April 2010 - AMSAT-BB - mailman.amsat.org

Subject: Re: AO-7 Mode C? (Or other reason for varying signal strength?)
by Peter Jordahl 07 Apr '10

07 Apr '10

It seems to me (presumptuous since my only satellite activity is reading the group!) that most of the responses suggest causes that would not be so sharply defined as Bill's observations. He says Either 0.7 degrees OR 4-5 degrees not a continuum of values. I would have to ask if there is any correlation with day of week, local weather conditions (also a continuum of values) or AO-7 mode immediately prior to the mode it is in when the observations are made (IIRC the mode can switch at random). Can a correlation be made between the elevation at AOS and the signal level at nearest approach? 73 Pete K5GM AMSAT LM. Pete Jordahl, K5GM k5gm(a)amsat.org

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KC0YBM - Chris please contact me
by Michael Wolthuis 07 Apr '10

07 Apr '10

Chris (KC0YBM), If you read the BB please contact me at ³kb8zgl at kb8zgl.net² as your email is not listed on your QRZ page and I haven¹t found it through any other ham websites or searches on Google. Thanks, sorry for the bandwidth all, Mike kb8zgl

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Dayton Rooms
by Martha 07 Apr '10

07 Apr '10

Again a friendly reminder that the cutoff date for the AMSAT block of rooms in Dayton is April 13th. If you are planning to stay with us, please call me at 301-589-6062 to make your reservation. I will need a credit card number to hold the room. -- 73- Martha

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Dayton SDR forum speakers sought
by Robert McGwier 07 Apr '10

07 Apr '10

On Friday, May 14, I am the moderator (and speaker) at the SDR forum at the 2:30 PM - 5 PM session. I have two speakers (Scotty on openhpsdr, and I speak on general SDR topics). I need to fill out this time and this leaves at least 1.5 hours to fill. I would like to get this settled as soon as possible. Let me know if you are interested in making a presentation. Also, FYI, I will be the AMSAT/TAPR banquet speaker on Friday night. In addition to my forum, SDR, paper delivery with Joel Harrison, work in Flex booth, etc. this will be one of the busiest Dayton's for me in years. I look forward to seeing many of you. Bob McGwier N4HY

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Heil Headset Thank's
by David 07 Apr '10

07 Apr '10

I would like to thank all that contacted me, from all the good advice I have now ordered the proper adapters, they should be hereby the end of his week. Again thanks to all. Dave VA7DG

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SO-50 demo planned for Thursday
by n4csitwo＠bellsouth.net 07 Apr '10

07 Apr '10

Hello all, I will be holding a presentation and SO-50 demo tomorrow Thursday, April 8th for a gifted class at Sleepy Hill Elementary School in Lakeland, FL. I understand that out of 52 students, 12 hold their technician licenses and about 12 more will take their test shortly. I would like to invite anyone who can, to join us for the 15:26 UTC (11:26 ET) pass as max. elevation will only be 9 deg. and this is my only opportunity for a pass due to class times. See you on the bird, Dave, AA4KN an AMSAT area coordinator for Central Florida ARISS Team member LMARS member

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seeking examples of frequency bands used in amateur spacecraft
by Samudra Haque 07 Apr '10

07 Apr '10

Hello with reference to the US FCC Part 97 and in particular section 97.207 "Space Station" available http://www.arrl.org/FandES/field/regulations/news/part97/c.html#207 Have all of the frequency bands listed below been used in service through the last four decades? The following frequency bands and segments are authorized to space stations: (1) The 17 m, 15 m, 12 m and 10 m bands, 6 mm, 4 mm, 2 mm and 1 mm bands; and (2) The 7.0-7.1 MHz, 14.00-14.25 MHz, 144-146 MHz, 435-438 MHz, 1260-1270 MHz and 2400-2450 MHz, 3.40-3.41 GHz, 5.83-5.85 GHz, 10.45-10.50 GHz and 24.00-24.05 GHz segments. What power limitations are stipulated for these bands? Samudra, N3RDX & S21X Alexandria, VA

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Re: AO-7 Mode C? (Or other reason for varying signal strength?)
by Bob- W7LRD 07 Apr '10

07 Apr '10

I also have noticed similar events with AO-7. I try to work into Northern Europe when the opportunity is there. As you mentioned, polarization, obstructions, local noise. I might add just being a bit temperamental at being up there for 35 years! I find it remarkable that we are privileged to have access to such a marvelous bucket of bolts. 73 Bob W7LRD Seattle ----- Original Message ----- From: "Bill Dzurilla" <billdz.geo(a)yahoo.com> To: amsat-bb(a)amsat.org Sent: Tuesday, April 6, 2010 8:07:38 PM GMT -08:00 US/Canada Pacific Subject: [amsat-bb] Re: AO-7 Mode C? (Or other reason for varying signal strength?) So, folks, does anyone have any thoughts or comments about this issue? 73, Bill NZ5N --- On Sun, 4/4/10, Bill Dzurilla <billdz.geo(a)yahoo.com> wrote: From: Bill Dzurilla <billdz.geo(a)yahoo.com> Subject: AO-7 Mode C? (Or other reason for varying signal strength?) To: amsat-bb(a)amsat.org Date: Sunday, April 4, 2010, 10:52 PM Hi folks, Since starting my effort to work Europe on AO-7, I've found that the very low elevation sigs vary significantly on different passes. Some mornings I can easily hear my downlink and start working Europe at 0.7 degrees elevation, while other days I can't hear myself until 5 degrees elevation, after the window to Europe has closed. Not sure if this is due to band conditions, satellite polarization, obstructions at certain positions, operator error, local noise, or what. Today I spoke with another experienced AO-7 op and he had an interesting theory: on the bad days (when I don't hear my downlink until 5 degress), the sat is in Mode C (lower power). This seems to make sense, because there does not seem to be any middle ground -- I start hearing my downlink at either 0.7 degrees or 5 degrees, never at 2-4 degrees. Anyone have any thoughts on this? Are we able to predict when the sat will be in one mode or another? Or any other explanation for the signal strength variations? 73, Bill NZ5N _______________________________________________ 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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Re: seeking examples of frequency bands used in amateur spacecraft
by Samudra Haque 07 Apr '10

07 Apr '10

Thank you for the information - I am getting now interested in this area to research what type of modes were used to communicate and the observed/reported characteristics of operation in those bands. Might come in handy when choosing subsystems to fly on future nano-satellites/pico-satellites. Thank you also: Arthur and John for your detailed replies. 73 -samudra On Tue, Apr 6, 2010 at 8:10 PM, David Giles <vk5dg(a)amsat.org> wrote: > Hello Samudra, > Here's some examples of OSCARS and RS-series that have used the bands (or > at least flown transmitters/receivers to do so) > 40m - UO-09 > 20m - UO-09 > 15m - UO-09, RS-12/13 > 10m - plenty including AO-7,AO-51 > 3.4GHz - none to my knowledge > 5.8GHz - AO-40 receive, P3-E transmit (proposed) > 10GHz - AO-40 (didn't work) > 24GHz - AO-40 (heard this one in operation) > > Hope this helps. > > 73 de David VK5DG > >

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Re: seeking examples of frequency bands used in amateur spacecraft
by Arthur Feller 06 Apr '10

06 Apr '10

Hi, Samudra! The last major change in frequency allocations to the amateur-satellite service came from the 1979 General World Administrative Radio Conference. Domestically, the changes became "official" upon the consent of the US Senate. Suggest reading the paper on "Amateur Satellites" on the IARU web site and looking at the Annex with the frequency allocations. AO-40 attempted to use most of the UHF and SHF bands. No power limit is specified in the RR's. At the same time, the principle of using the minimum power necessary still applies. I hope this helps. 73, art..... W4ART Arlington VA afeller(a)ieee.org Apr 6, 2010 03:21:25 PM, samudra.haque(a)gmail.com wrote: =========================================== Hello with reference to the US FCC Part 97 and in particular section 97.207 "Space Station" available http://www.arrl.org/FandES/field/regulations/news/part97/c.html#207 Have all of the frequency bands listed below been used in service through the last four decades? The following frequency bands and segments are authorized to space stations: (1) The 17 m, 15 m, 12 m and 10 m bands, 6 mm, 4 mm, 2 mm and 1 mm bands; and (2) The 7.0-7.1 MHz, 14.00-14.25 MHz, 144-146 MHz, 435-438 MHz, 1260-1270 MHz and 2400-2450 MHz, 3.40-3.41 GHz, 5.83-5.85 GHz, 10.45-10.50 GHz and 24.00-24.05 GHz segments. What power limitations are stipulated for these bands? Samudra, N3RDX & S21X Alexandria, VA _______________________________________________ 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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