Basic for antenna calculations

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The BASIC Formula / La FORMULE de base
                       143                              143
     Half-Wave = --------------    (F)   Demi-Onde = ---------
                    Frequency                        Frequence 

     (Wave is in meter [m], and frequency is in Mega-hertz [Mhz])     

     This "half-wave" basic antenna is the reference in order to
     comparare all other antenna practical realisations. We use for
     that "dB as power" with names "dBd" for horizontal realisations
     and "dBi" ("i" = isotropic) for vertical antenna realisations.
     ./.
     Cette antenne demi-onde de base est la reference pour comparer
     les antennes entre-elles. On utilise pour cela les "dB power",
     avec comme noms "dBd" pour les horizontales et "dBi" pour les
     antennes verticales ("i" = isotropique = toutes les directions). 

     If there is an impedance antenna matching with the transceiver
     you can use directly the S-meter to read dB value (as tension).
     ./.
     S'il y a une bonne addaptation d'impedance entre l'antenne et le
     transceiver la valeur dB est directe sur le S-metre (dB tension). 

(more DECIBEL (dB) informations)

Practical realisations / Realisations pratiques

1) Standard Vertical antennas (antennes verticales standards)

2) Best vertical antennas (meilleures antennes verticales)


(For "J" antenna the space between 1/4 wave elements is around 8 cm)

3) Accorded horizontal antennas (antennes horizontales accordees)


(The space between 1/4 wave vertical parts is around 8 to 15 cm)

4) The beaming YAGI system (le systeme directif YAGI)

5) The QUAD system (le systeme QUAD)

6) Relative antenna GAIN (Gain relatif des antennes)

The GAIN depends principally of surfaces in contact with environment,
and of course (also) with the lobes number and the directivity.
./.
Le GAIN depend principallement de la surface en contact avec l'invi-
ronnement, et bien sur du nombre d'elements et de la directivite.

Global systems comparison (dBd results comparison)

      1 - 1/4 wave type Marconi
      2 - 1/4 wave type Ground-plane
      3 - Standard vertical dipole 1/2 wave       (dBi reference)
      4 - Folden 1/2 wave vertical dipole
      5 - "J" 1/2 wave vertical
      6 - 5/8 wave vertical type Marconi
      7 - 5/8 wave vertical type Ground-plane

      8 - Standard horizontal dipole 1/2 wave     (dBd reference)
      9 - Folden 1/2 wave horizontal dipole
     10 - Basic 1/2 wave type End-Feed (Zepp)
     11 - Full-Wave type End-Feed (Double Zepp)
     12 - Levy system 2 x 1/2 wave in phase
     13 - Levy systen 3 x 1/2 wave (2 in phase)
     14 - Yagi directif system (more elements = more gain)
     15 - Quad directif system (more elements = more gain)

7) Directivity diagrams (diagrammes de directivite)

8) Matching antennas (accord des antennes)

The "Jones" circuit (also called "pi" circuit) is the standard
commercial "MATCHER", there is only one inductance and two variable
capacitors. The "Balun" is a special impedance transformer for high
frequencies, it is principally used for accorded horizontal antennas.
The "Gamma Match" is used principally for yagi and quad antennas.
./.
Le circuit "Jones" (aussi appele "pi") est le "MATCHEUR" standard
vendu dans le commerce. Il n'y a qu'une self et deux condensateurs
vaviables. Le "Balun" est un transformateur d'impedance special pour
les hautes frequences, on l'utilise pour les antennes horizontales
accordees. Le "Gamma Match" est plus specifique aux yagi et aux quad.

9) The Wave PROPAGATION (la Propagation des ondes)

The SUN FLUX ionize high atmospherique layers during DAYLIGTH hours. 
Wave are reflected by these ioninazed layers and the Earth. Highest
ionized layers give long "Skip". Ionised intensity give more bounces.

For example (picture) A to B is 6 skip bounces when A to C is 2 skip
bounces only. C can copy easily A and B but difficult between A and B.
./.
Le FLUX SOLAIRE ionise les plus hautes couches de notre atmosphere
durant la journee. Les ondes radio sont reflechies par ces couches,
ainsi que par la terre. Plus ces couches ionisees sont hautes et plus
le "Skip" est long, et plus d'ionisation cela donne plus de rebonds.

Comme exemple, A vers B est 6 rebonds alors que A vers C n'est que 2
rebonds. C peut copier facilement A et B, mais difficile entre A et B.


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