial venture. This grew into a major company which has produced over 27 small satellite projects for a global market. The University of Surrey has recently agreed to sell it's major shareholding to EADS-Astrium. This agreement is now awaiting regulatory approval. The joint company will have the experience of manufacturing large and small satellites, for geo-synchronous and low earth orbits. In regognition of his work, Martin G3YJO, was appointed Professor at the University of Surrey. He received an OBE in the 1995 Queens birthday honours list, and in 2002 a knighthood in the New Year's honours list. Listeners to OSCAR-11 may be interested in visiting my website, which is being updated to reflect the current status of the satellite. If you need to know what OSCAR-11 should sound like, there is a short audio clip for you to hear. The last telemetry received from the satellite is available for download. The website contains an archive of news & telemetry data which has now been updated. It also contains details about using a soundcard or hardware demodulators for data capture. There is software for capturing data, and decoding ASCII telemetry. The URL is www.users.zetnet.co.uk/clivew/ If you place this bulletin on a terrestrial packet network, please use the bulletin identifier $BID:U2RPT144.CWV, to prevent duplication. 73 Clive G3CWV xxxxx(a)amsat.org (please replace xxxxx by g3cwv)

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Re: Ridge Test Results
by Nathaniel S. Parsons 22 Apr '08

22 Apr '08

I'm sorry we didn't get in touch, but my cell phone died while we were out there. Were were listening on 146.610, but didn't hear anything except the time. Maybe we weren't using it correctly? If you could get all of that material tomorrow, that would be excellent. We do have access to sanding paper, a file, and a grinding wheel, though. On Mon, Apr 21, 2008 at 11:26 PM, F. Kevin Feeney <fkf1(a)cornell.edu> wrote: > Were you transmitting in just one direction or from TS to D7 and then from > D7 to TS? > Via packet, only TS to D7 (some were sent the other way, but we were told having attenuators on the RX side would give us unreliable data). By voice, both directions, and while that signal was fuzzy at higher attenuation, it never completely cut out. For the packets, we always received them on the radio, but the number recorded was the amount passed on to the computer. > Why list the power settings in each radio if you are only transmitting > from the TS2000 to the D7? That confused me. Just for completeness. > > How successful have you been at running the radios in 9600 baud mode in > previous testing? If you don't have many weeks of positive results in that > mode at this point with whatever antennas, I'd be very wary of committing to > a launch. Not very. We could complete the mission at 1200 baud, though, it would just take longer to move data back and forth. > so what are the power listings for each radio telling us? To me I think > I'm seeing that your circularly polarized antenna isn't quite as good in > horizontal mode as in vertical? You have to have less attenuation in place > to get two good packets per two tries for the same power settings in > horizontal as for vertical. looks like about a 15 db difference? (30 vs 45?) > That says your circular antenna "circularity" is suspect. Is it a helix? > Crossed yagis with phasing harness? Is it up in the air off the support > structure? Are the feedlines trailed out the back of the antenna, or do they > come down through the elements to the mast? I'm sorry that I wasn't clear, but all our rotations were in the direction of the other station. So, if an observer were looking at us from the side, Vertical: "satellite" | XXXXX- Ground Horizontal: "satellite" -- XXXXX-Ground 45 deg: "satellite" / XXXXX-Ground So we didn't really test the circularity of the ground antenna, but the gain pattern of the rubber duck. > Wait - were you testing the loop during any of this? I thought all of the > measurements were made with the rubber duck only in three orientations, > vertical, horizonatal and 45 degree. Where is the loop data shown? The loop data is the 10 dB figure mentioned in my first email. Under these same conditions on Friday, the loop only worked up to 10dB. Also, I can use a network analyzer tomorrow at 2PM. Is it worth analyzing the square loop antenna at this point? -Nate

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Fw: Re: Ridge Test Results
by Roger Kolakowski 22 Apr '08

22 Apr '08

----- Original Message ----- From: DBowman To: G0MRF(a)aol.com Cc: rogerKola(a)aol.com Sent: Tuesday, April 22, 2008 7:22 AM Subject: RE: [amsat-bb] Re: Ridge Test Results Thanks for the copy Nate. No need to reply to what follows, but it may be useful. I'll look out for the next update. Congratulations, That's really good progress for just a couple of days. I think 45dB will take you just to about 600km, but really there's room for improvement yet. The photo's show the antenna very well. A couple of thoughts. It looks like it is mounted on FR4 PCB and this is an inch or so from the main structure. Is there another antenna on the other side? - The RF will not pass through the satellite. The FR4 will affect the properties especially if you have applied glue at a voltage node on the antenna. Also, I see one side is very closely coupled into a track running from the solar cells. That will not help. My guess is that the antenna will be really bad on the VNA. - Remember when testing that the VNA will show you return loss. You will know if the return loss is between 0dB and 6dB that the antenna does not work. But please be aware that even if you see a 'good' return loss e.g. 15 to 30dB, Then that may not indicate that the energy from your transmitter is being radiated. - After all, a 50 Ohm resistor has a wonderful return loss, but does not radiate. Look for a nice dip at your design frequency. If you have to replace the antenna then a whip / steel tape would be OK but needs to work against part of the structure. - Which looking at your satellite will be difficult to do. A good solution may be to make a dipole from two solid metal rods and fit them to the same spot where your antenna is at present. - But clear of other objects. Say 1 inch above the surface. Another choice would be a folded dipole, but you will need to match that from apx 200 to 300 ohms, back down to 50 ohms. If you decide on the simple (but reliable) dipole, mount the elements off the PCB material and only support them at the center not at the ends. The ends are a high voltage point and anything near them or touching will affect the performance. I think your original estimate of 57dB is spot on. Well done. Path loss for 3.18km = -95.26dB Path loss for 2000km = -151.23 Difference from ridge to space = 56dB So you have to find another 12dB + some margin for loss due to spin or pointing angle. 1) It could be that the rubber duck is only 50% efficient. - So that could be 3dB off the total. But your new antenna may no be much better. 2) You have not mentioned ground station feeder loss. Without the preamp that will be added to the total. On 70cms you could be looking at 4 - 6dB. So, possibly only 6 or 7dB to find !!! Your TS2000 has an S meter. On SSB or CW the sensitivity is as follows. This is very approximate, but it may help. This is with RF gain at max and no pre-amp. S1 = - 113dBm at antenna. S3 - 110dBm S5 - 107 S7 - 102 S9 - 93dBm >From what you have said so far 0.5W of carrier from the ridge should give a little over S9 when in SSB or CW. If you can check this with a lab sig generator and your TS2000 you will be able to do some really good measurements on your system. I have one final thought on the missing dBs. Or the lack of 9600. You mention that you have not been able to use 9600 and you are still not 100% reliable on 1200. It could be that you need to optimize the modulation level on the transmitter. That is very important because if the modulation is too high. - i.e. if the volume going into the radio is too high, then the bandwidth on FM will be much greater then necessary. The reason this is important, is that if the transmitted bandwidth of the signal exceeds the width of the filters in the receiver, then the demodulated audio will be distorted and you will never recover the data. (I think something like this happened to CAPE 1) So, spend a little time optimizing the transmitter either by experimentation, or by calculating the bandwidth and then attaching the transmitter to a spectrum analyzer to make the adjustment. - There probably isn't time, but the proper way would be to generate a test signal at 9600 and then examine the recovered audio for distortion / linearity. Give the TS2000 a try with OSCAR 51 on 435.300 (starting 10kHz high for Doppler and finishing 10k low) April 1 - April 30 FM Repeater, V/U Uplink: 145.920 MHz FM, NO PL Tone Downlink: 435.300 MHz FM 9k6 Digital L/U BBS and Telemetry Uplink: 1268.700 MHz FM Downlink: 435.150 MHz FM Good Luck David -------------------------------------------------------------------------------- From: G0MRF(a)aol.com [mailto:[email protected]] Sent: 22 April 2008 08:44 To: DBowman Subject: Fwd: [amsat-bb] Re: Ridge Test Results In a message dated 22/04/2008 05:39:41 GMT Standard Time, nsp25(a)cornell.edu writes: I'm sorry we didn't get in touch, but my cell phone died while we were out there. Were were listening on 146.610, but didn't hear anything except the time. Maybe we weren't using it correctly? If you could get all of that material tomorrow, that would be excellent. We do have access to sanding paper, a file, and a grinding wheel, though. On Mon, Apr 21, 2008 at 11:26 PM, F. Kevin Feeney <fkf1(a)cornell.edu> wrote: > Were you transmitting in just one direction or from TS to D7 and then from > D7 to TS? > Via packet, only TS to D7 (some were sent the other way, but we were told having attenuators on the RX side would give us unreliable data). By voice, both directions, and while that signal was fuzzy at higher attenuation, it never completely cut out. For the packets, we always received them on the radio, but the number recorded was the amount passed on to the computer. > Why list the power settings in each radio if you are only transmitting > from the TS2000 to the D7? That confused me. Just for completeness. > > How successful have you been at running the radios in 9600 baud mode in > previous testing? If you don't have many weeks of positive results in that > mode at this point with whatever antennas, I'd be very wary of committing to > a launch. Not very. We could complete the mission at 1200 baud, though, it would just take longer to move data back and forth. > so what are the power listings for each radio telling us? To me I think > I'm seeing that your circularly polarized antenna isn't quite as good in > horizontal mode as in vertical? You have to have less attenuation in place > to get two good packets per two tries for the same power settings in > horizontal as for vertical. looks like about a 15 db difference? (30 vs 45?) > That says your circular antenna "circularity" is suspect. Is it a helix? > Crossed yagis with phasing harness? Is it up in the air off the support > structure? Are the feedlines trailed out the back of the antenna, or do they > come down through the elements to the mast? I'm sorry that I wasn't clear, but all our rotations were in the direction of the other station. So, if an observer were looking at us from the side, Vertical: "satellite" | XXXXX- Ground Horizontal: "satellite" -- XXXXX-Ground 45 deg: "satellite" / XXXXX-Ground So we didn't really test the circularity of the ground antenna, but the gain pattern of the rubber duck. > Wait - were you testing the loop during any of this? I thought all of the > measurements were made with the rubber duck only in three orientations, > vertical, horizonatal and 45 degree. Where is the loop data shown? The loop data is the 10 dB figure mentioned in my first email. Under these same conditions on Friday, the loop only worked up to 10dB. Also, I can use a network analyzer tomorrow at 2PM. Is it worth analyzing the square loop antenna at this point? -Nate

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CubeSats launch information
by Mineo Wakita 22 Apr '08

22 Apr '08

Launch 28Apr08 03:53UTC Launch Vehicle: PSLV-C9 Preliminary TLE 1 00000U 00000C 08119.17443982 .00000000 00000-0 00000-0 0 0013 2 00012 97.9497 178.9014 0004270 015.5590 198.2466 14.79780033 00004 --------------------------------------------------------------------- Satellite Uplink Downlink Beacon Mode Callsign CUTE1.7 1267.600 . . 9600bd GMSK JQ1YTC CUTE1.7 . 437.475 . 9600bd GMSK JQ1YTC CUTE1.7 . 437.475 . 1200bd AFSK JQ1YTC CUTE1.7 . . 437.275 CW SEEDS . 437.485 . FM,CW,Talk JQ1YGU DELFI-C3 . 145.870 . 1200bd BPSK DLFIC3 DELFI-C3 435.570-530 145.880-920 145.930 FM,CW COMPASS-1 . 437.405 . 1200bd AFSK COMPASS-1 . . 437.275 CW AAUSAT-II . 437.425 437.425 1200bd AFSK OZ2CUB AAUSAT-II . 437.425 437.425 9600bd FSK OZ2CUB CANX-2 . 437.478 . 32Kbd- VA3SFL CANX-2 . 2407.650 . 256Kbd GMSK VA3SFL --------------------------------------------------------------------- http://showcase.netins.net/web/wallio/CubeSat.htm http://www.dk3wn.info/calendar/satellit.php?language=german

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AMSAT Goes to the Races -- April 27
by Tom Clark, K3IO 22 Apr '08

22 Apr '08

This coming Sunday, April 27th, AMSAT will have its premiere at a major sports car race -- The Bosch Engineering 250 at the Virginia International Raceway (VIR) Grand-Am Rolex Sports Car Series; VIR is located near Danville, VA on the VA/NC border. Brad Jaeger (see http://www.bradjaeger.com) is the son of AMSAT member Jim Jaeger (K8RQ) and is piloting the bright yellow #77 Doran Racing Kodak Ford machine (which you can see at http://www.bradjaeger.com/?q=node/110 and at http://www.grand-am.com/rolex/drivers/driver.cfm?did=1110). K8RQ has arranged for AMSAT to display its colors on Brad's car on a "space available" basis. If you can make it to Danville for the weekend, the detailed schedule of events can be found at http://www.grand-am.com/assets/08VIROfficialSched2.pdf. But if you can't make it, the race will be carried on the cable SPEED channel from 12:00 to 15:00 EDT on Saturday, May 3rd. For more details about the Grand-Am Rolex racing series, see http://www.grand-am.com/rolex/ and http://www.virclub.com/latest-news/bosch-engineering-becomes-title-sponsor-…. 73 de Tom, K3IO

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Delfi-C3 telemetry decoding software test
by Wattage Perera 22 Apr '08

22 Apr '08

Hi to the BB, I was able to locally test the Delfi-C3 RASCAL software using the 5MB telemetry sound file from the Delfi-C3 website using my computer with the following method. Set your computer Sound Recording Device Properties using the following path. I am using Windows XP Home Edition. Control Panel ---- Sounds and Audio Devices ---- Sounds and Audio Devices Properties ---- Click on Audio tab ---- Click on Sound Recording Volume tab ---- Select Mono Mix on Sound Recorder Properties ---- Set the recording volume level to half way on the scale. Now make sure you have a check mark in the Sound Recorder select box. Download the 5MB WAV file onto your desktop from the following link in the Delfi-C3 website: http://www.delfic3.nl/index.php?option=com_content&task=view&id=23&Itemid=1… Open the computer Sound Recorder program ( All Programs ---- Accessories ---- Entertainment ---- Sound Recorder ) or use the Windows Media Player. Play back the telemetry sound file you downloaded. Open the Delfi-C3 RASCAL software. Now you should see the software screen decoding the playback telemetry sound file. You can set the audio level by adjusting the computer Sound Recorder Volume level setting. 73, Kumara Perera VE4WKP

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Re: Kenwood TH-F6a
by Clint Bradford 22 Apr '08

22 Apr '08

> .. is the TH-F6A my best choce for HT? for sats, ... or at least in > the top two?? Before I go down thr street to HRO and plunk down the > money... The TH-F6a is an excellent performer. It is NOT, however, a true full- duplex unit. It is a tri-band, dual receive unit. Full power output on all three bands (2M, 220, and 440). If you want/need dual-receive, it's a great unit. Minor drawback: Using its optional AA Alkaline pack, you're only operating at 1/2 W. Clint Bradford,K6LCS 909-241-7666

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