さて、TDXCメンバーとオンラインで飲みながら話をしていると、アマチュア無線やBCLの屋外での活動が話題になり、最近ブームになっているカーボンロッドアンテナの話題も提供され、わいわいと盛り上がりました。私も昨年くらいから、コロナ禍で屋外に出ることができないストレスもあってか、ノイズの少ない森や原っぱで自作のアンテナ等を張って、お弁当や昼ビール（昼ビー）でもしながら、SDR等を使って中波、短波、FMを受信してみたいなあと思うようになりました。もともと中波DXpedtionで大自然の中での受信がもともと好きでしたし、アマチュア無線の世界でも山の上からのオンエアであるSOTA(Summits On The Air）や、公園からのオンエアPOTA(Parks On The Air)が行われており、Youtube等でその様子を見るにつけ、なかなかいいものだなあと思うようになったことも理由になります。
K6ARK アダムさんのYoutube "K6ARK Portable Radio"より
特に言葉にこだわるつもりはないのですが、BCL（BroadCasting Listening)から、屋外に飛び出ての受信ということで、FRL（Field Radio Listening)あるいは、だいぶ前に、Filed Listening という言葉から受ける語感については、カナダ人の友人に聞いてみたところ、「そうだね、まず頭に浮かんだのは、誰かが科学的な研究のために街から離れた屋外に何かを聞きに行くというイメージだね。」ということだったので、FRL（Field Radio Listening ）という言葉は結構いい感じなのかもしれないなと思っているところです。
I attended the Zoom Fest (NASWA Winter SWL Fest) of international radio hobbyists from 3 a.m. on March 6. Before 9 a.m., one of my Japanese radio hobbyist friends gave a presentation about the situation of BCL in Japan in good English. My pictures were also included in the presentation materials. I think there were over 140 participants, but only 5-6 were from Japan. I also participated in this Fest last year.
The Western participants, who seemed to be around the same age as me, talked loudly in English. Sometimes I had to turn down the volume of my PC because the speakers spoke so loudly among their conversations. Questions were frequently asked, and all the presentations were lively beyond a certain level. I felt that this kind of interaction was a quintessential part of the event, as it was last year. Although they were speaking in English, I could almost follow the content because it was about radio hobby. It was not like I had already seen the presentation before. I was also able to learn some fresh information that I wanted to know about. Presenters showed us pictures of their receivers and the rooms (shacks) where they had them all lined up, which made me grin and wonder if some of their wives were frowning.
I will definitely attend this Fest again next year.
Over the consecutive holidays of January 9-10, Radio Siesta-san, Shinzo-san, Hanabusa-san (These are their nicknames.), and I conducted a medium wave DXpedition at a villa with a large garden facing the Pacific Ocean in the Boso Peninsula, Chiba Prefecture. The day was blessed with good conditions and we received many Australian MW stations. This time, We set up a 20-meter-long delta loop antenna array which I deployed in November last year. The antenna was directed to South. We enjoyed MW DX reception from late Sunday night on Jan.9 to early Monday morning on Jan.10.
We met at Kawasaki station and headed for the site by a car driven by Hanabusa-san. On the way, we stopped for lunch at Kamome Shokudo (Kamome Restaurant) in Kisarazu City, where we had conger eel tempura（Fried conger eel) rice bowls. Needless to say, the portion was huge. So it was hard to reach for the meals at the supermarket where we stopped to buy our midnight snacks because we were full after eating the conger eel tempura rice bowl.
穴子天丼：Fried Anago(Conger eel) rice bowl(Click to enlarge)
Upon arrival, we immediately started setting up the antenna. The antenna we set up in the south direction was the aforementioned 20-meter-long delta loop antenna array. This antenna is made by placing two loop antennas in a straight line, changing the phase of the signal between both feed points by 180 degrees, and then adjusting the phase of the loop antenna in the direction where we want a null pattern. For the phase adjustment, I used about 15 meters of 50 ohm coaxial cable. A transimpedance amplifier using LMH6702 is mounted in both feed section to convert the current induced in the loop antenna into voltage. By using this amplifier, a flat antenna gain characteristic in the band is realized.
System diagram of the delta loop antenna array （Click to enlarge）
Antenna Pattern (Vertical Pol. @1MHz)
Installation of the delta loop antenna array(Click to enlarge)
DC distribution box, 50ohm power combiner, delay line and CMC (Click to enlarge)
The cottage we used this time has a solar power system on the roof, and the control panel of the power combiner showed that it was working during the daytime. Unfortunately, during the daytime, the noise from the power combiner of the solar power generator was so strong that we could hear a noise like a cry of Chinese muntjac all over MW band. I wanted to turn off the power combiner, but I couldn't contact with the owner of this rental villa at that time. However, as soon as the sun went down, the noise completely disappeared, and after that, we could only hear a light electric static noise, almost free from artificial electric noise. This was an ideal situation for MW DX. I've been DXing in many different places, but it's hard to experience such a quiet noise environment.
Now, I would like to share you my reception logs. Since I am not familiar with Chinese or Southeast Asian languages at all, I specialized in logging English stations. I was able to hear 79 English stations, excluding AFN in Japan. It is truly an extraordinary situation to hear so many English stations like this and I think it is the best part of MW DX. The log can be downloaded fromhere(click)
Now, I would like you to listen to several actual reception sounds. Some of you may not be familiar with MW DX, so please put on your headphones and experience what we were receiving. I hope you can feel the extraordinary nature of MW radio waves propagating from thousands of kilometers away. I chose audio clips that is relatively easy to listen to. Enjoy!
（1）ABC 4QD 1548kHz, 50kW Emerald, QLD, Australia at 16:00UTC on Jan.10
This is a familiar regular station in Queensland of Australia that can be received in MW DXpedition. It is possible to receive this station inland, but it is rarely heard this well. If you have an antenna with a large gain, a low noise environment, and a receiver with excellent dynamic range you can receive this station as if it were a local station.
（2）ABC 8GO 990kHz, 0.5kW Nhulunbuy, NT, Australia at 16:00UTC on Jan.10
この局は、私は初受信でした。オーストラリア、ノーザン・テリトリーのヌランベイにあるABCのラジオ局です。同地区ダーウィン向けの放送を行っています。出力は0.5kWと小さく、珍しい局の部類に入るのではないかと思っています。IDは、”ABC radio Darwin"と出ています。0.5kWという低出力にも関わらず良好に受信できたことに驚いています。
This was the first time for me to receive this station. It is an ABC radio station in Northern Territory, Australia. I guess this station is rare to be received due to 0.5kW of low output power. The ID is "ABC radio Darwin". The ID is "ABC radio Darwin". I was surprised that I could get good reception in spite of 0.5kW of low output power.
（3） 5CS 1044kHz, 2kW Huddleston, SA, Australia at 17:58UTC on Jan.10
This was also my first time to receive this station. It is a commercial radio station in Huddleston in South Australia, Australia. The ID is "Classic Hits 5CS".
（4） 4BH 1116kHz, 17kW Brisbane, QLD, Australia at 18:00UTC on Jan.10
The ID is "Brisbane, 4BH" with music. This is a commercial radio station in Brisbane in Queensland state. The signal is not strong, but it is clearly audible because there is little external noise. Please try to feel how little external noise there is. I'm sure it's not like this at your home. The noise that comes right after the ID, is the noise of lightning over the Pacific Ocean.
（5） 3MP 1377kHz, 5kW Melbourne, VIC, Australia at 16:59UTC on Jan.10
ビクトリア州メルボルンの民放ラジオ局です。IDはチャイム音の後に"3MP, proud to be Ace Radio Network" と出ています。
This is a commercial radio station in Melbourne, New South Wales, and its ID is "3MP, proud to be Ace Radio Network" after the chime.
（6） Radio TAB 1539kHz, 10kW Adelaide, SA, Australia at 17:00UTC on Jan.10
This station in Adelaide, South Australia, is run by the Totalisator Agency Board and broadcasts horse and greyhound racing (so-called dog racing). On this day, This station was confirmed on 1242 kHz too . There is no ID in the audio clip, but at 18:00UTC, I could hear an ID "Radio TAB" in the weak signal. The announcer spoke something about Crystal Water in this clip, which seems to be the name of a horse. Please listen to the background female voice on the top, which is small but so clear too.
（7） 2QN 1521kHz, 10kW Deniliquin, NSW, Australia at 18:19UTC on Jan.10
オーストラリア、ニューサースウェールズ州、デニリクインの民放局です。IDは、"This is the Australia ... on 15-21 2QN"と出ています。少し信号は弱いのでヘッドフォンで聴いてみてください。
This is a commercial television station in Deniliquin, New South Wales, Australia. The ID is "This is the Australia ... on 15-21 2QN". The signal is a little bit weak, so try listening with your headphones.
（8） 2MM 1656kHz, 0.4kW Darwin, NT, Australia at 17:35UTC on Jan.10
This is a narrowcasting station in Darwin, Northern Territory, Australia. The transmitting power of this station is 0.4kW. The language spoken in this program seems to be Greek, not English. The ID is "2MM (Two double M)" with music.
（9） 3SH 1332kHz, 2kW Swan Hill, VIC, Australia at 18:00UTC on Jan.10
This is a commercial TV station in Swan Hill, New South Wales, Australia. The ID is "13-32 3SH". During this time, the lightning noise over the Pacific ocean was terrible. But the signal was still coming through.
（10） Hot Country 1629kHz, 0.4kW Darby, QLD, Australia at 16:59UTC on Jan.10
オーストラリア、クイーンズランド州のダルビーにあるナローキャストを実施している放送局です。出力は0.4KWです。IDは陽気な声で”Saturday morning talk show 9a.m..., Hot Country”と出ています。
This is a narrowcasting station in Dalby, Queensland, Australia. The ID is "Saturday morning talk show 9a.m., Hot Country" in a cheerful voice. The ID is "Saturday morning talk show 9a.m. ... ,Hot Country" in a cheerful voice.
The official frequency of this station is 1629 kHz, but there was clearly an offset, meaning the frequency was out of 1629kHz a little bit. I think the frequency offset was about minus 50 Hz.
Cross Country Wireless(CCW)のループアンテナ用プリアンプLAA++はちょっと気になりました。性能について記載されていますが、出力でのインターセプトポイントの値が記載されており、これをどう読むかはピンときませんでした。入力でのインターセプトポイントの値も知りたかった（換算できるのでしょうか？）。また14MHzでの利得が25dB、そして雑音指数が0.79dBとありましたが、本当にこんなに小さい雑音指数が達成できているのか？とちょっと疑いの眼で見ているところです。
また、さらには、海外の視聴者モニター達とのやり取りも、 アップルのニュートンというメッセージパッドとモデムを使ってコンピューター通信でできるようにし、1991年にソ連が崩壊した後には、VOAはRadio Free Europe とRadio Liberty ののネットワークと中継局、前ソ連に在住していた多くの聴取者モニターを受け継ぎ、このモニター達にサンクトペテルブルグの会合でこのニュートンによる新システムの紹介をしたっていうんですから、このウィトカー氏を始めとするVOAの実行力・機動力は恐るべしですね。
