January 2010 - AMSAT-BB - mailman.amsat.org

Doppler effect
by Daniel F6CDZ 09 Jan '10

09 Jan '10

Hello to all. My little contribution for an explanation about the doppler effect.... 73, Daniel F6CDZ loc: JN39BE Doppler effect The Doppler effect is an immediate gap of the received frequency when the distance varies between the point of broadcast and the point of reception. The variation of frequency depends on the relative speed of link or on estrangement between the satellite and the station ground, of the angle of movement and the emitted frequency. The Doppler effect varies with the position of the satellite on its orbit, because the relative speed varies with this position. The frequency increases when the satellite approaches, it decreases when it goes away from the observer. The "simple" formula is : F real = F nom (1 + V/C) V = relative speed of the sat on Km/s C = light speed (300.000 Km/s) 1+ or 1- depending of the direction sat/operator (to the operator or from the operator) Mode NORmal and REVerse : ¾ NOR : if I increase 1 KHz on VHF, the UHF increases also of 3 KHz => total gap (+1 + +3) = + 4 KHz ¾ INV(REV) : if I increase 1 KHz on VHF, the UHF decreases of 3 KHz => total gap (+1 - 3) = - 2 KHz

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what did I hear?
by francesco messineo 09 Jan '10

09 Jan '10

Hi all, I'm just listening for a SO-67 pass and the satellite seems not operational at this time (8:40 UTC) but around 435.355 MHz +/- doppler I started hearing a kind of cw telemetry in short intervals. They are 6 letter "packets" or so, like ISUN44. I didn't copy other packets as I was busy trying to identify the satellite with the tracking program, but it must not be one of my "favourite" ones. What was I hearing? Thanks Frank IZ8DWF (currently in JM49MG).

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Re: AO-7 QSO 7694 Km
by Bob- W7LRD 09 Jan '10

09 Jan '10

Hello Piraja and all Congratulations, a great feat!.. I also am looking forward to a edge to edge QSO with PA1TNO in JO22li from CN87wk. If ever successful it would be 7837km. The allotted time is around 25 seconds I think though to be successful I might have to increase the height of my satellite array to 50 feet. This is divorce height, so efforts will be made at the 18 foot level. 73 Bob W7LRD Seattle. Wa. CN87wk ----- Original Message ----- From: "ps8rf Piraja" <ps8rf(a)hotmail.com> To: amsat-bb(a)amsat.org Sent: Friday, January 8, 2010 3:14:07 PM GMT -08:00 US/Canada Pacific Subject: [amsat-bb] AO-7 QSO 7694 Km Hello all, I posted a short video with the contact maintained today with Andre, ZS2BK via AO-7 in mode B ( Orbit 60848 - 19:47 UTC - 01/08/10 ). We keep the QSO with a small window that the AO-7 has provided us. The window was only about 34 sec, this time interval we could not match any commit error. The distance between the two stations is 4085 miles or 7669 Km. Andre wrote via email: " "My Doppler calc was also gratefully spot on. For example I calculated that I should call so that my downlink is on 145.944.2 mhz I worked out that our Doppler difference would be 3.8 khz and amazing that was spot-on. There is really no time to tune !" Andre is right the time was too little for adjustments. Taking also into account that I manually worked the rotor and control of my rig. See the sound/video in youtube: http://www.youtube.com/watch?v=zNFmHERisWQ I hope you enjoy it 73, Pirajá, PS8RF _________________________________________________________________ O Novo Windows 7 funciona do jeito que você quer. Clique aqui para conhecer! http://www.microsoft.com/brasil/windows7/default.html?WT.mc_id=1539 _______________________________________________ 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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Re: probably simple
by Edward Cole 09 Jan '10

09 Jan '10

The rate of change of Doppler is a sinusoidal function, so... Think of a sine wave: the change in amplitude is highest close to the zero crossing and smallest around the plus and minus maximums. 73, Ed - KL7UW At 09:28 AM 1/8/2010, Mark L. Hammond wrote: >I think part of the subject that confuses most of us (me included!) is >that while at TCA the offset is 0, the RATE of change on either side >of TCA is higher than at AOS or LOS. So, the actual frequency >offset is BIGGEST at LOS and AOS, but the rate of change is slow (it >doesnt' change much). It's easier to tune. At TCA you should hear >the satellite at the "actual" frequency, but not for long because the >change in frequency is fastest right before and right after...you tune >like crazy to keep up. > >Maybe that will make sense to somebody...but I won't promise :) > >Also---don't forget---a 10kHz offset at 2M is 30kHz at 70cm (and one >is increasing in freq while the other is decreasing...) > >Use SatPC32 and you just about forget about having to do anything, and >watch it happen--good chance to see what is really going on. > > >73, > >Mark N8MH > >On Fri, Jan 8, 2010 at 1:11 PM, Pete Rowe <ptrowe(a)yahoo.com> wrote: > > Hi Greg > > I'm confused. It seems to me that the place when Doppler is zero > is when the satellite is about half way through the pass. This is > when the Doppler goes from positive (coming at me) to negative > (going away from me). It seems like this place would be the time of > closest approach (TCA) and not way out on the horizon when I see > maximum Doppler. > > What am I missing? > > > > 73, > > Pete > > WA6WOA > > > > --- On Thu, 1/7/10, Greg D. <ko6th_greg(a)hotmail.com> wrote: > > > > From: Greg D. <ko6th_greg(a)hotmail.com> > > Subject: [amsat-bb] Re: probably simple > > To: glasbrenner(a)mindspring.com > > Cc: amsat-bb(a)amsat.org > > Date: Thursday, January 7, 2010, 7:34 PM > > > > > > Hi Drew, > > > > SatPC32 is probably an excellent program (I'm on Linux here, so > can't use it), and if you've got the automation available, that's > certainly the best way to go. And, by definition, the lower the > elevation, the farther away the satellite is, so your DX contacts > are going to be at the edges of the pass. > > > > But any pass where you are really stretching the footprint is > going to be a low elevation pass. The more you stretch, the lower > the pass. In the limit, I think Bob's ultimate pass has a peak at > .001-degrees for both stations. If you're doing that, then you're > at TCA, and zero doppler. > > > > That's all I meant to convey, > > > > Greg KO6TH > > > > > >> Date: Thu, 7 Jan 2010 05:53:13 -0500 > >> From: glasbrenner(a)mindspring.com > >> To: ko6th_greg(a)hotmail.com > >> CC: w7lrd(a)comcast.net; amsat-bb(a)amsat.org > >> Subject: Re: [amsat-bb] Re: probably simple > >> > >> Greg D. wrote: > >> > Hi Bob, > >> > > >> > Whatever the satellite, if you're trying to stretch the > footprint, your sked is always going to be at the peak of > elevation, for that fleeting moment when the satellite is a few > degrees above the horizon. That means that you're always going to > be at zero doppler shift, and the math will always be the > same. Find yourself once at TCA on any pass, and lock them > in. The numbers will be the same for your sked. > >> > > >> > Good luck, > >> > > >> > Greg KO6TH > >> > > >> > > >> I wouldn't agree with that statement at all. Most of my long haul > >> contacts on AO-7, FO-20 and 29, and now HO-68, are right after AOS or > >> just before LOS, certainly not at TCA. Use my recent QSOs on HO-68 with > >> Argentina as an example. Even when I work Europe on AO-7 it is at the > >> beginning or end of a pass...not the middle. > >> > >> Bob, SatPC32 will show you the frequency with Doppler shift, and the > >> Doppler shift. A little subtraction or addition and you have > what you want. > >> > >> 73, Drew KO4MA > > > >_______________________________________________ >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 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubususa(a)hotmail.com ======================================

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FW: AO-7 QSO 7694 Km
by ps8rf Piraja 08 Jan '10

08 Jan '10

Sorry, the Correct distance the is 7694 Km 73 Piraja, PS8RF From: ps8rf(a)hotmail.com To: amsat-bb(a)amsat.org Subject: AO-7 QSO 7694 Km Date: Sat, 9 Jan 2010 02:14:07 +0300 Hello all, I posted a short video with the contact maintained today with Andre, ZS2BK via AO-7 in mode B ( Orbit 60848 - 19:47 UTC - 01/08/10 ). We keep the QSO with a small window that the AO-7 has provided us. The window was only about 34 sec, this time interval we could not match any commit error. The distance between the two stations is 4085 miles or 7669 Km. Andre wrote via email: " "My Doppler calc was also gratefully spot on. For example I calculated that I should call so that my downlink is on 145.944.2 mhz I worked out that our Doppler difference would be 3.8 khz and amazing that was spot-on. There is really no time to tune !" Andre is right the time was too little for adjustments. Taking also into account that I manually worked the rotor and control of my rig. See the sound/video in youtube: http://www.youtube.com/watch?v=zNFmHERisWQ I hope you enjoy it 73, Pirajá, PS8RF Quer ver seus e-mails de todas as contas num lugar só? Junte todas elas no Hotmail. _________________________________________________________________ Deixe seu computador compatível com a sua vida. Clique para conhecer o Windows 7! http://www.microsoft.com/brasil/windows7/default.html?WT.mc_id=1539

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HO68 - FM mode, QSO VA3-SP7
by Mateusz 08 Jan '10

08 Jan '10

Record is edited to save ears from noise and it is short: http://www.enduro.idl.pl/audio_sat/va3fm_ho68_08012010_2240UTC.mp3 There were a longer pauses between transmisions caused by interferences. VA3FM - thanks for QSO. Matt SQ7DQX

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Re: FO-29 Schedule
by Mineo Wakita 08 Jan '10

08 Jan '10

FO-29 should come out of the eclipse soon. JARL still are making an effort hard the examination use. A operating schedule will be announced soon. JE9PEL, Mineo Wakita

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7 Messages to H ope-1 BBS in one pass, with attached files photos (1ST TIME)
by Nader Omer 08 Jan '10

08 Jan '10

I succceded to upload 7 messages to BBS on board hope-1 oscar satellite in one pass! Orbit # 323 time 18:42- 19:02 date 8-01-2010 locator KK65GP Messages to dk3wn 2 messages one with attached photo hb9ska message to all message to ba1du message to w0sl message to je9pel see the photos for more http://picasaweb.google.com/Nader.st2nh/7MessagesToHope1BbsInOnePassWithAtt… PhotoFile1stTime# 73 de Nader , st2nh www.st2nh.com

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Re: Galileo Contract Awarded
by gw1fky＠aol.com 08 Jan '10

08 Jan '10

Hi all, Yes very pleased to hear the news and was about to post the information to the BBs. Many congratulations to Sir Martin Sweeting and his team at SSTL - a very just reward for all of the hard work and efforts by all involved. The news is also published in full on the SSTL web pages. Martin of course for anyone not aware is also Chairman of Amsat - UK and plays a key role in his support and contributions to the roles of amateur satellites and projects. Best wishes and continued " Good Luck " Ken Eaton GW1FKy Amsat - UK Amsat NA

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Re: Ham Radio University
by Clint Bradford 08 Jan '10

08 Jan '10

>> ... presentation and demonstration ... 01/10/10 ... hamradiouniversity.org ... OUTSTANDING, PETER! It has been great sending email messages back and forth with you last year. Then actually speaking with you on your VOIP net last week. NEXT: Actually meeting you! You'll do great at the hamvention. Just be yourself - you've got the right attitude and enthusiasm. Have a pad and paper handy for any Q&A inquiries that you cannot immediately answer for your audience: They'll appreciate the fact that you promise to get 'em the answers via email ASAP. Clint, K6LCS 909-241-7666

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