January 2008 - AMSAT-BB - mailman.amsat.org

WAS Re: AO-16 report from Copenhagen
by Mark L. Hammond 27 Jan '08

27 Jan '08

Hello Francesco, The 437.024 transmitter antenna configuration on AO-16 is Left Hand Circular polarity (LHCP). The receiving antenna on the bird is a 1/4 wave vertical whip. The fading is quite dramatic, which means the bird is spinning/tumbling, or some combination. We could never hear this before on AO-16 when it was transmitting its normal PSK signal, since we didn't hear the effect of fading on the uplink in this mode. Now we hear it, loud and clear! It does take an uplink signal that is pretty close to on frequency (145.820). Adjusting for Doppler is helpful thing on the uplink. Doppler on the 435 DSB downlink will make you love (or covet) a computer controlled VFO :) It's so much fun to be a part of this NOW, on AO-16's 18th birthday---I vividly recall the launch and commissioning 18 years ago---THANKS to the folks that put them all together and got them in the air!! 73, Mark N8MH AO-16 Command Team >Hello, >I tried AO-16 too on one pass, noise level is high and also I noticed >a very deep fading I could not compensate with H/V polarity switch. >This is the only LEO I ever found difficult to access so far, I'm >going to test other known sat to check my setup, maybe the problem is >only here. >I also found difficult to tune some stations, the audio never come >good as if the modulation was distorted, I don't know if others had >the same results. I've never had problems with linear sats however. >I'll try again tomorrow. > >73 >Francesco IZ8DWF Mark L. Hammond [N8MH]

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AO-16 Downlink
by Clint Bradford 27 Jan '08

27 Jan '08

>>...Mode FM Voice Repeater (Downlink is double sideband.) Hmmm...Isn't "double sideband" AM? Amplitude modulation of a carrier wave normally results in two mirror-image sidebands... How should I program my FT-817 for the downlink? Embarassingly yours, Clint, K6LCS

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AO-7 DX
by w7lrd＠comcast.net 27 Jan '08

27 Jan '08

Hello The next pass of AO-7, at 2127Z (in one hour) I will have a path to Northern Europe. I will be on 145.952 looking for DX especially OH8MBN. 73 Bob W7LRD -- "if this were easy, everyone would be doing it"

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Re: WAS Re: AO-16 report from Copenhagen
by Tom Clark, K3IO 27 Jan '08

27 Jan '08

Mark, N8MH noted: > The 437.024 transmitter antenna configuration on AO-16 is Left Hand Circular > polarity (LHCP). The receiving antenna on the bird is a 1/4 wave vertical > whip. > This whip operates against the body of the spacecraft as a "ground plane"; however the spacecraft body is a cube 22 cm on a side (you can see a picture at http://128.54.16.15/amsat-new/satellites/satInfo.php?satID=11&retURL=/satel… <http://128.54.16.15/amsat-new/satellites/satInfo.php?satID=11&retURL=/satel…>). This is about half of the quarter-wavelength you'd like to see for a proper ground reference, so the actual pattern undoubtedly has some weird nulls. > The fading is quite dramatic, which means the bird is spinning/tumbling, or > some combination. We could never hear this before on AO-16 when it was > transmitting its normal PSK signal, since we didn't hear the effect of fading > on the uplink in this mode. Now we hear it, loud and clear! > > It does take an uplink signal that is pretty close to on frequency (145.820). > Adjusting for Doppler is helpful thing on the uplink. > The receiver has a 15 kHz wide crystal filter with sharp skirts. So if your NBFM xmtr is set with a ±5 kHz deviation, you may well find your signal hitting the filter "walls". You may get better performance if you crank the deviation back a bit. 73, Tom

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K3SZH AO7 new record
by Fabio Teixeira Magalhaes 27 Jan '08

27 Jan '08

Dr Joe-K3SZH, congratulations to your mark: 5000 register in ao-7 log. I´m very happy to contribute with your record.......... 73 es DX - Fabio- PY4AJ AMSAT 19748

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AO-07 5000 Contacts
by dcowden＠nc.rr.com 27 Jan '08

27 Jan '08

Congrats on 5000 Contacts in AO-07 Log Joe. I enjoy our QSO's. Have Many more. Don, N8DDK

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Re: Full non-Eclipse time V on time
by Bob Bruninga 27 Jan '08

27 Jan '08

> How long or how many full orbits does it > take to enable these two satellites? > I can see what some days PCSAT is in > full sunlight for 2 or 3 full passes, > would this mean she would come alive > on 1 full pass or does it take more? PCSAT-1 comes alive on every single orbit, every day. But it only has enough power to transmit a full packet when it is in the northern latitudes (around 45 degrees) and then only when it is passing under the sun (near local noon). During this time, on every pass, a few user packets are sucessful. And yes,we can command un-needed loads off easily. But then it goes into eclipse 30 minutes later and the batteries die again. When it comes out of that eclipse, then it takes 15 minutes of sun before it can be heard again. This happens on every orbit, 14 times a day. But on 9 Feb, PCSAT will enter a period of zero eclipses and that is why it will not die and we can use it for a few weeks. Bob, Wb4APR And what about UO11, as Clive said this is due to go into eclipse for months in March onwards, but surely some days it should hit full sunlight for a few hours? Also, does instantrack show the eclipse and non eclipse periods on a

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AMSAT Web Updates
by JoAnne Maenpaa 27 Jan '08

27 Jan '08

Hello Everyone, The http://www.amsat.org main page has been updated with the good news of the AO-16 recovery. Scroll down the page, it will be the second headline item on the front page. This weeks ANS bulletins are also available at http://www.amsat.org/amsat-new/news/ in case you are away from e-mail or have problems reading the message. -- 73 de JoAnne K9JKM k9jkm(a)amsat.org

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5000 on AO-7, K3SZH.
by TERRY BROMLEY 27 Jan '08

27 Jan '08

Joe congratulation's in reaching 5000 in ao-7 log. You keep me company most day's, i thank you for that my friend. 73. Terry G1WPR.

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Full non-Eclipse time V on time
by Chris Bloy 27 Jan '08

27 Jan '08

Hi All, This is a question for Bob and Clive about UO-11 and PCSAT. How long or how many full orbits does it take to enable these two satellites? I can see what some days PCSAT is in full sunlight for 2 or 3 full passes, would this mean she would come alive on 1 full pass or does it take more? And what about UO11, as Clive said this is due to go into eclipse for months in March onwards, but surely some days it should hit full sunlight for a few hours? Also, does instantrack show the eclipse and non eclipse periods on a chart? Thanks, Chris

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