IZ1DFF  ITALIAN HAM RADIO STATION                                       > English


EnglishItaliano

Fishing pole antenna Rybakov

or rather how to fish DX

Nowadays it seems that an OM is not a real OM if he doesn't build an homemade fishing pole antenna called Rybakov. For this reason I begun to build this antenna starting from the BALUN 4:1 (or better UN-UN 4:1*) that is the heart of the antenna and the the most challenging element.
We know that the radiant cable we will use will be 3/4 wave of the higher working frequency and in that case we will find a 200 OHM of impedence and for this reason we will need a BALUN 4:1 to adapt that value to 50 OHM (200/4) of our radio.
I used the toroid AMIDON T200/2, on it 19 turns of a couple of  0.5mm enamelled copper. If you don't have enamelled copper you can use an ordinary red-black cable.
Here you can find the cables interconnections:

Antenna canna da pesca,schema BALUN 4:1

Remember that one turn is when the cable crosses the inside part of the toroid.
The union of the two different cables, after the 19 turns, will solder to the central of PL while the ground cable will solder to the cable shield and to an external ground cable that is better if will be 1/2 wave of higher frequency long.
The third cable will be connected to the radiant cable of the fishing pole.

With this solution we will a "full range" antenna usable from 3,5 to 30 MHz with good ROS values.

Here you can see my BALUN 4:1 inside an industrial IP66 box water resistent.

   Antenna canna da pesca, BALUN 4:1
click for full size

Antenna canna da pesca,BALUN 4:1 interno
click for full size

When you have finished your BALUN 4:1, the fishing rod antenna is almost finished. All that you have to do is to 
hoist the fishing rod, fix the cable on the tip and on the BALUN also not in a straight line but "screwing up" if necessary.
The theoretical results already meet expectations. In fact, simulating the antenna load of 200 Ω with two resistors of  100 Ω in series, can be seen as the BALUN 4:1 adapts the impedance to the 50 Ω on all amateur bands from 10 to 80 meters:

MFJ e BALUN 4:1
click for full size

3MHz 7MHz 10MHz 14MHz
18MHz 21MHz 24MHz 28MHz


ROS

* The transformer impedance acts on the reactive part of impedence reducing to the resistance value.
We define balanced  elements the symmetric antennas (eg dipole) while it considers unbalanced (not symmetrical) the antenna cable or single-line items.
We use the BALUN when we want to adapt a symmetric antenna (BALanced) to the antenna cable (UNbalanced)
We use an UN-UN to adapt a not-symmetric antenna like a fishing pole antenna (UNbalanced) to the antenna cable (UNbalanced)




> English