# 6m/4m Yagi #

Dual band 6m-4m Yagi based on 6jxx6 from Sandro I0JXX.

This antenna was optimized with the goal to minimize any changes in 6jxx6 impedance/lobes.

The result is a 7 el on 70 MHz with a little loss of gain comparing with the other monobands of the same lenght.

If you don’t have so much space on your mast, like me, a dual band antenna can be a nice solution.

I chose to separate the sources of the 2 antennas because I’ve two rigs attached.

The 4m antenna has an impedance of about 27 Ohm, so we must use a matching circuit. The easiest way is to

use a quarterwave line of about 35ohm, achieved with a parallel of 2*75ohm cable.

I simulated the antenna with nec2 engine and the results are very close to the real values.

Thanks to Sandro I0JXX for hardware and Pino IK0SMG for help in matchbox assembling.

Measures:

2 Responses to “# 6m/4m Yagi #”

  1. Graziano Says:

    Puoi mandarmi il progetto dettagliato della dual band 50-70 mhz?

    • Provo a dettagliare:
      1) comprare/rimediare una 6jxx6
      2) comprare/rimediare 7 elementi diametro 12mm e i relativi isolatori
      3) tagliare gli elementi a misura ed inserirli lungo il boom della 6jxx6, le misure sono nella foto sopra.
      4) realizzare il trasformatore d’impedenza con un parallelo di cavi a 75 Ohm lunghi un quarto d’onda e collegarli al dipolo
      Non mi viene in mente altro, ciao.

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