May 2013 - AMSAT-BB - mailman.amsat.org

Rising Price of Flights to the ISS
by M5AKA 02 May '13

02 May '13

New price for flights to the ISS will be $71 million per person from 2017. Current price paid by NASA is $55.8 million per person and that is due to rise to $62.75 million next year, a year or so ago they were paying $51 million, see http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_05_01_2013_p01… 73 Trevor M5AKA ----

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Re: [Forum] S-Band Downlink auf HEO/GEO noch sinnvoll?
by i8cvs 02 May '13

02 May '13

Hi Peter, DB2OS I am still using a 120 cm (4 foot) parabolic dish for 2400 MHz and I noted that when the elevation is about 10 degres above the horizon here in the bay of Napoli there are not heavy interference from WiFi tuning between 2400 to 2402 MHz so that actually the old OSCAR-40 (P3-D) S band is still usable here. We need not a new S band but a new P3E satellite. Best 73" de i8CVS Domenico > Hi there, > > many of us will certainly remember the Mode S downlink of AMSAT > OSCAR-40 (P3-D) remember. > > After initial skepticism, especially after the 2m transmitter > failed, Mode-S was indeed an amazing encouragement and was > bad out of "Easy Mode". > I myself can not in experiments with different antennas and > Feeds remember, through the bathroom window in the direction of AO-40 ... > The signals were glaskar and the tape clean, even weak stations > were easy to understand .. > > 10 years later, each more than a 2.4 GHz WiFi wireless router, > Laptop and smartphone in the house, the neighbors and office buildings > around a > around all ... > In the country there are also many "citizen networks" with Wi-Fi to all > Villages to provide them with inexpensive internet ... > > Probably the noise level is now very high, and even > when working with parabolic antennas to heaven, you will be on the > Sidelobes surely still a mess from all of WLANs > Receive directions ... remains of the actual desired > Useful signal probably little left .. > > Under these conditions would have an S-band downlink like you would with > AO-40 > still have a chance? > > Has anyone had any experience in this regard and perhaps collected with > a connected spectral antennas in all the times > Rotated directions? > > Under https://www.facebook.com/amsat.deutschland there is a small > To vote .. > > > 73s Peter DB2OS > > > ----- Original Message ----- > From: "Peter Guelzow" <peter.guelzow(a)kourou.de> > To: "AMSAT - Forum" <Forum(a)amsat-dl.org> > Sent: Wednesday, May 01, 2013 8:33 PM > Subject: [Forum] S-Band Downlink auf HEO/GEO noch sinnvoll? > > > Hallo zusammen, > > viele von uns werden sich bestimmt noch an die Mode-S Downlink von AMSAT > OSCAR-40 (P3-D) erinnern. > > Nach anfänglicher Skepsis, insbesondere nachdem der 2m-Sender > ausgefallen war, fand Mode-S ja einen erstaunlichen Zuspruch und war > schlecht hin der "Easy Mode". > Ich selbst kann mich noch an Versuche mit verschiedenen Antennen und > Feeds erinnern, durch das Badezimmer-Fenster in Richtung AO-40... > Die Signale waren glaskar und das Band sauber, selbst schwache Stationen > waren problemlos zu verstehen.. > > 10 Jahre später hat jeder mehr als einen 2,4 GHz WiFi WLAN-Router, > Laptop und Smartphone im Hause, die Nachbarn und Bürogebäude um einen > herum auch alle... > Auf dem Lande gibt es ja auch viele "Bürgernetze" mit WLAN um ganze > Dörfer preiswert mit Internet zu versorgen... > > Wahrscheinlich ist der Grundrauschpegel inzwischen sehr hoch und selbst > wenn man mit Parabolantennen gegen Himmel arbeitet, wird man über die > Nebenzipfel sicher noch ein Durcheinander von WLAN's aus allen > Richtungen empfangen... dann bleibt von dem eigentlich gewünschten > Nutzsignal wohl wenig übrig.. > > Hätte unter diesen Bedingungen eine S-Band Downlink wie eben bei AO-40 > noch eine Chance? > > Hat jemand diesbezüglich schon Erfahrungen gesammelt und vielleicht mit > einem angeschlossenen Spektralanalyse mal die Antennen in alle > Richtungen gedreht? > > Unter https://www.facebook.com/amsat.deutschland gibt es eine kleine > Abstimmung dazu.. > > > 73s Peter DB2OS

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VHF Amps (Smaller) for Sale
by Les Rayburn 02 May '13

02 May '13

Cleaning out extra & backup items from the shack in an attempt to stave off bankruptcy and the poor-house while paying for my daughter's wedding. :-) Selling off a few small amplifiers that may be of use to other VHF Weak Signal fans. All amps are in good working condition. Cosmetically, they are "USED", meaning that they have the usual scratches, etc. No major dents, paint loss, etc. Perfectly acceptable and XYL approved , but not mint from the factory. If you're not happy we'll make it right. Relax, it's just a hobby. Prefer Paypal payment or USPS Money Order. Shipping via UPS Ground is included in the price. TE Systems Model 0510G 50-54 MHz (6 Meter) Linear Amplifier (SSB/CW/FM) Serial #A7173 10 Watts input-150 Watts Output. The amp is rated for 170 Watts Output, but I never drove it that hard. This amp was modified by TE Systems to provide an RCA rear panel input jack for PTT keying. You simply connect a footswitch, handheld PTT, or amp keying line to this jack, close to ground, and the amp keys. Saves wear and tear on the relay. $225 TE Systems Model 1412G 144-148 MHz (2 Meter) Linear Amplifier (SSB/CW/FM) Serial #38482 10 Watts input-190 Watts Output This amp includes heavy duty power connector with Anderson Power-Poles. TE Systems plug including RCA female PTT keying circuit. Simply attach a footswitch, handswitch or amp keying line to this connector, close to ground and amp keys. Saves wear and tear on the relay. $250 Mirage A1015 50-52 MHz Linear Amplifier (SSB/CW/FM) Serial #93-234 10 Watts Input-150 Watts Output This amp includes heavy duty power connector with Anderson Power-Poles. This is the non-G model, with the older brown face. Does not include RF sensing switching, so you HAVE to use the RCA plug on the rear to key the amp using a footswitch, handswitch, or amp key line. But then again, who does weak signal work and doesn't do that anyway. Great workhorse amp at a good price. Used mine with a Flex 1500. 5 watts input pushes about 80 watts output. $225 Advice to OM's with daughters. Start saving now!!! :-) -- -- 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

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Fermi Avoids Near Miss In Orbit
by B J 02 May '13

02 May '13

http://www.nasa.gov/mission_pages/GLAST/news/bullet-dodge.html 73s Bernhard VA6BMJ @ DO33FL

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Re: Path to HEO
by Patrick Strasser 02 May '13

02 May '13

schrieb Ken Ernandes on 2013-04-30 09:49: > I note the disclaimer at the bottom, so I'll help with the incorrect assumptions. > > 1. g = 9.81 m/sec only applies to one Earth radius (i.e., the Earth's surface). Gravitational acceleration drops of as an inverse square of the radius. > 2. GEO altitude is close to 36000 km, but GEO radius is approximately 42164 km (you must add the Earth's radius to altitude to get orbital radius) Gotcha! > Gravity can be simplified by using a constant MU = 398600.4418 km^3/sec^2 > > For any radius you can compute g by: > > g = MU / r^2 > > But make sure you use radius and not altitude. Mean Earth radius at mid-latitudes is approximately 6371 km and is 6378 at the equator. > > The speed (v) for an elliptical orbit can be computed from the current radius (r) and semi-major axis (a): > > v = sqrt(MU*(2/r - 1/a)) > > This can be simplified for a circular orbit (r = a): > > v = sqrt(MU/a) These are the formulas they did not tell us at school, thank you! > The more important thing is what Dan Schultz pointed out. At 300 km altitude, atmospheric drag is a significant factor in a continuous drain of orbital energy. This is less at 500 km and almost insignificant starting around 800 km. The drop off is because drag is: > > 1. proportional to atmospheric density which drops off quickly with increased altitude. > 2. also proportional to the square of the speed relative to the atmosphere. > > If you can get above 800 km without using up a lot of your fuel, you have a chance to make something workable. >From the last few cubesat rides I reckon that going there instead of only to 300 km is not that impossible. Regards Patrick -- Engineers motto: cheap, good, fast: choose any two Patrick Strasser <patrick at wirklich priv at>

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AMSAT table at Cochise ARA hamfest (Sierra Vista AZ) on Saturday morning
by Patrick STODDARD (WD9EWK/VA7EWK) 02 May '13

02 May '13

Hi! I will have an AMSAT table at the Cochise Amateur Radio Association's Larry Warren Hamfest in Sierra Vista AZ this Saturday (4 May). The hamfest starts at 0700 local time (1400 UTC), running until the prize drawing at noon (1900 UTC). The hamfest is at the club's Green Acres Field, east of Sierra Vista and the Fort Huachuca base on Moson Road, south of AZ-90 in grid DM41. More information about the hamfest is available at: http://www.k7rdg.org/ During the hamfest, WD9EWK will be on various satellite passes for demonstrations to the hamfest crowd. Please call if you hear WD9EWK on the pass. For the SSB satellites, I tend to start out about 10 kHz above the center of the transponder. All QSOs will be uploaded to the Logbook of the World after the hamfest. If you would like to receive a WD9EWK QSL card, please e-mail me directly with the QSO details. No card or SASE is required. After the hamfest, I will drive to some of the rarely-heard grids near the Arizona/New Mexico border. If traffic and weather cooperate, I hope to operate from the DM51/DM52 and/or the DM52/DM53 boundaries. A good way to see where I am located is APRS, looking for WD9EWK-9: http://aprs.fi/WD9EWK-9 In addition to APRS, I will try to post updates to my Twitter feed (@WD9EWK) during Saturday from the hamfest and wherever else I operate from. For those not on Twitter, this is also available at: http://twitter.com/WD9EWK 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/

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NASA's First Mission Control Centre
by B J 02 May '13

02 May '13

http://www.nasa.gov/multimedia/podcasting/MCC-History.html 73s Bernhard VA6BMJ @ DO33FL

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Re: Path to HEO
by Burns Fisher 02 May '13

02 May '13

One thing that would seem to be a concern to me is how to keep the attitude steady while the ion engine is firing. Yes, not much thrust, but to make the most of it, you want it pointing in as close to the ideal direction as possible. I don't know how the various probes like Hayabusa and Dawn do it.. Cold gas? Gyro? I would not think a bar magnet would be good enough (certainly not for deep space probes, but even for earth orbit). Starting to get more complicated. Another thought about the really cool energy analysis done by KK6MC: Besides the duty cycle imposed by wanting to be out of eclipse, there is another duty cycle imposed by the starting orbit and the desired eccentricity. For example if you were starting from a highly elliptical GTO and you want to get to high circular, you need to thrust mainly at the apogee in order to raise the perigee. If you are circular and you want to be elliptical with perigee equal to the starting height, you thrust at what will be the perigee to raise the apogee. (Of course you probably want to raise both ends some, and you may want to change the plane too but that's the general idea.) Thanks for bringing this up...great thought experiments, and that's how real projects begin! Burns, W2BFJ

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Re: Path to HEO
by Joe Leikhim 01 May '13

01 May '13

Thinking way outside the box, what about some sort of phased array using dipoles, which has the boresight synthesized to point at earth. In other words, don't use fuel to reorient the bird, electronically steer the phase of the antennas so that earth is in focus. -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida JLeikhim(a)Leikhim.com 407-982-0446 WWW.LEIKHIM.COM

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Re: Imagine RIT Festival May 4th - AMSAT Fox-2 Maximum PowerPoint Tracker Senior Design Project Exhibit
by Bill W1PA 01 May '13

01 May '13

Nice job, Bryce. Regards, Bill W1PA (RIT '87)

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