007: 10GHz EME reception

 カナダのオンタリオ州、アルゴンキンにある46mパラボラアンテナで10GHzのテストをやると聞き、千載一遇のチャンスが到来したと思った。この46m鏡はX bandで利得72dBi、電力半値幅は0.046°という鋭利なビームを持つ。「月の視直径(0.5°)の1/10となる正にピンポイントビームで月を照射したらどんな効果が得られるか」、というアカデミックかつアマチュアライクな好奇心が彼らの動機となり、その実行が主テーマになっているらしい。一方私にとっては全くそれ以前の、自作機器がちゃんと動作するか、そして10GHz EMEを聞くことができるか?が興味のポイント。だからVE3ONTの様なレーダー方程式による単純計算(月面を一様照射する前提)では25dB以上のS/Nで聞こえるハズの巨大局の出現は、逃すことの許されないビッグチャンスであった。私のアンテナシステムはテンポラリーなものだったし、受信機も製作以来熱雑音以外の通信信号は受けたことのないバージン状態だったから確たる自信はなかった。しかし当日は一種の競技会に参加するノリで少なからず緊張しながら受信に挑んだと思う。
 結果的に先ずフェニックスのWA7CJOのテストエコーを捉え(8月19日17:25 UTC、日本時間8月20日02:25 AM)、翌日にはVE3ONTとWA7CJOの両者を受信することができた。この詳細はマイクロ波EME同好会編の「10GHz EME」に記してあるので、機会があれば参照されたい。アマチュア無線の読み物としても面白いと思う。鳥取・淀江グループとともにあの時10GHz受信に挑戦し、両者ともに成功した喜びと達成感。WA7CJOのドプラースミアの大きなビャービャーと鳴るCWエコー、そして対照的にピーピーと清らかに鳴るVE3ONTのエコー。これが当日の記憶として今もハッキリ残っている。日付は1995年8月19日と20日である。


I thought an ideal chance came for me to hear the news that an EME test of 10GHz will be held with the 46m dish in the Algonquin space complex in Ontario, Canada. This 46m dish has a sharp beam of 0.046 degree and 72dBi gain in X band. "If transmitting to the Moon with a pinpoint beam which becomes 1/10 of the apparent diameter of the Moon (0.5 degree), what kind of effect is obtained?" They were motivated by this academic and amateur curiosity, and I heard that the execution was a main theme. On the other hand, it was a point of my interest whether my home brew rig worked well, and 10GHz EME was able to be heard in Japan. The radar equation showed that more than 25dB of S/N will be obtained. (It's the precondition to apply radio wave to the moon surface uniformly.) Therefore, an appearance of this huge station was a big chance which shouldn't be missed. As my antenna system was temporary and the receiver was also in the virgin state which has no experience that a communication signal besides the thermal noise was fed since making, there was no certain confidence that I succeed in the trial. My feeling was the sense to participate in a kind of athletic meeting on the day. I think I challenged to the reception while being not little and becoming tense.

It was luckily possible to catch a test echo of WA7CJO in Phoenix at 17:25UTC on 19, Aug. and received both of VE3ONT and WA7CJO on the next day almost consequently. It was recorded on "10GHz EME" of the microwave EME society volume, so if there is a chance, please refer to these details. I think that's also fascinating as something to read. I challenged 10GHz reception at that time with Tottori Yodoe group (JA4BLC, JR4BRS, JR4AEP, JH3EAO, and JH3ERQ), and there were delight and feeling of achievement in which both of them succeeded. WA7CJO’s CW echo with Doppler smear and an echo of VE3ONT which rings clearly contrastively were striking. This is also left clearly now as the day's memory in my brain. The date is August 19, 20 in 1995.

 

 

 

 

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2017年08月11日