ARI Sanremo Home Page Home Page Nominativo di Sezione ARI Sanremo
Home Main Menu Sezione ARI-RE Award Liguria EME Diploma Sanremo Search Members Downloads Forums Guestbook Login

Toggle Content Trova nel sito

Toggle Content .:Translate Language
Please select to change language

Klicken Sie auf Sprache ändern

Sélectionner pour changer la langue

Haga clic para cambiar el idioma
Autori › The rotary dipole
The rotary dipole

We possess only what we really understand

The rotary dipole

      This antenna is derived from an idea of Bud W3FF Link esterno. Built by me, tested and adapted with the available materials, to our needs of easy repeated assemble and disassemble, low weight for portable operations, and last but not least, the cost.

As you can see from the drawing, it's small, strong and robust, easy to assemble and to use; once the positions of resonance on the various bands are found, repeatability is like a game.

To build it, you will need a lathe, or find a friend with one, an do a little screwcut. You will also have to look around to find a surplus whip of given dimensions. The remainings are common materials. It will not require too much time, but do not underestimate the job.

In order to find the resonant positions in the various bands, proceed as follows: in the field, far from obstacles with an RTX and ROS meter install the antenna not ess than 2 ½ mt high. Climb on a stair and start with the 40 mt band. With all the coil in, move the tips of the whips and find the maximum watt reading (not the SWR). Always stay far from the antenna when you measure.

Once found max output lightly mark the "hot" side, then slightly adjust the opposite leg to find the lowest swr value (always keep away from antenna when you measure); mark this position.

For 14/21 MHz bands you will need to find the short circuit position on the coils. They are indicated, but it will be necessary to verify them due to the many factors that influence the performance.

Open fully the whips less two cm. and begin to equally short-circuit turns on the coils from outside to inside. Once resonance is found fine adjust the whips for best SWR.

On 28 MHz, if your whips are the same as mine, take away the coils and fixed parts and set whips as per formula: length in mt = 142.500 : f (KHz) / 2

Example: if we need 28060 KHz, then 142500:28060 /2 = 2.53 mt each leg.

This is an indication, now work it out yourself for your pleasure.

This antenna works well, I tested it on the Ligurian Alps working SOTA and making an incredible quantity of DX ing with 1 watt!

If you want, on your car with a small d.c. antenna rotor and internal control box, it will turn in 40 seconds. It's useful only in contest or in the cold season; otherwise you can turn it with your hands...

Please find here below the drawing: The rotary dipole 

Attilio, I1BAY

(3368 reads) Printer Friendly Page

[ Return to I1BAY ]

Nominativo di Sezione
Sezione A.R.I. Sanremo - 18.02 codice ASC che per la Sezione è G08

La Sede si trova in corso Mazzini n° 1, a fianco del Campo Sportivo, in Sanremo. La Sezione è aperta tutti i martedì, non festivi, dalle ore 21 alle ore 23 circa.

Indirizzo Postale:


Scrivi al Segretario
Indirizzo di posta elettronica certificata

Webmaster IZ1OQB PINO

Contatto per il Webmaster
Regolamento del Sito | Note Legali/Disclaimer | Come trovarci

Best viewed 1024x768 +

Questo sito appartiene alla Sezione ARI di Sanremo (IM) e non rappresenta una testata giornalistica in quanto viene aggiornato senza alcuna periodicità.
Non può pertanto considerarsi prodotto editoriale ai sensi della legge n. 62 del 07.03.2001.
I loghi, i marchi e gli script usati in questo sito appartengono ai rispettivi proprietari e a CPG-Nuke Team.
Questo sito utilizza la versione 9.2.1 di Dragonfly CPG-Nuke.
Theme by i1yst
Tutti i testi, le foto e i disegni tecnici sono esclusiva proprietà di © 2002-2013
Vietata la riproduzione e la copia, anche parziale, senza la previa autorizzazione di

All content are protected by the copyright law and may not be copied without the express permission and the active reference to a source!
Web stats

Interactive software released under GNU GPL, Code Credits, Privacy Policy

placeholder Support   Dragonfly   XHTML valid!   CSS valid!   Level Double-A Conformance icon, W3C-WAI Web Content Accessibility Guidelines 1.0   RSS valid!   Robots valid!   PHP   PhpMyAdmin   MySql   Get Adobe Reader   Unicode   Add to Google placeholder