AMSAT-BB February 2013

131 participants
165 discussions

Re: games with FO-29/AO-7
by Vince Fiscus, KB7ADL 25 Feb '13

25 Feb '13

At 10:03 PM 2/25/2013 +0000, Bob- W7LRD <w7lrd(a)comcast.net> wrote: >When AO-7 is in B mode it's down link is FO-29' uplink. I was thinking, >even though their ground track as seen on Satpc32 do not line up, would >not they be able to "see" each other? Which begs the question, how does >one determine what that "see" part is? Is there a quick back of the >envelope calculation one can do? Keep it simple. >Thanks >Bob W7LRD >Seattle I'm not sure exactly what you're asking Bob, But when each satellites footprints intersect other, then the satellite's are in view of each other. When the footprints don't intersect the earth is in the way. KB7ADL

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Re: phased array
by Joe Leikhim 25 Feb '13

25 Feb '13

Actually there has been a lot of work on steerable arrays on the lower frequency bands. Here is one notable example: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDcQFjA… -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida JLeikhim(a)Leikhim.com 407-982-0446 WWW.LEIKHIM.COM

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games with FO-29/AO-7
by Bob- W7LRD 25 Feb '13

25 Feb '13

When AO-7 is in B mode it's down link is FO-29' uplink. I was thinking, even though their ground track as seen on Satpc32 do not line up, would not they be able to "see" each other? Which begs the question, how does one determine what that "see" part is? Is there a quick back of the envelope calculation one can do? Keep it simple. Thanks Bob W7LRD Seattle

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Pendulum type elevation measurement
by Richard Ferryman 25 Feb '13

25 Feb '13

For some time I have wanted a more accurate antenna elevation measurement system. Shaft encoders are beyond my budget. It seems sensible to use a pendulum operated system. Digging through my 'junk' box I find I have a new Spectrol precision potentiometer still sealed in it's package. This pot is 21mm diameter, has a servo type mount,, ball race bearing, 340 degree track (continuous rotation possible) and specification is 0.5% linearity.and is very low torque. Does anyone know if there are any drawbacks to using this method of position measurement. 73 de Dick G4BBH

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STRaND-1 and AAUSAT3 Heard over Delft
by Wouter Weggelaar 25 Feb '13

25 Feb '13

Hi All, On the 19:10 UTC pass both STRaND-1 and AAUSAT3 Have been received at the ISIS office in Delft. I was using some experimental receivers for this. The STRaND-1 beacon is nice and loud and I measured quite a nice SNR (20+ dB) I used the following KEPS: STRaND 1 44871U 58056A 13056.56369708 .00000000 00000-0 +10239-3 0 334 2 44871 98.7067 247.0547 0006435 302.9022 57.1261 14.35120889200890 Congratulations to the STRaND and AAUSAT3 teams for this great success! I hope to see more mission results in the near future. Wouter Weggelaar PA3WEG

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phased array
by Howie DeFelice 25 Feb '13

25 Feb '13

Hi Samudra, Phased array is a generic term. Stacked yagi's are a phased array :) If you mean electrically steered phased arrays, that's another story. If you mean non-steered phase arrays, that is also another story. As far as I know there has not been much work in the amateur community on electrically steered arrays. For that matter they are not that common in the commercial world either. Even the current Ku/Ka band antenna's used on commercial aircraft for inflight Internet use mechanically steered antenna's. If you meant an array of patches to produce a flat panel antenna that had less mass than a yagi, these are really only practical at frequencies higher than UHF considering the gain to patch area ratio. Howie AB2S

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proper way?
by K4FEG 25 Feb '13

25 Feb '13

/*A question for all of the wizards out there!!*//* */ /*WHAT IS THE ACCEPTED METHOD FOR DETERMINING THE DISTANCES BETWEEN 2 STATIONS ON THE SATELLITES?*/ I am curious as to what is the accepted "/*gold standard*/"? There are several calculators and most are somewhat in agreement but some are not. I just recently found out, myself, that the grid square system is broken down to even smaller units than I imagined. it appears that the divisions continue in the same 2 to 1 ratio and is therefore variable in dimension based on you location on the planet./(closer to the equator the larger the grid further north or south of the equator the smaller the grid)/. It seems that my exact location can be found by entering /*EM55aj84ta*//in the satellite mode on the APRS.fi website, you can actually see my satellite antennas on the back deck of my house with those coordinates! (actually my "old antennas") /One additional question for the learned subscribers of this bulletin board! Is there a distance calculator that can accept up to 10 Alpha/Numeric qualifiers for ultra accurate distance calculations? Or does anyone have an idea how I could create one using EXCEL spreadsheet with embedded formulas? Thank You all Frank K4FEG EM55aj84ta Also I have some forms I have created for multiple contacts on the satellites, these are EXCEL based forms, one is a "Log/Label" it fits on a standard Avery 2x4 shipping label and is an embedded EXCEL table that will let you list up to 7 contacts on a Mini Log on the back of your QSL card, works great with a "rover" station in different grid squares, I'd be happy to share it with any one that wants the file! 73 feg

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packet heard ? STRaND-1?
by Nader Omer 25 Feb '13

25 Feb '13

15:55 many packets ( seen ) on waterfall - looks like 9.6 STRaND-1 ?!!! More info later ! ! I large audio file to revise :) Congratulation to all Nader Omer st2nh

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packet heard ? STRaND-1?
by Nader Omer 25 Feb '13

25 Feb '13

15:55 many packets ( seen ) on waterfall - looks like 9.6 STRaND-1 ?!!! More info later ! Congratulation to all Nader Omer st2nh

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UniBRITE CW
by Yasir Osman 25 Feb '13

25 Feb '13

ST2UOK ground station at the University of Khartoum, Sudan has tracked the first pass over Africa of AAUSAT-3 , STRaND-1 and UniBRITE after the launching in 12:25 UTC, a CW signal with high noise heard and expected to be the beacon of the UniBRITE. As pointed by operators Abubakr, Yasir , Mustafa and Hala.

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AMSAT-BB February 2013