February 2007 - AMSAT-BB - mailman.amsat.org

Re: Yes, DStar can work on LEO,
by Andrew Glasbrenner 27 Feb '07

27 Feb '07

Gentlemen, Please do not use FM on any of the transponder satellites, whether D-Star or plain FM. FM of any kind is expressly unwelcome on AO-7 especially. If you would like to set up a test of D-Star via AO-51, please organize the effort and send a request to schedule it to ao51-modes(a)amsat.org or to myself directly and we will accommodate the test on a FM satellite, where FM belongs. I think it'd be an interesting experiment. 73, Drew KO4MA AMSAT-NA VP Ops ----- Original Message ----- From: "MM" <ka1rrw(a)yahoo.com> To: "Dave hartzell" <hartzell(a)gmail.com>; "Amsat BB" <amsat-bb(a)amsat.org> Sent: Monday, February 26, 2007 4:18 PM Subject: [amsat-bb] Re: Yes, DStar can work on LEO, In my first memo about Digital Audio on Satellites I did not have time to go over a few other outstanding issues, such as Inverting Transponders and Doppler on the 440 band. Will DV work on Inverting Transponders? I do not know. My guess is that Non-inverting would work better, but that's just a guess. Let's try it and find out. Doppler on 440. The Doppler on 440 is plus and minus 10 kHz. That is too much for the ID-800 and similar radios running digital audio. Normal FM 5k deviation voice can work find at 3 kHz frequency error and is even usable with noise up to 6 kHz of frequency error. Digital Voice would work best on 10 meter / 2 meter satellites, with non-inverting transponders. Maybe AO-7 could work. The other satellite VUSat-OSCAR 52 is inverting. Future Radios: Wish List Most mobile radios made today are designed for channel steps starting at 5 kHz, 6.25, etc. It would be desirable if manufactures would design their rigs for smaller channels steps to allow us a little more flexibility in using them for FM satellites. It would not add much cost to a typical FM mobile rig to allow 1.0 kHz and 2.5 kHz channel steps. For FM satellites you do not need to be exactly on frequency. You just need to be in the ball park (plus and minus 2.5 kHz works). Miles --- Dave hartzell <hartzell(a)gmail.com> wrote: > Will this still work on an inverting transponder? > > On 2/26/07, MM <ka1rrw(a)yahoo.com> wrote: > > > > The Icom IC-800 will work with some Doppler Error > in > > Digital voice mode. > > I have been testing the IC-800 specifically to see > how > > well it would work in theory with a 2-meter signal > > from a simulated LEO Orbit, such as ISS at 240 > miles > > altitude. > > The results have been very promising on Earth. > > > > The IC-800 will decode good Digital voice, with a > > frequency error of > 2.5 kHz. > > And this was at an indicated signal level of S1 on > the > > radios S-Meter. > > At higher S-Signal levels the amount of frequency > > error the IC-800 can tolerate in digital voice > mode is > > higher. > > > > I setup a pair of IC-800 20 miles away. Then by > using > > a combination of 5k channels on one radio and > 6.25k > > channels on the other radio, i was able to > simulate 2, > > 2.5k and 3k channel doppler errors. A beam > antenna > > was used to Lower the indicated Signals levels > until > > audio quality droped. > > > > The lower the altitude the higher the Doppler > > (Frequency dependant too). The Doppler from ISS > is > > approximately Plus and Minus 3.3 kHz. This means > that > > If a LEO satellite is approaching on 2-meters, the > > frequency you will see on your radio will be up to > 3.3 > > kHz higher for the first minute, then will quickly > > drop to zero Doppler for a few seconds at the 5 > minute > > mark (assuming a 10 minute pass). > > > > So, in theory, if the Doppler on a transponder > based > > satellite is less than 3 kHz and you have signals > > stronger than 1 S-Unit, it should be possible for > > 2-way Leo satellite via digital voice. Anyone > else > > have an IC-800 and want to test? > > > > Miles WF1F > > > > www.marexmg.org > > > > ka1rrw(a)yahoo.com > > > > > > > > > > > > > ____________________________________________________________________________________ > > Now that's room service! Choose from over 150,000 > hotels > > in 45,000 destinations on Yahoo! Travel to find > your fit. > > http://farechase.yahoo.com/promo-generic-14795097 > > _______________________________________________ > > Sent via AMSAT-BB(a)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 > > > > > -- > "It is far better to grasp the Universe as it really > is than to > persist in delusion, however satisfying and > reassuring." - Carl Sagan. > _______________________________________________ > Sent via AMSAT-BB(a)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 > ____________________________________________________________________________________ We won't tell. Get more on shows you hate to love (and love to hate): Yahoo! TV's Guilty Pleasures list. http://tv.yahoo.com/collections/265 _______________________________________________ Sent via AMSAT-BB(a)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

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Ofcom consultation on candidate bands under consideration at WRC-07 for IMT
by Trevor 27 Feb '07

27 Feb '07

Ofcom consultation on candidate bands under consideration at WRC-07 for IMT http://www.ofcom.org.uk/consult/condocs/wrc07/ Some of the segments mentioned overlap with existing Amateur allocations. 2300-2400 MHz, 3400 to 3600 MHz and just below 70cm 410-430 MHz. Anyone can respond to Ofcom consultations, they are NOT resistriced to British Isles or EU citizens. The deadline for responses is 30 March. 73 Trevor M5AKA ---- Ofcom consultation on candidate bands under consideration at WRC-07 for IMT Date: Tue, 27 Feb 2007 10:02:34 -0000 From: "Updates" <Updates(a)ofcom.org.uk> Ofcom has today published a consultation on spectrum requirements for the future development of advanced mobile wireless communications systems (or IMT) which are under consideration at the 2007 World Radio Conference of the International Telecommunications Union (ITU). The deadline for responses is 30 March. Further information can be found at: http://www.ofcom.org.uk/consult/condocs/wrc07/ ---- ___________________________________________________________ New Yahoo! Mail is the ultimate force in competitive emailing. Find out more at the Yahoo! Mail Championships. Plus: play games and win prizes. http://uk.rd.yahoo.com/evt=44106/*http://mail.yahoo.net/uk

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Re: Can D-Star work on VO-52?
by Edward Cole 27 Feb '07

27 Feb '07

GMSK: <from wikipedia> Gaussian minimum shift keying or GMSK is a kind of continuous phase <http://en.wikipedia.org/wiki//wiki/Frequency-shift_keying>frequency-shift keying. The baseband <http://en.wikipedia.org/wiki//wiki/Modulation>modulation is generated by starting with a <http://en.wikipedia.org/wiki//wiki/Bitstream>bitstream 0/1 and a bit-clock giving a <http://en.wikipedia.org/wiki//w/index.php?title=Timeslice&action=edit>timeslice for each <http://en.wikipedia.org/wiki//wiki/Bit>bit. This is the type of modulation used in <http://en.wikipedia.org/wiki//wiki/Global_System_for_Mobile_Communications>Global System for Mobile Communications (GSM) - although that system includes <http://en.wikipedia.org/wiki//wiki/Differential_encoding>differential encoding of the bitstream, which makes the overall modulation behave like a kind of continuous phase <http://en.wikipedia.org/wiki//wiki/Binary_Phase_Shift_Keying>Binary Phase Shift Keying with constant <http://en.wikipedia.org/wiki//wiki/Envelope_detector>envelope. The baseband <http://en.wikipedia.org/wiki//wiki/Signal_%28information_theory%29>signal is generated by first transforming the zero/one encoded bits into -1/+1 encoded bits. This -1/+1 signal is then <http://en.wikipedia.org/wiki//wiki/Electronic_filter>filtered in such a way that the "boxcar" shaped +1/-1 <http://en.wikipedia.org/wiki//wiki/Pulse>pulses are transformed into <http://en.wikipedia.org/wiki//wiki/Normal_distribution>Gaussian-shaped signals. The baseband signal is then modulated using <http://en.wikipedia.org/wiki//wiki/Frequency_modulation>frequency modulation, producing a complete GMSK signal. If the Gaussian shapes do not overlap, then the modulation form is called 1-GMSK. If the slots overlap 50% (½), the modulation is called 2-GMSK, and so on. The more the bits overlap, the more significant <http://en.wikipedia.org/wiki//wiki/Intersymbol_interference>intersymbol interference (ISI) from adjacent bits will be, and for 4-GMSK and up, the ISI seen at any particular point in time is stronger than the signal from the bit currently being decoded. By looking at greater parts of the signal using advanced decoder techniques (including <http://en.wikipedia.org/wiki//wiki/Viterbi_algorithm>Viterbi algorithm decoders), high density codings can be decoded efficiently. Currently the highest density coding being used is 5-GMSK. GMSK has high <http://en.wikipedia.org/wiki//wiki/Spectral_efficiency>spectral efficiency, but it needs higher <http://en.wikipedia.org/wiki//wiki/Electrical_power>power level than for instance <http://en.wikipedia.org/wiki//wiki/Quadrature_phase-shift_keying>Quadrature phase-shift keying (<http://en.wikipedia.org/wiki//wiki/QPSK>QPSK) to reliably <http://en.wikipedia.org/wiki//wiki/Communicate>communicate the same amount of <http://en.wikipedia.org/wiki//wiki/Data>data. <Don't ask me what it means> 73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa(a)hotmail.com ======================================

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Re: Can D-Star work on VO-52?,
by William Leijenaar 27 Feb '07

27 Feb '07

Hi AMSATs, The HAMSAT (Vo-52) has linear transponders, what means that what is comming in also goes out. The only problem might be that the output spectrum is inverted in frequency. For FM this has no hearable effect, and even the 9k6 packet has no problem with it. On SSB the inversion results in modulation change from e.g USB to LSB. For D-Star I don't know if it can handle an inverted RF signal. I have been looking for some info but the whole D-star system is not to much transparant. The claim that it can be used with homebrew equipment, but didn't seen any kits yet. I think it is all commercial monopoly minded. Only hams with the $$$$ will be able to buy it, but have actually no idea what is going oun and comming out of their "black-box". When we want a digital system I would go for something like CDMA. This system seems to be more ham friendly and can be implemented in a homebrew way. As example look at this link: http://www.tapr.org/ss_g1pvz.html Great experiment... this is real ham, even if it is not the FM or SSB we are used to do... Ham are to explore RF technology, not to only buy and talk... Then you can better use a phone :o) 73 de William --- ____________________________________________________________________________________ Never miss an email again! Yahoo! Toolbar alerts you the instant new Mail arrives. http://tools.search.yahoo.com/toolbar/features/mail/

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Re: Thermocouple power
by don 27 Feb '07

27 Feb '07

Its certainly possible, but the only system I have any knowledge of is by using the heat produced by radioactive decay. This was /is used by various military satellites in the 1980's at least. Maybe it still is. Try this url for a bit of info. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator Don. ZL1THO

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Re: Thermocouple power
by Tony Langdon 27 Feb '07

27 Feb '07

Oops, forgot to post to the list... At 10:46 AM 2/27/2007, you wrote: >Last week there was an interesting debate about raising the altitude of a >satellite by using magnertic fields. > >Carrying on the wacky ideas theme, I've been looking at producing power by >using thermocouples and not solar cells. This certainly does work, because the principle is used in the RTGs that power the Pioneer 11/10 probes, Voyagers, Galileo, New Horizons and Cassini. In this case, the heat is provided by radioactive decay of plutonium rather than solar energy. In the case of these probes, RTGs are used because solar power is not a practical alternative beyond Jupiter, and no other power source is capable of lasting decades while generating several hundred Watts in deep space. >But.........how much power can you draw from it ?? Depends how much heat energy you can put into it from the Sun. That I don't know. 73 de VK3JED http://vkradio.com

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ARRL Field Day rule change request successful.
by Andrew Glasbrenner 27 Feb '07

27 Feb '07

It looks like the ARRL agreed with my request to modify their Field Day rules to mirror our own on FM satellite QSOs. >From http://www.arrl.org/contests/rules/2007/fd.html 7.3.7. Satellite QSO: 100 bonus points for successfully completing at least one QSO via an amateur radio satellite during the Field Day period. "General Rules for All ARRL Contests" (Rule 3.7.2.), (the no-repeater QSO stipulation) is waived for satellite QSOs. Groups are allowed one dedicated satellite transmitter station without increasing their entry category. Satellite QSOs also count for regular QSO credit. Show them listed separately on the summary sheet as a separate "band." You do not receive an additional bonus for contacting different satellites, though the additional QSOs may be counted for QSO credit unless prohibited under Rule 7.3.7.1. The QSO must be Earth-Satellite-Earth in nature. Available to Classes A, B, and F. 7.3.7.1 Stations are limited to one (1) completed QSO on any single channel FM satellite. Thank you to the ARRL and the Contest Advisory Committee for your cooperation, and see you on the satellites on Field Day. 73, Drew KO4MA AMSAT-NA VP Ops

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Re: Yes, DStar can work on LEO,
by Jim Wright 27 Feb '07

27 Feb '07

If the high speed data modes will work, then digital voice should also. The DV may not sound like the telephone quality we are used to hearing, but the only difference would be the D/A conversion that puts the ones and zeros out the speaker instead of on the screen or paper. You may have to wait for the buffer to fill and output the speach as often happens on slow VoIP connections. We are used to that when someone is using vox and AAAahhhhhhhhhhhhhs alot to keep the vox from reacting. 38k4 may be too slow to avoid this, but how long ago did we just have 300 baud data or 45 baud TTY. QRM and QRN will be great obstacles to overcome, not to mention the acquire LOCK time before roundtables become commonplace. 73, Jim MM wrote: >In my first memo about Digital Audio on Satellites I >did not have time to go over a few other outstanding >issues, such as Inverting Transponders and Doppler on >the 440 band. > >Will DV work on Inverting Transponders? >I do not know. My guess is that Non-inverting would >work better, but that's just a guess. >Let's try it and find out. > >Doppler on 440. >The Doppler on 440 is plus and minus 10 kHz. That is >too much for the ID-800 and similar radios running >digital audio. Normal FM 5k deviation voice can work >find at 3 kHz frequency error and is even usable with >noise up to 6 kHz of frequency error. Digital Voice >would work best on 10 meter / 2 meter satellites, with >non-inverting transponders. Maybe AO-7 could work. >The other satellite VUSat-OSCAR 52 is inverting. > >Future Radios: Wish List >Most mobile radios made today are designed for channel >steps starting at 5 kHz, 6.25, etc. >It would be desirable if manufactures would design >their rigs for smaller channels steps to allow us a >little more flexibility in using them for FM >satellites. It would not add much cost to a typical >FM mobile rig to allow 1.0 kHz and 2.5 kHz channel >steps. For FM satellites you do not need to be >exactly on frequency. You just need to be in the ball >park (plus and minus 2.5 kHz works). > >Miles >--- Dave hartzell <hartzell(a)gmail.com> wrote: > > > >>Will this still work on an inverting transponder? >> >>On 2/26/07, MM <ka1rrw(a)yahoo.com> wrote: >> >> >>>The Icom IC-800 will work with some Doppler Error >>> >>> >>in >> >> >>>Digital voice mode. >>>I have been testing the IC-800 specifically to see >>> >>> >>how >> >> >>>well it would work in theory with a 2-meter signal >>>from a simulated LEO Orbit, such as ISS at 240 >>> >>> >>miles >> >> >>>altitude. >>>The results have been very promising on Earth. >>> >>>The IC-800 will decode good Digital voice, with a >>>frequency error of > 2.5 kHz. >>>And this was at an indicated signal level of S1 on >>> >>> >>the >> >> >>>radios S-Meter. >>>At higher S-Signal levels the amount of frequency >>>error the IC-800 can tolerate in digital voice >>> >>> >>mode is >> >> >>>higher. >>> >>>I setup a pair of IC-800 20 miles away. Then by >>> >>> >>using >> >> >>>a combination of 5k channels on one radio and >>> >>> >>6.25k >> >> >>>channels on the other radio, i was able to >>> >>> >>simulate 2, >> >> >>>2.5k and 3k channel doppler errors. A beam >>> >>> >>antenna >> >> >>>was used to Lower the indicated Signals levels >>> >>> >>until >> >> >>>audio quality droped. >>> >>>The lower the altitude the higher the Doppler >>>(Frequency dependant too). The Doppler from ISS >>> >>> >>is >> >> >>>approximately Plus and Minus 3.3 kHz. This means >>> >>> >>that >> >> >>>If a LEO satellite is approaching on 2-meters, the >>>frequency you will see on your radio will be up to >>> >>> >>3.3 >> >> >>>kHz higher for the first minute, then will quickly >>>drop to zero Doppler for a few seconds at the 5 >>> >>> >>minute >> >> >>>mark (assuming a 10 minute pass). >>> >>>So, in theory, if the Doppler on a transponder >>> >>> >>based >> >> >>>satellite is less than 3 kHz and you have signals >>>stronger than 1 S-Unit, it should be possible for >>>2-way Leo satellite via digital voice. Anyone >>> >>> >>else >> >> >>>have an IC-800 and want to test? >>> >>>Miles WF1F >>> >>>www.marexmg.org >>> >>>ka1rrw(a)yahoo.com >>> >>> >>> >>> >>> >>> >>> >>> >____________________________________________________________________________________ > > >>>Now that's room service! Choose from over 150,000 >>> >>> >>hotels >> >> >>>in 45,000 destinations on Yahoo! Travel to find >>> >>> >>your fit. >> >> >>>http://farechase.yahoo.com/promo-generic-14795097 >>>_______________________________________________ >>>Sent via AMSAT-BB(a)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 >> >> >>-- >>"It is far better to grasp the Universe as it really >>is than to >>persist in delusion, however satisfying and >>reassuring." - Carl Sagan. >>_______________________________________________ >>Sent via AMSAT-BB(a)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 >> >> >> > > > > >____________________________________________________________________________________ >We won't tell. Get more on shows you hate to love >(and love to hate): Yahoo! TV's Guilty Pleasures list. >http://tv.yahoo.com/collections/265 >_______________________________________________ >Sent via AMSAT-BB(a)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 > > > >

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FS: Kenwood TS790A satellite rig
by John Geiger 27 Feb '07

27 Feb '07

I have a Kenwood TS790A 2m/70cm all mode satellite rig for sale or trade. This is a great all mode radio, but I am looking for something with 6 meters on it. It comes with the hand mic, power cord, manual and original double boxes. It is in good shape, but not mint. There are some scratches on the top, but the face looks really good. This was Kenwood's top of the line VHF rig, and still is considered one of the best VHF/UHF weak signal/contest/satellite rigs. You can add an optional 23cm unit if you like (not included) and it has the full duplex satellite tracking mode. Go read the eham.net reviews or the QST product review to see what a great rig this is. It does 50 watts on 2m and 40 watts on 70cm, and has the tone encoder/decoder installed. I would trade for a HF/6m rig like the Kenwood TS690/570, or Icom 756/746, or make a trade offer. I am also open to cash offers for it. I would throw in some cash with it towards a Kenwood TS2000. Don't miss out on this Kenwood classic. 73s John W5TD ____________________________________________________________________________________ Never miss an email again! Yahoo! Toolbar alerts you the instant new Mail arrives. http://tools.search.yahoo.com/toolbar/features/mail/

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Re: Here are 30 Helpful steps for new Hams now that CW is gone.
by Margaret Leber 27 Feb '07

27 Feb '07

On 2/26/07, Vince Fiscus, KB7ADL <vlfiscus(a)mcn.net> wrote: > The 30 Steps below will help all new co-code HF'ers, it will also help you to > find others just like yourself... Funny, one would have thought all these inanities would have been just as lame while a CW exam was still required for HF access, especially since they all seem to apply to FM repeater usage. Helpful Steps for Old Hams: Find some old humorous list of annoying habits of noobs on FM repeaters, and repost it implying that all these gaucheries are somehow caused by the fact that there's now no practical test of CW skill to get legal access to HF. Ignore the fact that there's never been any practical test of skill with SSB, AM, Packet, SSTV, ATV, PSK31, RTTY, AMTOR, WSJT, EME or Feld Hell, all of which are also obvious hallmarks of superior intelligence, character, ethics and high operating standards. Extra points are awarded for equating all new hams with CBers, since that worked so well last time around. There's an additional bonus for annoucing that "the end of CW tests for licensing" is the same as "the end of anybody ever using Morse Code on the amateur bands", thus making it clear to all the newcomers that the only reason anybody ever used CW was because they were forced to. You won't have any trouble finding others just like yourself....just turn off your notch filter so you can clearly hear the sound of whining... -- 73 de Maggie K3XS Editor, Phil-Mont Mobile Radio Club Blurb - http://www.phil-mont.org Elecraft K2 #1641 -- AOPA 925383 -- ARRL 39280

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