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

Crossbooms ... my pennyworth.
by john hackett 10 Jan '07

10 Jan '07

Hello All, Stating the obvious ... if one mounts the aerials as per a Wimo satellite X-Quad ... (using counterweights if necessary) ... one eliminates the crossboom problem entirely. I've compared this kind of system against my more usual 2 x 6 + 2 x 6 homebrew array for 2m and 70cm ... (each aerial mounted at 45 degrees in relation the other) ... and correctly phased for switchable CP. In my humble opinion, on LEO's the squint experienced just doesn't warrant the effort of being (theoretically) correct. It did make a 'slight' difference on AO-10 and AO-13 (HEO's) but still hardly worth the effort of being "technically correct". Others may have a different opinion ... which of course, they have evey right to have. I respect that. 73 John. <la2qaa(a)amsat.org>

7 8

icom 821h problem
by Bruce 10 Jan '07

10 Jan '07

i have an icom 821h. sometimes when i turn it on, both the main and the sub band receive lights are flashing together from green to orange. when this happens, i can transmit fine but there is no audio. turn it on and off a bunch of times and nothing changes. then all of a sudden one day, it will work just fine. of course in the meantime, there is no audio on either band. adjusting the squelch all the way open or closed changes nothing. i can see the s-meter move when a signal is received so that works fine. any ideas? please email me directly. 73...bruce -- Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0100z on W0KIE Intelsat Americas, T1, 6.2/6.8Mhz Also streaming MP3 at http://www.amsatnet.com Latest satellite news on the ARRL Audio News http://www.arrl.org

1 0

RAFT Satellite PSK-31 mode next week
by Robert Bruninga 10 Jan '07

10 Jan '07

Next week, we will enable the PSK-31 transponder on RAFT. This transponder is 28.120 USB MHz PSK-31 SSB uplink and 2 meters FM down. Both RAFT and ANDE (and PCSAT-1 this week) are working fine on orbit for those with a big enough OSCAR satellite array to hear the weak 2 meter downlink. PCSAT-1 is much stronger and has passes that are almost 15 minutes in length and can be worked horizon to horizon with a good beam. ANDE and RAFT are only usable above about 10 to 15 deg with a good beam for only a central 3 minutes or less. RAFT packet-to-voice mode has been enabled for the first 3 weeks and several stations have made contact... See web page: http://www.ew.usna.edu/~bruninga/ande-raft-ops.html Next week starting Tuesday 16 Jan, we will enable the RAFT PSK-31 transponder for similar experiments. Here is what it takes once the PSK-31 mode has been enabled: 1) Read the user-service-agreement on the above web page 2) Someone in the footprint must do a packet CONNECT RAFT 3) That will bring up the 10m RX and 145.825 TX for 1 minute 4) Anyone sending PSK-31 or CW on 28.120 MHz USB should be heard The transponder will time out after 1 minute (maybe later we can extend that time depending on usage). Remember that the footprint of RAFT is an order of magnitude smaller than PCSAT-1 and so it is hard to hear except when a high pass and the duration is only a few minutes. With PCSAT-1 fully alive this week and next, we are seeing over 80 different stations (the maximum depth of the live capture page http://pcsat.aprs.org ) in under 8 hours. Just today another satellite was launched onto 145.825 so now there are 5 satellites there! PCSAT-1, ANDE, RAFT, UO-11 and now Pehunesat. All but UO-11 use standard 1200 baud AX.25 packets. Bob Bruninga USNA Small Satellite Lab

1 0

Pehuensat-1 passes USA
by Mr Jeffrey Ross 10 Jan '07

10 Jan '07

Hello, anyone with a guesstamit when this sat will pass over the USA please let us know here so we can turn on our rigs/tncs to the freq, thank you in advance, kc8gkf west michigan usa

2 1

Elmering help needed in Huntsville Alabama area.
by Vince Fiscus, KB7ADL 10 Jan '07

10 Jan '07

Actually the Help is needed in Madison, a little east of Huntsville. There is an elderly couple that need help setting up an amateur radio station. They aren't thinking anything complicated, just a small vertical for HF, but they are to old to do it. If you can, and would like to help them set up their station and elmer them a little to get on the air, please email me. I'm in MT and not able to help them. Thanks 73 KB7ADL

1 0

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

1 0

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

2 1

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

1 0

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)

2 1

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

2 1