On 27 Jun 2009 at 22:50, Jim Jerzycke wrote:

Hi, everybody. Today at Field Day was the first time I tried to work AO-27, and succeeded. One thing I noticed, is that as the satellite came up over the horizon, I wasn't hearing anything until what sounded like a long data burst happened. Then I heard the sat come alive, with what sounded like people already in QSO. As the sat progressed, I heard a lot of operators, then the long data burst happened again, and it seemed like the sat went "dead" I know a bit about how it's scheduled (TOPR), but since this is the first time I was able to hear it well enough to actually consider it usable. What's the data burst? Is it part of the TOPR, or am I hearing something else? 73, Jim  KQ6EA

AO-27 alternate between analog and telemetry date session see below and check their web site at http://www.ao27.org/AO27/index.shtml

Current Time UTC => Sun Jun 28 10:58:47 2009 Schedule Time => 00:51:32 Current State => 7 Mode => OFF Remaining => 00:49:16

Next Event UTC => Sun Jun 28 11:48:03 2009 State => 0 Mode => Digital Med

TOPR Epoch (UTC) = Sat Jun 13 18:58:13 2009 TOPR Epoch (ctime) = 1244919493 Schedule Period (sec) = 6048.524

State Start Time End Time Duration(sec) Mode -------------------------------------------------------- 0 00:00:00 00:00:20 20 Digital Med 1 00:00:20 00:07:20 420 Analogue Med 2 00:07:20 00:08:20 60 Digital Med 3 00:08:20 00:32:01 1421 OFF 4 00:32:01 00:33:01 60 OFF 5 00:33:01 00:33:21 20 OFF 6 00:33:21 00:33:41 20 OFF 7 00:33:41 01:40:48 4027 OFF

"-"

Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE

Hi Jim,

Interesting... That was probably the pass I was trying to work AO-27 too, but I didn't have any success at all. All I got back was hash, with others audible below it. I think my uplink was interfering my downlink locally, though it went away after the pass. Gotta work on that.

But, in answer to your question, the satellite has a scheduled sequence that it goes through. There's a program to predict when the different phases are going to kick in, downloadable from http://sites.google.com/site/ao27satellitescheduler/ and it shows exactly what you and I experienced during the pass. I suspect it appeared like the satellite turned on with conversations already in progress because they jumped the gun a bit on the uplink, or weren't aware of the timer and were transmitting without being able to hear anything. The digital parts of the pass are telemetry, and you can decode and contribute what you hear to the archive. The main page is http://www.ao27.org.

Enjoy,

Greg KO6TH

Date: Sat, 27 Jun 2009 22:50:49 -0700 From: kq6ea@pacbell.net To: amsat-bb@amsat.org Subject: [amsat-bb] AO-27 Question

Hi, everybody. Today at Field Day was the first time I tried to work AO-27, and succeeded. One thing I noticed, is that as the satellite came up over the horizon, I wasn't hearing anything until what sounded like a long data burst happened. Then I heard the sat come alive, with what sounded like people already in QSO. As the sat progressed, I heard a lot of operators, then the long data burst happened again, and it seemed like the sat went "dead" I know a bit about how it's scheduled (TOPR), but since this is the first time I was able to hear it well enough to actually consider it usable. What's the data burst? Is it part of the TOPR, or am I hearing something else? 73, Jim KQ6EA _______________________________________________ Sent via AMSAT-BB@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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