ダイポール・アンテナとダブレット・アンテナ （その２） [Antenna]
ダイポール・アンテナとダブレット・アンテナ、その２です。
気になったので手持ちの本を幾つか見てみました。
まず、古い本の方から
The radio amateur's handbook 32ND EDITION 1955
CHAPTER 14 Antennas
The Half-Wave Antenna
The fundamental form of antenna is a single wire whose length is approximately equal to half the transmitting wavelength. It is the unit from which many more-complex forms of antennas are constructed. It is known as a dipole or Hertz antenna.
～以下省略～
と書かれています。半波長に共振しているアンテナをダイポールもしくはヘルツ・アンテナとしています。
Multiband Antennas
Simple Systems
The most practical simple multiband antenna is one that is a half-wavelength long at the lowest frequency and is fed either at the center or one end with an open-wire line.
～以下省略～
Antennas for Restricted Space
If the space available for the antenna is not large enough to accommodate the length necessary for a half-wave at the lowest frequency to be used, quite satisfactory operation can be secured by using a shorter antenna and making up the missing length in the feeder system. The antenna itself may be as short as a quarter wavelength and still radiate fairly well, although of course it will not be as effective as one a half-wave long. Nevertheless, such a system is useful where operation on the desired band otherwise would be impossible.
Tuned feeders are a practical necessity with such an antenna system, and a center-fed antenna will give best all-around performance.
～以下省略～
フィードラインを含めて共振させてマルチバンド対応にするアンテナの紹介がありますが、ダブレットの表記はありません。
1980 THE RADIO AMATEUR'S HANDBOOK
Chapter 20 Antennas for High Frequency
The Half-Wave Wavelength Antenna
The fundamental form of antenna is a single wire whose length is approximately equal to half the transmitting wavelength. It is the unit from which many more-complex forms of antennas are constructed. It is known as a dipole.
～以下省略～
1955年版に比べて Hertz antenna の記述が無くなっています。
さらにMultiband Antennas の記述は無くなり、マルチバンドに関してはトラップ・ダイポールが紹介されているだけです。
ARRL's Wire Antenna Classics
Volume 1 には G5RV アンテナが紹介されていますが、ダイポールとは書かれていません。
Volume 2、3 では、オープンワイヤーでフィードする記事が少なく、ダイポール表記になっています。
QST に載っている宣伝では割と G5RV 等が出ているのですが、記事は Voleme が進むにつれて減ってきている感じがします。
で、極めつけはこれで、そのものずばりが出ていました。
THE ARRL ANTENNA BOOK
FOR RADIO COMMUNICATIONS
22nd EDITION (2011)
P. 9-2
Dipole or Doublet?
When does a dipole become a doublet and vice versa? There is no formal difference - these are just two different names for the same antenna. The term "doublet" is often applied to symmetrical center-fed antennas that are not resonant or that are used on multiple bands to distinguish them from the resonant center-fed dipole. This is a matter of convention only.
"Dipole" means "two poles" with the poles being the out-of-phase voltages on either side of the dipole. From the Wikipedia entry (en.wikipedia.org/wiki/Dipole) "An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some (usually small) distance."
The antenna feed line supplies voltages with opposite polarity on either side of the feed point, crating the pair of electric poles. The poles cause current to flow in the antenna, creating the radiation. As the length increases beyond a half-wavelength, the situation is much less clear because multiple poles eventually appear. For example, a 3/2-wavelength wire is really a tri-pole.
う～ん、ARRL と RSGB ではとらえ方が違いそうな気がします。
気になったので手持ちの本を幾つか見てみました。
まず、古い本の方から
The radio amateur's handbook 32ND EDITION 1955
CHAPTER 14 Antennas
The Half-Wave Antenna
The fundamental form of antenna is a single wire whose length is approximately equal to half the transmitting wavelength. It is the unit from which many more-complex forms of antennas are constructed. It is known as a dipole or Hertz antenna.
～以下省略～
と書かれています。半波長に共振しているアンテナをダイポールもしくはヘルツ・アンテナとしています。
Multiband Antennas
Simple Systems
The most practical simple multiband antenna is one that is a half-wavelength long at the lowest frequency and is fed either at the center or one end with an open-wire line.
～以下省略～
Antennas for Restricted Space
If the space available for the antenna is not large enough to accommodate the length necessary for a half-wave at the lowest frequency to be used, quite satisfactory operation can be secured by using a shorter antenna and making up the missing length in the feeder system. The antenna itself may be as short as a quarter wavelength and still radiate fairly well, although of course it will not be as effective as one a half-wave long. Nevertheless, such a system is useful where operation on the desired band otherwise would be impossible.
Tuned feeders are a practical necessity with such an antenna system, and a center-fed antenna will give best all-around performance.
～以下省略～
フィードラインを含めて共振させてマルチバンド対応にするアンテナの紹介がありますが、ダブレットの表記はありません。
1980 THE RADIO AMATEUR'S HANDBOOK
Chapter 20 Antennas for High Frequency
The Half-Wave Wavelength Antenna
The fundamental form of antenna is a single wire whose length is approximately equal to half the transmitting wavelength. It is the unit from which many more-complex forms of antennas are constructed. It is known as a dipole.
～以下省略～
1955年版に比べて Hertz antenna の記述が無くなっています。
さらにMultiband Antennas の記述は無くなり、マルチバンドに関してはトラップ・ダイポールが紹介されているだけです。
ARRL's Wire Antenna Classics
Volume 1 には G5RV アンテナが紹介されていますが、ダイポールとは書かれていません。
Volume 2、3 では、オープンワイヤーでフィードする記事が少なく、ダイポール表記になっています。
QST に載っている宣伝では割と G5RV 等が出ているのですが、記事は Voleme が進むにつれて減ってきている感じがします。
で、極めつけはこれで、そのものずばりが出ていました。
THE ARRL ANTENNA BOOK
FOR RADIO COMMUNICATIONS
22nd EDITION (2011)
P. 9-2
Dipole or Doublet?
When does a dipole become a doublet and vice versa? There is no formal difference - these are just two different names for the same antenna. The term "doublet" is often applied to symmetrical center-fed antennas that are not resonant or that are used on multiple bands to distinguish them from the resonant center-fed dipole. This is a matter of convention only.
"Dipole" means "two poles" with the poles being the out-of-phase voltages on either side of the dipole. From the Wikipedia entry (en.wikipedia.org/wiki/Dipole) "An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some (usually small) distance."
The antenna feed line supplies voltages with opposite polarity on either side of the feed point, crating the pair of electric poles. The poles cause current to flow in the antenna, creating the radiation. As the length increases beyond a half-wavelength, the situation is much less clear because multiple poles eventually appear. For example, a 3/2-wavelength wire is really a tri-pole.
う～ん、ARRL と RSGB ではとらえ方が違いそうな気がします。
コメント 0