PacSat AO-16 アナログ衛星に再生！
● (No.557) PacSat AO-16 アナログ衛星に再生！ (2008年 1月22日) ------------------------------------------------------------- PacSat 衛星 AO-16 が打ち上げられたのは、1990年 1月22日です。 しばらくの間 運用不能の状態が続いていた このデジタル衛星ですが、誕生日に合わせるかのよ うに、2008年 1月22日、コマンドチームの努力により AO-16 はデジタル衛星から アナログ衛星として生まれ変わりました。アップリンク周波数は 145.920MHz FM, ダウンリンク周波数は 437.026MHz USB です。この広報をした AMSAT-NA 副会長 KO4MA / Andrew Glasbrenner 氏の言葉を紹介します。 Subject: [amsat-bb] AO-16 reconfigured. From: Andrew Glasbrenner Date: Tue, 22 Jan 2008 13:47:42 -0500 Since AO-16 was recovered approximately 6 months ago, the command team has attempted to reload the satellite software almost a dozen times without success. Subsequently a series of memory tests were performed which points towards a hardware failure which prevents restarting the spacecraft software successfully. This team included Bruce Rahn WB9ANQ and Jim White WD0E advising Mark Hammond N8MH as the primary groundstation. Mark put in many early hours during the multiple reloads and test sessions, with Bruce, Jim, and others advising. Thank you to all involved for your hard work. After the conclusion that the spacecraft computer system was damaged and as discussions about decommissioning were taking place, Jim recalled a series of low level commands included in the spacecraft design by Tom Clark, K3IO during construction. One of these commands allows an uplink receiver to be directly tied to a downlink transmitter. The twist is that the uplink is regular FM but the downlink via the BPSK transmitter is DSB (Double Sideband). Mark placed the satellite in this mode early this week and some testing was undertaken. The satellite hears VERY well, and the reduced bandwidth by using either USB or LSB on the groundstation receiver allows for a very robust downlink. Tuning the downlink is just like on a linear transponder, meaning it is tight and with fast Doppler. Uplink tuning is not required, just as with the FM mode V/U satellites. QSOs were made between N8MH, WD4ASW, KO4MA, K5QXJ, and WA6FWF. My personal observations include being able to access and hear the satellite within one degree of the horizon, much lower than any other current bird for my QTH. This should be an easy satellite with omni antennas and a 70cm preamp. With that explanation, I'm happy to open the satellite to general use on voice for a test period. Please submit reports either to the -bb or to ao16@amsat.org . The uplink is 145.920 FM, and the downlink is 437.026 SSB +/- Doppler shift. Please restrict your uplink power to a reasonable level, and do not transmit without being able to hear the downlink. All the general single-channel guidelines apply. Enjoy this bird's new life! 73, Drew KO4MA AMSAT-NA VP Operations http://www.jarl.or.jp/Japanese/2_Joho/2008_news.htm#0124 ----------------------------------------------------------------------- AO-16 は、ご承知のように FM アナログレピーターとして運用が続いています。 先日、管制局代表から下記の現状報告がありました。かいつまんで翻訳します。 今までは全日照が続いていたが、3月下旬から蝕の状態(太陽の当たらない期間) が少しずつ増えてくる。 現在、430帯の少し高めの出力電力を、手動で制限を かける必要があるかもしれない。 利用者から 4月5月6月7月のレポートがある と助かる。テレメトリを取得するために、たまにデジタルモードにするかもし れないが、少しだけのことなのでアナログボイスには迷惑になることは少ない だろう。 S帯は現在運用されておらず、その状態はよくわからない。18年以上 も経つ衛星なので、S帯送信機は現状のままにしておく。 Subject: [amsat-bb] AO-16 status report From: Mark L. Hammond Date: Tue, 4 Mar 2008 11:35:07 -0500 (EST) Hello all, Ronald, I'll take your message as a prompt to provide an AO-16 update! AO-16 is certainly not dead. It is doing quite well in its current mode. Below is the current operational configuration for AO-16: (available from: Sattelite Detail - AMSAT OSCAR 16) Mode FM Voice Repeater (Downlink is double sideband.): Operational Uplink: 145.9200 MHz FM Downlink 437.0260 MHz DSB (LSB and USB) The plan is to continue this mode of voice operations "until further notice." AO-16 has been in full sunlight (no eclipse periods at all) for several months. That is about to change later this month! Short eclipse periods will begin at the end of March and will increase steadily until early July--at which point the eclipse periods will increase to about 26 minutes each orbit. We'll have to watch this old bird and its batteries as the eclipse periods increase. It is possible that the long eclipse periods may necessitate the reduction of the 70 cm transmitter output; this is a manual process for AO-16, since the spacecraft isn't running any housekeeping software to do it "automagically." AO-16 is pretty loud at its current power setting, so some reduction should have little if any user impact. Observations and user reports will be especially helpful during April/May/June/July this year. In order to collect telemetry, we'll need to change the satellite into its digital mode from time to time. But this doesn't take long and therefore shouldn't interfere much with its operations as a voice satellite. The S-band beacon is not operational at this time. The exact status of the S-band transmitter remains unknown; however, its last known status might be described as "suspect" or "semi-operational" at best...(as I recall--and this might not be accurate--there are issues with the power budget, no way to adjust the power output of the S-band transmitter, and so on.) Given the age of the satellite (over 18 years!), my opinion is that this falls into the "maybe we should leave well enough alone for now" category. (And yes, LUSAT/LO-19 is still transmitting CW telemetry on 437.125+/- ----if that's what you mean below?) On behalf of the AO-16 Command Team, -- Mark L. Hammond [N8MH]
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