Amsat-dc (INACTIVE) February 2013

5 participants
7 discussions

inquiry about homebrew az-el systems
by Samudra Haque 28 Mar '13

28 Mar '13

Hi, about two years ago, I started a design for a robotics class project of a AZ-EL rotator controller system, and a hardware package for the mechanism for rotating an antenna in any direction subject to mechanical stops. The system would have been able to handle regular and flip modes. I didn't do anything more than calculations, and moved on to building a classroom instructional robot then. Lately, as I am setting up (K3GWU, the George Washington University Amateur Radio Club and Research Station) I find that the price of az-el systems such as G5500 + Yaesu AZ-EL rotors are expensive, and are not typically available on an affordable basis on Ebay or eham.net etc. Well, of course, expensive is a relative term, for a student hobby organization, it's a lot, and I guess for small ham operators it is also moderately expensive. This may be a frequently asked topic: does any one have experienced with (tested) kit designs for AZ-EL rotors that can be made with parts from current suppliers ? I know there are a number of controller designs, but I am interested to know if there are any options for suppliers of the required gears/motors etc. I have located several large AC motors / DC motors at my university mechanical engineering workshop, but they are not all guaranteed the same specs. I now realize if I do embark on a actual design process with my model/simulation/hardware, it would be nice to build several of these all at once to share the development cost over the production run, and ensure those who want a cheap AZ-EL system can get one. Otherwise the production cost of one heavy duty system is going to be quite high. I hope some of you may have suggestions for me, both (+) and (-) or perhaps (~) in nature. I thought amsat / amateur radio folks have a common need to encourage homebrew activity to keep their brain cells in working condition? I'm opening this question up to the national US audience, and welcome any discussion on the challenges of making the ever-so-important azimuth-elevation rotor. I've studied some of the alternatives: Alliance U100 and Yaesu G-5500. I think we can do better in 2013. But ideally, to allow the wide adoption of AMSAT ground stations, what price point would the system have to be to make it worth building ? 73 de N3RDX George Washington University

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inquiry about homebrew az-el systems (Samudra Haque)
by Pat Kilroy 25 Feb '13

25 Feb '13

Hi Samudra, Gosh, here are some of the oodles of plans out there for different az-el antenna pointing solutions to get you started. See below. I'm sorry I don't have info on motor suppliers or the other items you mention. Hope these might be helpful none the less to you and others. Cheers, Pat Kilroy N8PK >From ANS-020 released Saturday, January 19, mainly introducing our Workshop on Portable Satellite Ground Stations, but includes buried nuggets on antennas and az-el: Links for antenna ideas: http://arrowantennas.com/ http://www.elkantennas.com/ http://www.g6lvb.com/homebrewarrow.htm http://www.amsat.org/amsat-new/information/faqs/crow/index.php http://www.amsat.org/amsat-new/echo/Az_El_Pos.pdf http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf http://www.amsat.org/amsat-new/tools/downloads/iROTOR.pdf http://www.arrl.org/shop/The-ARRL-Satellite-Handbook/ http://ac6v.com/antprojects.htm Links for software ideas: http://www.amsat.org/amsat-new/tools/software.php http://www.amsat.org/amsat-new/tools/ http://www.moetronix.com/spectravue.htm http://www.amsat.org/amsat-new/information/faqs/resguide.pdf http://sdrsharp.com/ >From ANS-048 released Saturday, February 16: http://www.vk3um.com and http://www.vk5dj.com/satellite.html and then derived: http://www.muratamems.fi/sites/default/files/documents/sca61t_inclinometer_… and http://www.digikey.com/product-detail/en/SCA61T-FA1H1G-1/551-1005-1-ND/7513… The LVB Tracker Box by Howard Long, G6LVB: http://store.amsat.org/catalog/product_info.php?products_id=63 >From ANS-041 released Saturday, February 9: ANS Archives http://amsat.org/pipermail/ans/ Me? I must be choosy on which wheels I re-invent, especially when I need proven/reliable operations out of a station component, such as Az-El motion. I use a heavy duty camera tripod to steer portable antennas, and I cheated and got the Yaesu G-5500 combo ($730) for portable, semi-portable and fixed operations: http://www.hamradio.com/detail.cfm?pid=H0-002765 -----Original Message----- From:[email protected] Sent: Sunday, February 24, 2013 03:00 PM To: amsat-dc(a)amsat.org Subject: AMSAT-DC Digest, Vol 8, Issue 13 Send AMSAT-DC mailing list submissions to amsat-dc(a)amsat.org To subscribe or unsubscribe via the World Wide Web, visit http://amsat.org/mailman/listinfo/amsat-dc or, via email, send a message with subject or body 'help' to amsat-dc-request(a)amsat.org You can reach the person managing the list at amsat-dc-owner(a)amsat.org When replying, please edit your Subject line so it is more specific than "Re: Contents of AMSAT-DC digest..." Today's Topics: 1. inquiry about homebrew az-el systems (Samudra Haque) ---------------------------------------------------------------------- Message: 1 Date: Sat, 23 Feb 2013 18:59:35 -0500 From: Samudra Haque To: "amsat-dc(a)amsat.org" , Amsat-bb Subject: [amsat-dc] inquiry about homebrew az-el systems Message-ID: Content-Type: text/plain; charset=ISO-8859-1 Hi, about two years ago, I started a design for a robotics class project of a AZ-EL rotator controller system, and a hardware package for the mechanism for rotating an antenna in any direction subject to mechanical stops. The system would have been able to handle regular and flip modes. I didn't do anything more than calculations, and moved on to building a classroom instructional robot then. Lately, as I am setting up (K3GWU, the George Washington University Amateur Radio Club and Research Station) I find that the price of az-el systems such as G5500 + Yaesu AZ-EL rotors are expensive, and are not typically available on an affordable basis on Ebay or eham.net etc. Well, of course, expensive is a relative term, for a student hobby organization, it's a lot, and I guess for small ham operators it is also moderately expensive. This may be a frequently asked topic: does any one have experienced with (tested) kit designs for AZ-EL rotors that can be made with parts from current suppliers ? I know there are a number of controller designs, but I am interested to know if there are any options for suppliers of the required gears/motors etc. I have located several large AC motors / DC motors at my university mechanical engineering workshop, but they are not all guaranteed the same specs. I now realize if I do embark on a actual design process with my model/simulation/hardware, it would be nice to build several of these all at once to share the development cost over the production run, and ensure those who want a cheap AZ-EL system can get one. Otherwise the production cost of one heavy duty system is going to be quite high. I hope some of you may have suggestions for me, both (+) and (-) or perhaps (~) in nature. I thought amsat / amateur radio folks have a common need to encourage homebrew activity to keep their brain cells in working condition? I'm opening this question up to the national US audience, and welcome any discussion on the challenges of making the ever-so-important azimuth-elevation rotor. I've studied some of the alternatives: Alliance U100 and Yaesu G-5500. I think we can do better in 2013. But ideally, to allow the wide adoption of AMSAT ground stations, what price point would the system have to be to make it worth building ? 73 de N3RDX George Washington University ------------------------------ _______________________________________________ AMSAT-DC mailing list courtesy of AMSAT-NA AMSAT-DC(a)amsat.org http://amsat.org/mailman/listinfo/amsat-dc End of AMSAT-DC Digest, Vol 8, Issue 13 ***************************************

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Re: Fwd: inquiry about homebrew az-el systems
by Tom Clark 25 Feb '13

25 Feb '13

I responded to Samudra Haque after a couple of preliminary Emails with this idea on lo-cost az/el rotors. I presented the idea at an AMSAT-DC meeting 3? years ago and showed a working kludge example. Somewhere in my archives I have the Powerpoint from then and I will dig it up if there is any interest, particularly from someone who wants to do some development! The rotor scheme I described in my presentations is based on the DISEQC consumer antenna control protocol (seehttp://en.wikipedia.org/wiki/DiSEqC <http://en.wikipedia.org/wiki/DiSEqC>) pushed by EUTELSAT and found in nearly every backyard satellite dish system (see http://www.eutelsat.com/satellites/pdf/Diseqc/associated%20docs/position_ap…). The DISEQC scheme superimposes DC (to run the rotors, switches, downconverters, etc) plus RF (typically 500-1500 MHz IF satellite downlinks) plus control (PWM 22 kHz tones) and it has an amazingly rich instruction set. Many BUD (Big Ugly Dish) receivers include DISEQC controllers for controlling antenna position, polarization, bandswitching, etc. Most of the DISEQC rotors cover only 180 degrees and are very suitable for elevation with 1 degree precision (see http://www.sadoun.com/Sat/Products/PowerTech/Sadoun-DG380B_HH_Motor.htm) for example. Sadoun is a main suplier in USA. However I have found one 540 degree DISEQC Azimuth rotor (http://www.solidsignal.com/pview.asp?p=rotr100&d=eagle-aspen-rotr100-one-ca… <http://www.solidsignal.com/pview.asp?p=rotr100&d=eagle-aspen-rotr100-one-ca…> ). Total cost for a pair of az/el rotors is < $200 but the antennas that could be controlled must be pretty small. My application was for a solar radio telescope using a couple of small DirectTV Ku-band dishes. I'd LOVE to find someone who was interested in developing a microcontroller/interface for DISEQC az/el use. The coding should be pretty simple. Also someone needs to figure out a scheme to adapt the "crooked pipe" on the elevation rotor to couple to a real antenna. Let me know if you can find someone who is interested. Also, if anyone is interested, you might want to browse the Sadoun & Solid Signal web sites where you will also find DISEQC controlled 75 ohm RF switches good for low power use well into the microwave spectrum. 73, de Tom K3IO (ex W3IWI)

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AMSAT-DC Spring Workshop 2013 (Planning 1.0)
by Kilroy, Patrick L. (GSFC-5680) 19 Feb '13

19 Feb '13

Dear Bruce WA3SWJ, Dan N8FGV, Steve KS1G and all, May I run a few things by you for your advice and comments regarding our coming spring work- shop? 1. I got a blurb into the next AMSAT Journal that members will see in their snail mail boxes soon. Page 13, nice! We are official. ;-) (See the basic info about this crazy idea below from an earlier post on our amsat-dc list if you need a reminder of the vision of this workshop.) JoAnne was great in helping to make this so. Yayyyy! The day will be lots of fun! 2. Since the workshop will be on site at Goddard, I will need to get every single person's name, nationality and current town of residence into the NASA Goddard security folks so they can make a one-day non-escorted badge for each participant. Unfortunately, we need to emphasize to people to register even if they are not sure they can make it, because registration will close about a week before the event. This is NOT like your weekend hamfest! Problems? Any who wish to attend who are NOT a USA citizen may do so ONLY AS LONG AS they contact me before February 15, because there are special procedures in place to make this so. And they must follow them within other deadlines. Unfortunately, NO exceptions to this procedure. Bonus: there will be NO FEE to use the facilities. YOUR tax dollars at work! But BTW, in the news today, the fiscal cliff has been pushed off until March 1. Our use of the facilities ARE CONTINGENT on these circumstances, and others. Can we accept these caveats? 3. Price Stucture. Trade study/options. In rough order of logic or importance, kinda. . . . OPTION A. No charge to anyone. No coffee in the morning. No lunch on site. No frills. The lunch break would be at noon, normally for an hour. But to get everyone back, on time, will be a disruptive pain. (Been there.) I'd like to end the event by, say, 3:30 PM or what ever you think. (Based on a 9:00 AM start time?) I beleive an off site lunch break will put a damper on our progress. OPTION B. A modest donation requested. $20? That will get us coffee/tea/juice in the morning and Subway sandwiches (catered) with sodas at noonish, enjoyed in place (but not near one's satellite hardware, of course). The event goes through lunch unbroken. We will need a point of contact, actually two. One to collect the money and one to take care of the food, condiments, utinsils, cups, napkins, set up tables, etc. Can you volunteer yourself? Or better yet, have your wife/GF/significant other volunteer to work the food issues? That would be awesome! OPTION C. If we request a donation for admission, then "what if" it is structured? That is, shall we consider a main donation of, say, $25 for "normal" admission, and a lesser fee for either students or for those who bring at least three ("significant") hardware items to set up, show and discuss with others? The lifeblood of this event will be having at least ten stations set up for show and tell. Perhaps an offset of the requested donation amount will encourage people to bring stuff. Thoughts?? OPTION D. Shall we hold one or more raffles or silent auctions? That is, shall we invest in a FUNcube Dongle Pro+, an ARROW antenna or an Elk antenna and then make available raffle tickets? Or a written auction with a minimum donation request? If so, we will need a volunteer to run with this. (I can offer some seed money and accept some risk, but I need to delegate this to a trustworthy individual.) Volunteer? Thoughts? Any leftover dollars can be either donated directly back to AMSAT-NA or invested in needs for a workshop next year. 4. It looks like we are set with the date of Saturday, March 23, with no rain date. We can still set the time. Open doors at 9:00 AM for those who need to set up? With the "program" to begin at 10:00 AM? Or later? Shall we advertise that the program ends at 3:30 PM? Or earlier? Or later? 5. Shall we solicit formal talks or presen- tations too? (I was not planning this initially.) Limit the talk time to ten minutes? Sixty minutes? Then we ought to delegate an individual to coordinate the presenters in advance? Volunteer? Otherwise, No formal talks, but allow individuals to address the group as issues come up at the tables? No volunteer needed to coordinate this. I can probably do it on the fly during the event. 6. I will set up a table with my humble but growing portable satellite station on the evening before the event. Would anyone like to join me, either to move MY gear, or move in YOUR own gear? That way, I/we will be free in the morning to help or direct others as needed. 7. We want this to be a successful workshop. What other important framework item needs to be discussed? Thoughts? Thank you for your support! Cheers, Pat N8PK Mr. Patrick L. Kilroy Integration & Test Manager NASA Goddard Space Flight Center Building 5, Mail Code 568 Greenbelt, Maryland 20771 Phone: +1-301-286-1984 E-mail: Patrick.L.Kilroy(a)nasa.gov Web: http://simsat.net/ (outreach) ---------------------------------------------------------------------- Date: Thu, 6 Dec 2012 17:32:03 -0500 From: Stephan Greene <ks1g04(a)gmail.com> Cc: "amsat-dc(a)amsat.org" <amsat-dc(a)amsat.org> Subject: [amsat-dc] Re: AMSAT-DC Spring Workshop 2013 Proposed Excellent idea! I'm unsure if I can make the entire day or at all but I am very interested. Besides the Arrow & the semi-portable setup (vehicle required!) I used for Field Day, I have 50% of a homebrew antenna setup - 6 element WA5VJB cheap yagi for 2M (I'll add it works FB for meteor scatter, too!). Need to make a 70cm version and possibly a smaller/more portable 2M. And get back on the birds after tearing the station apart for FD and not putting it all back together! 73 Steve KS1G ---------------------------------------------------------------------- On Thu, Dec 6, 2012 at 11:46 AM, patrick.l.kilroy(a)nasa.gov wrote: > I WISH TO PROPOSE the AMSAT-DC Spring Workshop > 2013, to take place on Saturday, March 23, at > the NASA Goddard Space Flight Center in > Greenbelt, Md. It will be a nearly all-day > event. > > "Workshop on Portable Satellite Ground Stations" > > ... is the title, where attendees will learn > about and develop their own portable ground > station and show off their wares which will > feature one or more of the following: > > 1. One's own laptop computer, with appropriate > software installed, such as for satellite tracking, > SDR receiver control, antenna control (optional), > audio recording and any other apps, for example. > > 2. The FUNcube Dongle Pro receiver or equivalent, > emphasizing *receiving* and not including the > transmit side at this particular time. See the > links below for ideas about software, receivers > and antennas. > > 3. Antennas for 146 MHz and 436 MHz with a > mounting means, such as on a camera tripod, small > mast, homebrew PVC, or other portable creation. > Your antennas can be either the Arrow, Elk or > equivalent, or homebrew. Polarization linear or > circular. Antenna Az-El movement can be by hand > or controller (manual activating or automated, > fully or partially). > > Everything, or almost everything, ought to be > designed to run from a 12-volt source of your > choosing. > > Additional details will be determined by a small > humble steering committee that YOU can influence > early on. And speaking of that, . . . > > May I include you, among others, on my steering > committee? If not, that's okay, but I need to > know if you'd like to participate. Can you > bring in some gear to assemble and to show off > to others attending? > > Perhaps we could meet in person, telecon by > phone, or by EchoLink conferencing soon as a > group to further outline this event? > > Foremost, if needed, an alternate date can be > selected, from either March 9 or 16, or moved > into April on a Saturday AFTER the Greater > Baltimore Hamboree and Computerfest of April 6, > as long as we decide in the next week or two. > > Are you in?? > > Can you help organize? Or attend? What might > you bring? > > Thoughts? > > Thanks, > > Pat Kilroy > N8PK > amsat area coordinator > > Links for antenna ideas: > http://arrowantennas.com/ > http://www.elkantennas.com/ > http://www.g6lvb.com/homebrewarrow.htm > http://www.amsat.org/amsat-new/information/faqs/crow/index.php > http://www.amsat.org/amsat-new/echo/Az_El_Pos.pdf > http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf > http://www.amsat.org/amsat-new/tools/downloads/iROTOR.pdf > http://www.arrl.org/shop/The-ARRL-Satellite-Handbook/ > http://ac6v.com/antprojects.htm > > Links for software ideas: > http://www.amsat.org/amsat-new/tools/software.php > http://www.amsat.org/amsat-new/tools/ > http://www.moetronix.com/spectravue.htm > http://www.amsat.org/amsat-new/information/faqs/resguide.pdf > http://sdrsharp.com/ > > Links for receiver ideas: > http://www.funcubedongle.com/ > http://www.amsat.org/amsat/intro/sats_faq.html > http://www.funcubedongle.com/MyImages/SpectravueConfigurationForFCD.pdf > http://sdrsharp.com/ > > > "People don't care about how much > we know, until they know how > much we care." - Jack Vieira > ----------------------------------------------------------------------

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Going Once, Going Twice
by Kilroy, Patrick L. (GSFC-5680) 13 Feb '13

13 Feb '13

Last call . . . Do we have a volunteer to take over the food and planning role? See the details from my previous message as shown below. Or call any time, 301-286-1984. We need to hear asap if not sooner. Thanks. Sincerely, Pat -----Original Message----- Date: Wed, 6 Feb 2013 14:37:16 -0600 From: Patrick.L.Kilroy(a)nasa.gov To: amsat-dc(a)amsat.org Subject: [amsat-dc] Special Workshop Volunteer Needed DOES ANYONE KNOW someone who can serve as our chairperson on food and drink for our AMSAT-DC workshop on Saturday, March 23? I know it does not sound like a glorious position, but we need to identify someone soon! By COB this Monday, February 11. What does he or she do? . . . He or she is directly involved in the planning of the food and drink at our nearly day-long event. You can also add purchasing, pickup or delivery, serving or presentation, and accounting. Not a very technical position but extremely important! If we don't get a volunteer for this then it will change a dynamic of our day. We would need to delete coffee and breakfast- type items early on, as well as lunch and snacks later. It would be okay to announce for each person to bring their own brown bag lunch, but that may not be practical, and I really want to avoid the disruption of folks leaving the site during lunch time. Even worse, entertaining starving souls amongst us. BTW, hiring someone to handle all this is possible, but it would drive up the $$ donation for each person attending. Thoughts? Thank you very much. Cheers, Pat Kilroy N8PK AMSAT Area Coordinator Phone: 301-286-1984 voice messages ------------------------------ End of AMSAT-DC Digest, Vol 8, Issue 9 **************************************

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FW: SpotTheStation
by Kilroy, Patrick L. (GSFC-5680) 07 Feb '13

07 Feb '13

An Eyeball opportunity in about an hour if you can try to look for the ISS outside. Simple info below for all in the greater Maryland-DC-NoVa area! Is the sky clear? http://www.wunderground.com/cgi-bin/findweather/hdfForecast?query=20771 -----Original Message----- From: united-states-maryland-baltimore-washington-parkway-pm-bounces(a)lists.hq.nasa.gov On Behalf Of noreply(a)nasa.gov Sent: Thursday, February 07, 2013 7:57 AM To: United-States-Maryland-Baltimore-Washington-Parkway-PM(a)lists.hq.nasa.gov Subject: SpotTheStation Time: Thu Feb 07 7:00 PM, Visible: 3 min, Max Height: 43 degrees, Appears: SSW, Disappears: SE

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Special Workshop Voluteer Needed
by Kilroy, Patrick L. (GSFC-5680) 06 Feb '13

06 Feb '13

DOES ANYONE KNOW someone who can serve as our chairperson on food and drink for our AMSAT-DC workshop on Saturday, March 23? I know it does not sound like a glorious position, but we need to identify someone soon! By COB this Monday, February 11. What does he or she do? . . . He or she is directly involved in the planning of the food and drink at our nearly day-long event. You can also add purchasing, pickup or delivery, serving or presentation, and accounting. Not a very technical position but extremely important! If we don't get a volunteer for this then it will change a dynamic of our day. We would need to delete coffee and breakfast- type items early on, as well as lunch and snacks later. It would be okay to announce for each person to bring their own brown bag lunch, but that may not be practical, and I really want to avoid the disruption of folks leaving the site during lunch time. Even worse, entertaining starving souls amongst us. BTW, hiring someone to handle all this is possible, but it would drive up the $$ donation for each person attending. Thoughts? Thank you very much. Cheers, Pat Kilroy N8PK AMSAT Area Coordinator Phone: 301-286-1984 voice messages

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Amsat-dc (INACTIVE) February 2013