【AFアンプで五極管を・第3回】 introduction I have many pentodes for RF. This blog is a continuation of the previous one. This time I will build an audio amplifier with pentodes for RF with 7-pin mt tubes. Hopefully I can expand the use of those pentodes. I tested three types of pentodes: 6CB6, 6AK5, and 19M-R10. The 19M-R10 is an original Japanese tube made for NTT's telephone relay network. All of the

【AFアンプで五極管を・第2回】 introduction I have a lot of pentodes for RF.　In this blog I will build an audio amplifier with 9-pin NOVAL based pentodes for RF. If they can be used well, they will expand their applications.　I tried three different types: 6BX6, 6EJ7 and E180F. They all seem to work well enough for audio amplifiers. They are very high gain and should be used with care. hi hi (2024.06.06 de

【40mバンドのホイップ・アンテナを作る】 abstract I have built a 40m Band Whip Antenna. This antenna is designed to enjoy HAM by carrying a radio station in a car and moving it around. This antenna has the same structure as the 30 m band antenna introduced in two previous Blogs. Of course, the resonant frequency is different. The construction was easy as I used some parts specially designed for whip antennas. The

【AFアンプで五極管を】 introduction The pentode tube is a vacuum tube created from the improvement of the triode. The pentode is improved high-frequency amplification characteristics and power supply voltage utilization ratio of the triode. In addition, the pentode has a large transconductance, which allows for a large amplification gain.　Therefore, for the same supply voltage, a much higher gain and

【14MHzと18MHzの２バンド・ホイップ・アンテナ】 abstract I built a duo-band antenna for 14 MHz and 18 MHz. But the performance of that antenna was poor. The RF Power radiation efficiency was not good.　The reason was the stainless steel antenna element.　The antenna was a shortened version with a loading coil. The presence of stainless steel in the magnetic field of the coil caused a loss of RF power.　I was able to

【アンテナ・チューナの整備と研究】 abstract I am repairing a Yaesu Musen FC-700 antenna tuner. I have been using this antenna tuner for a long time. It seems that the contacts of the switch have oxidized due to years of use. It will be possible to repair it by cleaning the contacts of the switch. And I will use this repair opportunity to study the inside of the FC-700. I have also considered several antenna

【デジタル・モード・トランシーバ：ADX-S製作】 abstract The ADX-S is a modification by BD2CR Adam Rong of the ADX digital mode shortwave transceiver developed by WB2CBA Barbaros Asuroglu.　Both software and hardware are open source and information is available on GitHub.　He referred to my Blog article when he improved the ADX-S. I was wondering what part of my Blog he referred to. I contacted the distributor, JL1KRA

【30mバンドのホイップ・アンテナを作る】 abstract The 30m band is a new HAM band in Japan; it has been authorised since 1 April 1982.　Only HAMs with an advanced licence can on-air in the 30 m band.　Therefore, few HAM stations on the air are available, so existing antennas are limited. High performance 30m band antennas for mobile use are unlikely.　If not, it is best to build your own. I build high efficiency 30m

【パークス・オンジエア：公園からオンジエア】 abstract Have you heard of POTA?　POTA stands for "Parks on the Air" and is an on-air activity of HAM stations from the parks.　It is a US-derived activity derived from Summit on the Air (SOTA). POTA has already become a worldwide activity.　You can easily get started. The first step is for you to become a 'Hunter'. Then, once you have registered an account on the POTA

【自動車無線と車載アンテナの話】 abstract Modern vehicles are more aerodynamic in character. It has become more difficult to mount HAM antennas in such vehicles. This Blog explains how to find and mount the antenna where it can be installed. Modern cars can also be used to enjoy amateur radio. (2024.01.11 de JA9TTT/1 Takahiro Kato)　 【アンテナが付くクルマ】 　『今どきのクルマにアンテナなんて付かないよ』アキバのHAMショップで店員に冷たくそう言われてしまいました。 　最近の車に向いた（