VHF antennas in radio technology

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  1. Diamond D-130J Discone Antenne
    Diamond D-130J Discone Antenne

    Diamond D-130J Discone Antenne 25 - 1300 MHz

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    Prix à partir de: 139,90 €
    TVA inclus, frais de port non inclus 117,56 €
  2. Antennas Amplifiers Yagi 2m, 8x2 - 14x2 El.; Cross/XPol, Coax
    Antennas Amplifiers Yagi 2m, 8x2 - 14x2 El.; Cross/XPol, Coax

    YU1CF Yagi pour la bande 2m, 8x2 - 14x2 éléments Cross/XPol, deux câbles coaxial séparés

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    Prix à partir de: 310,00 €
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  3. InnovAntennas Yagis LFA monobande 6m
    InnovAntennas Yagis LFA monobande 6m

    Yagis monobandes 50 MHz à faible bruit, 5 - 9 éléments

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    Prix à partir de: 275,00 €
    TVA inclus, frais de port non inclus 231,09 €
  4. Antennes X-Quad 144 et 432 MHz
    Antennes X-Quad 144 et 432 MHz

    Antennes X-Quad pour 144 et 432 MHz, compactes et légères, options de polarisation polyvalentes, idéales pour l'exploitation de satellites.

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    Prix à partir de: 229,00 €
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  5. Diamond X-510N VHF Vertical 2m/70cm
    Diamond X-510N VHF Vertical 2m/70cm

    Diamond X-510N pour 2m,70cm; l=5.2m; N

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    140,90 €
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    REF 16009
  6. Diamond X-50N/X50-NA Omni 2m/70cm
    Diamond X-50N/X50-NA Omni 2m/70cm

    Diamond X-50N/NA pour 2m,70cm; l=1.7m; N

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  7. Diamond X-300 antenne omnidirectionnelle 2m/70cm, PL ou N
    Diamond X-300 antenne omnidirectionnelle 2m/70cm, PL ou N

    Diamond X-300 pour 2m et 70cm ; l=2.9m ; connexion PL ou N

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    Prix à partir de: 106,90 €
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  8. Diamond X-5000 VHF Vertical 2m/70/23cm
    Diamond X-5000 VHF Vertical 2m/70/23cm

    Diamond X-5000 pour 23cm,2m,70cm; l=1.8m; N-connector

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    136,90 €
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    REF 16008
  9. Diamond D-3000 Discône 25-3000MHz (Connecteur N)
    Diamond D-3000 Discône 25-3000MHz (Connecteur N)

    Diamond D-3000 Discône 25-3000M Hz, connecteur N

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    154,90 €
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    REF 18062
  10. PA-1800R Antenne à panneau plat 1800 MHz, 15 dBD
    PA-1800R Antenne à panneau plat 1800 MHz, 15 dBD

    PA-1800R-15 Antenne planaire 1800 MHz 15dBD

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    99,00 €
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    REF 18036.01

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FAQ

Comment regarder la télévision sans antenne ?
Pour regarder la télévision sans antenne classique, vous pouvez utiliser diverses alternatives. Une option consiste à utiliser la télévision par satellite, qui nécessite une antenne parabolique. Une autre option est la réception par câble, à condition qu'une connexion par câble soit disponible dans votre foyer. De plus, vous pouvez regarder la télévision sur Internet, soit via des services de streaming, soit via les médiathèques en ligne des chaînes de télévision. Tout ce dont vous avez besoin est une connexion Internet stable et un appareil de réception approprié tel qu'une télévision intelligente ou un ordinateur avec accès à Internet. Veuillez noter cependant que tous les contenus ne sont pas disponibles gratuitement et que certains services peuvent nécessiter des abonnements ou des frais.
Ivan Leitner
Quelle antenne pour une bonne réception FM ?
Pour une bonne réception FM, une antenne FM spéciale est le meilleur choix. Une bonne option est une antenne de toit extérieure spécialement conçue pour la gamme FM. Celle-ci offre généralement une meilleure qualité de réception que les simples antennes intérieures. Recherchez une antenne avec un gain élevé et un faible bruit, car ces caractéristiques sont cruciales pour une bonne qualité et une bonne force du signal. Si vous vivez dans une zone où les signaux sont faibles ou si vous souhaitez une qualité encore meilleure, vous pouvez également envisager une antenne avec une unité d'amplification. Pour une utilisation mobile ou des pièces plus petites, il existe également des antennes dipôles compactes, faciles à installer et pouvant offrir des performances satisfaisantes. Le choix exact doit également être fait en fonction des conditions locales telles que la distance par rapport à l'émetteur, les sources locales d'interférences et la topographie.
Ivan Leitner
Qu'est-ce que l'UHF et la VHF ?
UHF et VHF sont des gammes de fréquences utilisées en radioamateur. VHF signifie « Very High Frequency » et comprend des fréquences comprises entre 30 MHz et 300 MHz. Cette portée est souvent utilisée pour les communications locales sur des distances plus courtes et dans les zones rurales, car les ondes ont tendance à se déplacer en ligne droite et peuvent être absorbées ou réfléchies par des objets tels que des bâtiments. L'UHF, ou « Ultra Haute Fréquence », comprend les fréquences comprises entre 300 MHz et 3 GHz. Ces fréquences plus élevées ont une longueur d'onde plus courte, permettant une meilleure pénétration des structures urbaines, et sont donc souvent préférées pour les environnements urbains ou pour les communications par satellite. Les deux domaines ont leurs avantages spécifiques et sont utilisés pour diverses applications en radioamateur.
Ivan Leitner

What is the challenge of VHF radio comms?

Range is one of the most important factors in radio communications. VHF range is limited to line-of-sight. This means that there should be an unobstructed line of sight between the transmitter and receiver for contact to be made. The radio link becomes weaker or even impossible if one of the participants is behind an obstacle or behind a mountain or large building. Yet it nevertheless works even for over-the-horizon contacts. But how?

On this page we want to show you the possibilities of VHF radio communications, how you can make contact with other radio operators beyond the (visual) horizon after all, and the importance of choosing the right VHF antenna.

Frequency ranges

The classic VHF bands 2 m and 70 cm carry the largest share of radio operations. The 6- and 4-m-bands and especially the 23-cm-band are rather something for specialists. The frequency range generally referred to as VHF" is divided into the VHF range from 30 MHz to 300 MHz and the UHF range from 300 MHz to 3 GHz. Within these limits are a total of four amateur radio bands:

* Special approval, limited until 31.12.2022

The most important bands on VHF are found in the lower range (from 110 to about 450 MHz). Specifically, these are the bands with approximately 2 m and 70 cm wavelengths. This concerns amateur radio as well as maritime and aeronautical radio and also the public services like police and fire brigade. Of course, there are other frequency bands which are generally referred to as "VHF" and which play a very important role in other areas (cell phones, Wifi, radar, etc.). However, we will not consider these bands here.

Fields of application for VHF antennas

With regard to the possible applications, a distinction is made between mobile radio, i.e. the stationary radio station, either in the car on a boat or plane, or simply the handheld radio; and stationary use, i.e. operation from home with a stationary station.

Mobile radio, i.e. the stationary radio station, either in the car on a boat or plane, or simply the handheld radio

Stationary use, i.e. operation from home with a stationary station.

Distinguishing characteristics of different VHF antennas

Most VHF antenna types can be classified as follows: Omnidirectional antennas are antennas that radiate the transmitter energy equally in all directions, and directional antennas are antennas that have a more or less strong directivity, i.e., they concentrate the radiated energy in one direction only.

Main characteristics of VHF omnidirectional antennas

Antennas with an approximately circular polar pattern in the horizontal plane are called omnidirectional antennas. Vertically polarized omnidirectional antennas are widely used in the commercial sector, such as in the public service sector and for stationary and mobile radio stations. Vertical polarization is also common in amateur radio in the FM range. All FM repeater stations in amateur radio use vertically polarized, mostly omnidirectional antennas. Omnidirectional antennas are offered not only as monoband versions, but also as two- or three-band antennas, for example 2 m, 70 cm and 23 cm.

There are differences in the feed of omnidirectional antennas

  • In its simplest form, a vertically polarized omnidirectional antenna is a ʎ/4 antenna or groundplane antenna for stationary operation. As a so-called "ʎ/4-rod", quarter-wave radiators are often used in mobile operation. The body of the vehicle provides the necessary counterweight.
  • The group of half-wave radiators includes the Sleeve antenna, the J antenna, and the ʎ-5/8 radiator extended beyond the half-wave. Vertical half-wave radiators are mostly end-fed and produce a lower radiation angle and already a slight gain.
  • Only the coaxial dipole is electrically center-fed, although not obvious at first glance.
  • - Last but not least, the family of short helical antennas on handheld radios also includes vertical omnidirectional antennas.

If you arrange two or more vertical omnidirectional antennas stacked on top of each other, you get a collinear antenna. "Collinear" means "arranged in a straight line" on the same axis. Each single radiator is excited in phase via phase lines and must be arranged at a certain distance from each other. As the number of stacked radiators increases, the gain increases and the vertical elevation angle decreases, i.e., the radiation pattern becomes flatter. This design requires a long protecting tube and is also found in amateur radio, but more often in the commercial sector. The popular Diamond "X-nn" antennas are designed this way.

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Main characteristics of VHF directional antennas

A directional antenna consists of at least two elements, the radiator and a passive, radiation-coupled element assigned in the same plane, the reflector. On the antenna boom further elements, the so-called directors, can be arranged in the beam direction in front of the radiator. With the increase of their number, the forward gain of the antenna increases and the aperture angle becomes smaller.

Depending on the horizontal or vertical mounting, directional antennas are horizontally or vertically polarized. The radiation pattern of all directional antennas consists of a large forward lobe and the smallest possible backward lobe. Their characteristics are the (forward) gain and the return loss. When evaluating antennas, a distinction must be made between the isotropic radiator (dBi) (theoretical omnidirectional radiator) and the gain over dipole (dBd). The gain specifications in the technical data for VHF antennas most often refer to the isotropic radiator. The gain specification of the same antenna in dBd, i.e. over the dipole as a comparison antenna, is always 2.15 dB lower. This must be taken into account when comparing antenna data! Another criterion is the horizontal and the vertical beam angle. Logarithmic-periodic array antennas are very suitable when very large frequency ranges without coverage gaps are required. The antenna characteristics are almost constant over the entire operating range. However, in favor of broadband performance, they do not achieve the high gains of Yagi antennas with a smaller bandwith.

Yagi antennas

Not without reason, the Yagi antenna in short or long version is the most frequently used directional antenna in the VHF and UHF range of amateur radio. It is easy and inexpensive to manufacture with a small amount of material. This makes it well suited for do-it-yourself construction. Further advantages are its low wind load and the favorable position of the center of gravity with rotatable arrangement on a rotor. Depending on the concept and the number of elements, a single Yagi antenna achieves a forward gain of about 5 dBd to a maximum of 16 dBd. Beyond that, further extension of the antenna support and the addition of further parasitic elements is no longer useful, because the gain does not increase linearly with increasing antenna length and number of elements, but only in an increasingly flat curve. At about 5 to 6 m antenna length, the limit of mechanical feasibility and stability is reached. A further increase of the gain is then in practice only possible by grouping (stacking) multiple identical antennas. Special forms are cross yagis, directional antennas with elements in square loop form and circularly polarized directional antennas (Helix antennas).

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Characteristics

Which are most important?
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Which antenna for what?

Vertical omnidirectional antennas are preferably used for FM communications - directly or via repeater. In local rounds with participants at different locations spread out in all directions, a directional antenna is of course not so well suited. In this case, an additional omnidirectional antenna is needed. The larger omnidirectional antennas with a little more gain are also suitable to get an overview of the band occupancy in advance in the SSB range under good conditions, in order to switch to a horizontally polarized directional antenna to establish a connection afterwards. Even if one can achieve success with an omnidirectional antenna in SSB under very good propagation conditions, for regular participation in DX operation a powerful yagi antenna that can be rotated by means of a rotor is indispensable. With cross yagis, the polarization plane can be switched between vertical or horizontal, and even in a circular fashion. In FM communications the vertical polarization is common, for SSB, CW and other modes the horizontal polarization. In addition, there are so-called helix antennas, which are directional antennas with circular (i.e. rotating) polarization used in satellite radio.

Mobile radio

Of course, there are also special use cases, such as operation over the moon as a passive reflector (EME, earth-moon-earth), or meteor scatter or satellite operation. All these use cases take place almost exclusively on VHF, in most cases with directional antennas. In contrast to terrestrial radio, circular polarization is often used here. On higher frequencies (from 13cm, 2.4 GHz) often parabolic dish antennas are used as directional antennas, because on the higher frequencies (shorter wavelengths) the size of this design becomes manageable..

Troposcatter
Satellite Radio
Meteorscatter
Earth-Moon-Earth
Aviation radio
Marine Radio

How important is the choice of coaxial cable for VHF antennas??

A good antenna system in the VHF range ultimately requires a higher-quality coaxial cable with low attenuation values. A few meters of RG-58 with PL connectors, will be sufficient for casual operation via the local FM repeater. Longer cable runs and cheap connectors would cancel out the gain of a good antenna. In this case low attenuation cables, as well as high quality plugs (N or BNC), are definitely the better choice. The value of the cable attenuation varies with the frequency and is usually given in dB standardized for a length of 100 m. The attenuation of the individually used cable length can be easily determined by dividing the dB value specified for the cable and the frequency by 100 and multiplying it by the individual cable length. The connection of the coaxial cable to the antenna must be strain-relieved and weather-protected, with a plug that matches the cable diameter and the standard associated with the connection socket.

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Is a rotor absolutely necessary for VHF operation?

Maybe a 4el-Yagi will be mounted in a fixed direction to the next FM-relay. Longer Yagis and other directional antennas need a rotor to use their directivity effectively. Depending on antenna size, wind load, and weight, the market has suitable examples, ranging from small rotors for TV antenna-sized yagis to heavy equipment for rotating large array antennas. Elevation/azimuth systems are required for operation over earth-orbiting satellites and for EME. They consist of a combination of two rotors and can point an antenna both horizontally 360° in azimuth and vertically 90° in elevation.

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What do I need for VHF reception?

Reception only, what do I need? It depends: If you only want to listen to the closest FM repeater, a window quad mounted in the house, a short mobile antenna on the windowsill or a HB9CV in the attic is usually already sufficient.

For reception of distant FM or SSB stations up to DX in good conditions, at least a good omnidirectional antenna on the roof of the house or free-standing on a tubular mast is recommended. Some antennas have horizontal polarization and an omnidirectional patternm, for example the Big Wheel or the Halo antenna.

If you want to receive all bands in the VHF and UHF range, you should choose a Discone antenna. With its wide bandwidth and vertical polarization, it is the ideal antenna for omnidirectional reception.

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