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

EZnec experts? (cubesat Circ Antenna)
by Robert Bruninga 06 Dec '13

06 Dec '13

EZnec kibitzers welcome: See this model image: http://aprs.org/psat/VHF-circ-tuned-ask.gif We are placing two ¼ wave VHF whip antennas on a single feed at the corner of a 1.5U cubesat. We want them +/-45 degrees out of phase so that we get cross polarization when paralleled to a single feed point for simplicity. Modeling each one individually, we got the desired short one to -45 degrees with a coordinate of 23.04” and the long one to +45 degrees with a coordinate of 25.7”. Great… But when we connect them both to the same feed point, we get a combined real R term about half of the others as expected, but do not get the desired J0 term but get something near -45 degrees and a resonance several MHz higher. To fix that, we lengthened each exactly the same amount to get the resonance down to 145.8 MHz and J=0 term. Good antenna…. The QUESTION IS: Are they still 90 degrees out of phase and will they work as a cross polarized antenna? And how can we verify that? The feed point is the center of a 0.1” wire between the cubesat wire frame and the combined end point of the antennas which are also 0.1” above the top of the cubesat. Maybe I should have included both wires in the original model, but only connected one at a time to a source and grounded the other one while trying to find their individual +/-45 degree lengths. This way, their passive action as a possible counterpoinse to the whole frame may be accounted for. Also, to get within the 500 data points for EZnec, we had to make all of the wire model 1” segments be a single segment per wire. Is fidelity maintained with only 1 segment per 1” wire? Bob, WB4APR

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12 CubeSats launched with NROL-39
by Gregory Beat 06 Dec '13

06 Dec '13

Twelve CubeSats are set to launch aboard an Atlas V rocket with the NROL-39 primary payload from Vandenberg AFB in California on December 5, 2013. The CubeSat payloads have been provided through NASA's Educational Launch of Nanosatellites (ELaNa) program and the NRO's Mission Integration Directorate (MID). CubeSat Project will be using the #cubesat IRC channel to coordinate object identification. -- Justin Foley KI6EPH CubeSats on the Atlas V GEMSat Launch 2013 http://cubesat.org/index.php/missions/upcoming-launches/134-l39-launch-alert Follow ongoing chat on the #cubesat IRC channel see http://www.cubesat.org/index.php/collaborate/ground-operators == w9gb Sent from iPad Air

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NROL-39 TLE
by M5AKA 06 Dec '13

06 Dec '13

1 99991U 00000 13340.43204282 0.00000000 00000-0 00000-0 0 0006 2 99991 120.5031 227.3464 0297856 339.9554 93.2232 14.64196995000009 Successful Launch of NROL-39 CubeSats http://amsat-uk.org/2013/12/06/successful-launch-of-nrol-39-cubesats/ Delfi-n3Xt Update December 5 http://amsat-uk.org/2013/12/05/delfi-n3xt-update-december-5/ ---- 73 Trevor M5AKA AMSAT-UK website http://amsat-uk.org/ Facebook https://www.facebook.com/pages/AMSAT-UK/208113275898396 Twitter https://twitter.com/AMSAT_UK ----

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NROL-39 launch seen in San Diego
by Phil Karn 06 Dec '13

06 Dec '13

Kimberly and I picked it up visually here in San Diego about a minute before staging. Because of the high inclination (reportedly 123 degrees) it was faint and far away, but it was unmistakable in binoculars despite local light pollution. The plume was gradually broadening as it rose into thinner air. It disappeared at staging. I didn't expect to see the Centaur upper stage at night since it burns H2/O2. The primary payload is a NRO spooksat (reportedly radar imaging) so coverage stopped at fairing jettison. No word on the cubesat deployments, but they probably won't be for a while. Several are supposed to transmit on 70cm.

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Re: AO-73 QSOs on the beacon?
by Michael Fletcher 06 Dec '13

06 Dec '13

AO-7, mode B, happens pretty often... --

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AO-73 QSOs on the beacon?
by n0jy 06 Dec '13

06 Dec '13

During the eclipse passes while copying telemetry with my Funcube Dongle Pro + I am hearing SSB QSOs on the beacon frequency. They usually "walk" across it but what puzzles me is that the website info indicates that the transponder passband is well away from the beacon frequency. Am I experiencing some weird stuff with my Dongle or is it possible for stations to work on an uplink that puts their downlink on the beacon frequency? Thanks, Jerry N0JY

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Oscar-10 AMSAT Satellite Spacecraft Kiln Dry Wood Model Large New
by Stefan Wagener 06 Dec '13

06 Dec '13

Here you go! Ebay # 321247180758 Anyone has one of these? Stefan

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Triton-1 and PI9CAM 25 meter dish
by M5AKA 05 Dec '13

05 Dec '13

Triton-1 recovered with help of PI9CAM 25 meter dish http://amsat-uk.org/2013/12/05/triton-1-recovered-with-help-of-pi9cam-25-me… ---- 73 Trevor M5AKA AMSAT-UK website http://amsat-uk.org/ Facebook https://www.facebook.com/pages/AMSAT-UK/208113275898396 Twitter https://twitter.com/AMSAT_UK ----

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Lituanica SAT-1
by andy thomas 05 Dec '13

05 Dec '13

I was pleased to work on HF (30m CW) yesterday LY2013SAT - evidently very proud of the upcoming launch. Looking forward to hearing her from orbit. 73 de andy g0sfj

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(no subject)
by Ellis Foley 05 Dec '13

05 Dec '13

Hi Joe, the link below is for a coax calculator. its self discribatory, it will let you see the difference the various coax's have agains each other vs freq. The hight you go in Freq, the lossier the cables are. Two good barometers are to run comparisons on 2m and 400 mhz. ie. 144, and 432 Mhz, 100ft runs leave the 100 watt input the same and watch the watts out !. that will give you a really good idea of cable loss. now you can see why I recommended some RG213 over the RG58 you're running now. you are losing over 50% of your power to the cable loss. that's way to costly for operation performance. We all cut corners but there are some things not to cut and running "a good" not necessarily the best feed lines out there is a good thing to get in the habit of. and a good cable will last you your lifetime almost. Ok have fun with the calculator. de Ellis WA1RKS http://www.saarsham.net/coax.html

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