Funkanwendungen. LR4. Gedanken zum Thema Antennenanpassung. 1.
Vorbemerkungen Als Amateurfunker läßt es sich eigentlich nicht vermeiden, daß man mit genau diesem Thema immer wieder in Berührung kommt. Konkreter Anlaß, daß ich mich mit dieser Thematik befasse, ist, daß ich mir einen Antennentuner (Antennenanpaßgerät) gekauft habe, um vor allem beim portablen Amaterufunkbetrieb eine einfache Vertikalantenne für Kurzwelle an die Impdanz meines Transceivers anzupassen. Daß eine Anpassung notwendig ist, zeigt folgendes einfache Beispiel: Ein 10 meter langer Draht, der entlang eines Glasfibermates einen Vertikalstrahler darstellt, hat auf der Frequenz 3,7 MHz (80 m-Band) eine Impdanz von etwa (6,6-j502) Ohm.
Bei 7,1 MHz (40 m Band) liegt die Impedanz bei (33,3-j210) Ohm (Die gesamte Thematik Erdnetz, Radials, Bodenleitfähigkeit etc. lasse ich außen vor, weil sie für das Thema Anpassung nicht relevant ist).
What tuners do. Follow the discussions on any Internet Ham Radio forum and it wont be long before someone comments that: "A tuner in the shack can't affect the match at a remote antenna feedpoint", or: "A tuner simply 'fools' the radio into thinking it is matched".
On this page I'll show that both these statements are incorrect! Firstly we need to understand something about "conjugate matching". I guess most folk are familiar with the "Maximum Power Transfer" theorem which says that if a source has a source resistance of R we can extract the maximum power from it if we provide a load of resistance R. The Mystery of radials. The mystery of radials Introduction (I) Many publications have examined the mystery of what effect radials have on the efficiency of antennas.
Instead of describing each article, pro or con, what does the "Bible", I mean the various editions of The ARRL Antenna Book, tell us on this subject ? For short, according to exhaustive tests conducted by RCA in New Jersey in 1937, ARRL refers to FCC that specifies that to get a low-loss ground system using a 1/2l vertical, 120 radials equally spaced and each at least an half-wave long extending radially from the base of the antenna are needed on the lowest working frequency.
They must be grounded to prevent shock and other damage. Antenna_vertical_short_radials. Patent US4658266 - Vertical antenna with improved artificial ground system - Google Patente. The present invention relates to antenna systems, and more particularly to vertical antenna systems employing artificial ground means in the form of either a counterpoise or ground screen.
HB9MTN MULTIBAND H-POLE. After several attempts to build a multiband C-Pole I finally ended up with the Multiband H-Pole.
C-Poles for different frequencies on one pole must be fed with separate feedlines over separate current baluns. In a first attempt I fed the H-pole in the center with a ladder line. DK0TE - Duale Hochschule Baden-Württemberg Ravensburg Campus Friedrichshafen. Messung der Erdbodeneigenschaften. Motivation Bei der Simulation von (Vertikal-)Antennen sind als zwei entscheidende Faktoren die Leitfähigkeit und Dielektrizitätskonstante des Bodens bei Hochfrequenz einzugeben.
Genau diese Werte sind aber bisher nur Schätzungen oder einfachste Karten für Lang- und Mittelwellensender. Angaben für den Kurzwellenbereich sind überhaupt nicht zu finden. Dabei sind die Bodeneigenschaften sehr von der Frequenz abhängig. Daher möchte ich diese Werte über einen längeren Zeitraum zusammen mit der Niederschlagsmenge und Temperatur selbst beobachten. Ausbreitung von Langwellen und Mittelwellen.
Revisiting medium-wave ground-system requirements. The classic 1937 paper by Brown, Lewis, and Epstein  outlined the necessity for a proper ldquoimaging screenrdquo or ldquoground systemrdquo for efficient operation of a vertically polarized monopole antenna.
While Brown et al. showed the effects of various configurations, they did not exhaustively examine the effects of successive reductions of the number of radials, particularly in systems with radial lengths less than 90". Furthermore, their measurements were made at 3 MHz, and were not corrected for the frequency scaling. Patent US4658266 - Vertical antenna with improved artificial ground system - Google Patente. The present invention relates to antenna systems, and more particularly to vertical antenna systems employing artificial ground means in the form of either a counterpoise or ground screen.
The efficient operation of a vertical antenna for transmitting or receiving requires that the antenna be used in conjunction with a "ground". The type, size, physical construction and electrical characteristics of the choosen "ground" determine the performance, efficiency, ease of feed and radiation pattern of the antenna system. Basically there are two requirements for a good "ground". First, the ground must provide a low resistance path for the return of those currents resulting from the radiated field of the antenna. Using elevated radials with ground-mounted towers. Antennas radials.
Ground System Configurations for Vertikal Antennas - Startpage Web Suchen. Startpage offers you Web search results from Google in complete privacy!
B. Cebik, W4RNL he term counterpoise has a long history in antenna engineering and amateur practice. Today, it may be among the most misused terms in amateur circles. Indeed, if we examine both the history of the term, its meaning, and its misuses, we might reach an interesting conclusion: there is no such thing as a counterpoise in antenna analysis, even though the term has a long and somewhat respectable use in antenna engineering. Although my bookshelf has many gaps and covers antenna history in fits and spurts, we can detect some trends in the use of the terms, along with the seeds of misuse.
The Rise and Fall of the Counterpoise. H-pole_DK5VQ.pdf.
AM broadcast antennas with elevated radial ground systems. Fuji X10. AGANDO Shop - Allround PC-System AGANDO campo 2161i3 gt AGANDO campo 2161i3 gt 105832. Patent US4658266 - Vertical antenna with improved artificial ground system - Google Patente. The present invention relates to antenna systems, and more particularly to vertical antenna systems employing artificial ground means in the form of either a counterpoise or ground screen. The efficient operation of a vertical antenna for transmitting or receiving requires that the antenna be used in conjunction with a "ground".
The type, size, physical construction and electrical characteristics of the choosen "ground" determine the performance, efficiency, ease of feed and radiation pattern of the antenna system. Basically there are two requirements for a good "ground".
Free Electronics Engineering Books Download Free Electronics Engineering Ebooks Online Electronics Engineering tutorials. Free Modification and Manual-Page for HAMs. Free Communications Systems Books Download Free Communications Systems Ebooks Online. Nec calculation of impedance - Startpage Web Suchen. Digital Modes. Digital modes are becoming more and more popular on the amateur bands. This is mainly due to the following reason: Affordable home PC’s with built in soundcards.
This has brought forth a multitude of decoding software, some free, others not. There are new modes being invented all the time and keeping track of these is turning into a full time job! One of the main problems encountered by the newcomer to digital modes (or digimodes as they are known) is how to identify what they are seeing/hearing. Most of the decoding software uses a visual ‘waterfall’ display to facilitate easy tuning. With that in mind I went on the bands and captured images of the most common digital modes in use at the moment. An 'Odd' but Fun Digital Mode. JT65-HF -- an 'Odd' but Fun Digital Mode Dave Dunbar (N0RQ) on April 6, 2011 View comments about this article! In case you’ve never seen it before, let’s explore a seemingly-little-known digital mode called JT65-HF.
In some ways, it is very similar to other digital modes such as PSK31, but it some ways, it is very much different. First, the similarities. The equipment required is the same as other digital modes, that is, the rig, the antenna, the computer with software, and a sound card interface. IZ4CZL - JT65A current spots. ROS v7.0.5. Install & Operate JT65 in under 5 minutes. DARC OV M05. DK0IZ-AKTIV! OV M05 » Allgemein. GARMIN. Wir freuen uns sehr über Ihr Interesse an unseren Garmin Produkten. Gewährleistung - Reparaturservice. Anmeldung für die Unterstützung.