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Re: Crossbooms ... my pennyworth.
by richard＠g3rwl.demon.co.uk 10 Jan '07

10 Jan '07

Gang, Howard >> Howard mentioned the much-documented advantages of polarization switching >> for LEO satellite work. In this same context, is it worth the additional >> work to include the remote logic required for V and H polarizations along >> with RHCP and LHCP? > It's a nice to have, but not as much as being able to switch R/LHCP. I > currently use the WIMO polarisation switches and they happen to have all > four polarisations built in. There used to be a 4-polarisation switcher in old RSGB VHF handbooks but it would only be of use if you plan a lot of terrestrial operations as well as space. A simple RHCP/LHCP switcher using a relay and lengths of coax is in the archives at ftp://ftp.amsat.org/amsat/misc/ant_swit.gif 73 Richard G3RWL

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Re: Crossbooms ... my pennyworth.
by jules＠g0nzo.co.uk 10 Jan '07

10 Jan '07

My crossboom is a light steel tube, with wooden dowel extensions, within the field of the antenna. These were turned down in a lathe and hammered/glued into the steel tube. To waterproof the ends, the wooden bits were stood in a tin of creosote for a week. I must admit that the feeders for the 2mtr beam do actually pass through the field, but as it has such a wide beamwidth, I would assume that any squint is going to be irrelevant. Jules

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satscape
by Jerry Ehlers 10 Jan '07

10 Jan '07

Hi: I installed satscape in my laptop the other day and I have been having Some problems. The predictions has a problem. The time on the prediction is in 24 hour time in stead of UTC. Another thing I noticed was when it changes UTC to the next the calendar day It does not change to the next day. It also shows AOS but not LOS. The other tracking software I have you can go to the menu and correct this Problem. The help page is of no help for these problems. Does anybody have an answer.????? I would like to contact the writer of the software by e-mail but this is not Available like my Nova is. Jerry w0sat -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.8/621 - Release Date: 1/9/2007 1:37 PM

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Doppler and direction calculation?
by n3wwn＠futuretek.cx 10 Jan '07

10 Jan '07

Hi! I've been trying to find the answer to this question using Google, but can't seem to find a complete answer. How can I calculate the doppler shift and direction of travel of a satellite accurately? I have the following information based on the observation point: Longitude Latitude Azimuth Elevation Range Altitude Velocity Phase Eclipse Depth Squint Angle For example (AO-27 - it's the first sat in my test keps): Sat Lon = 82.58 W Sat Lat = 27.10 S Sat Az = 182.93 Sat El = -28.64 Sat Range = 7516.62 km Sat Altitude = 799.74 km Sat Velocity = 7.46 km/s Sat Orbit Num = 69288 Sat Visibility = D Sat Phase = 317.61 Sat Eclipse Depth = -62.93 Sat Squint = 360.00 I'd like to be be able to calculate the doppler for any satellite and any frequency. I'd also like to find out the direction of travel, relative to the lat/lon coordinate system (90 if travelling east, 180 if south, 270 if west, etc). Can anyone help me out here with some equations or point me in the right direction?! Thanks! 73 de Rich N3WWN (FN00fh)

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U.K. Foundation license, M3 callsign, working satellites.
by Dave Aitch 10 Jan '07

10 Jan '07

Are M3 callsigns holders able to work through amateur satellites yet please ? Cheers, Dave. AMSAT UK 5766

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PSLV-C7 lifts off successfully
by Mike Rupprecht 10 Jan '07

10 Jan '07

http://www.zeenews.com/articles.asp?aid=346912 <http://www.zeenews.com/articles.asp?aid=346912&sid=ENV&ssid=27> &sid=ENV&ssid=27 Sriharikota, Jan 10: The PSLV-C7, carrying four satellites, lifted off successfully from the Satish Dhawan Space Centre here. All the four satellites of the PSLV-C7 were injected into orbit at an altitude of 638.7 km, 949.8 seconds after the lift off. The entire process took 20 minutes. Based on the velocity during the first three stages, the fourth stage, an unpowered flight called `Coasting` lasted for 15 seconds, moving purely under the influence of gravity. "We have done it successfully. We have put all four satellites into the required orbit. It was a textbook mission. Our boys have done well," ISRO chairman Dr G Madhavan Nair said after the launch. The PSLV C7 carries four satellites - the 680 kg Indian remote sensing satellite Cartosat-2 and the 550 kg space capsule recovery equipment (SRE-1), Indonesia`s Lapan-Tubsat and Argentina`s six kg nanosatellite Pehuensat-1. 73, Mike DK3WN

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FibreGlass Crossbooms
by john heath 09 Jan '07

09 Jan '07

Hi Chaps, Most of the discussion on this topic is about not having a metal cross booms distorting the antenna radiation patern. I have a further observation after having a glass fibre cross boom in place for 10 years. Its a great way to absorb wind energy which might otherwise cause damage. 10 element on 2m and 17 element crossed yagi on 70cms sway gently in 60mph winds but nothing breaks (so far) All the best for 2007 73 John g7hia

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FiberGlass Crossbooms
by Thomas Martin 09 Jan '07

09 Jan '07

Why are fiberglass crossbooms used on satellite antenna installations?

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Sat688 or LVB tracker?
by Stargate 09 Jan '07

09 Jan '07

Hi all, OK, unless some other option comes up, or there is an incompatibility problem that I am aware of, I have narrowed my list of rotor interfaces down to the following 2.... The LVB at.... http://www.g6lvb.com//Articles/LVBTracker/index.htm The Sat688 at.... http://www2.arrl.org/FandES/tbp/ariss-kits/ I have a Yaesu G-5500 and a FT-847 for the rotor and radio respectively. I intend to use Orbitron for my tracking and radio control software if the above interfaces are compatible. The computer is a PIII 650mhz with 1 serial and 1 USB port. I was thinking of using the serial port for radio control and the USB port for the rotor interface. I am leaning toward the LVB since the PIC can be programmed and re-programmed onboard, and it can be made into the LVB 2 for stand alone operation without the computer control, although it will be a little more expensive to construct. On the other hand the Satt688 is less expensive, and should suffice as well. How important is it to be able to re-program the pic? All comments appreciated, Thanks, RoD KD0XX A good friend will come and bail you out of jail, A TRUE friend will be sitting next to you saying..... "DAMN THAT WAS FUN"

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Re: RAFT/ANDE Telemetry Web Pages
by David Johnson 09 Jan '07

09 Jan '07

Hi Mike, Fixed, thanks. - Dave Mike Rupprecht wrote: > Hi Dave, > > regarding the temperature value for RAFT : > > T#246,080,107,059,220,002,10001000,999 > ^^^ > > CH5 - TX Temperature 9e-6*v³ + 0.0031*V² + 0.7019*V - 33.024 > > = (0.000009 * 2 ^ 3) - (0.0031 * 2 ^ 2) + (0.7019 * 2) - 33.024 > > = -31,632528 °C > > Could you check this, please? > > 73, Mike > > -----Ursprüngliche Nachricht----- > Von: amsat-bb-bounces(a)amsat.org [mailto:[email protected]] Im > Auftrag von David Johnson > Gesendet: Dienstag, 9. Januar 2007 21:57 > An: amsat-bb(a)amsat.org > Betreff: [amsat-bb] RAFT/ANDE Telemetry Web Pages > > Hi, > > A very simple web page has been created for RAFT at: > > http://www.g4dpz.me.uk/ANDE/RAFThome.do > > This URL may change if it gets a lot of use or we think of more features > > to add. > > The existing ANDE telemetry web site has had a few cosmetic changes: > > http://www.g4dpz.me.uk/ANDE/home.do > > 73 > > Dave > G4DPZ > > _______________________________________________ > 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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