Cubical Quad

Since I had the Hexbeam, I never did any comparison with another antenna. After some simulations on 4nec2, the project was ready : 2 elements on 10m.

I chose a monoband on 10m because this project was not studied for an definitive installation, only two weeks of life...

During the design on 4nec2, I found two impedance profiles : Around 50 ohms and another at 100 ohms. I prefered the 100 ohms version, it had a wider bandwidth and a better front/back ratio but the gain is a little bit lower (less than 1db).

A quater wave of 75 ohms coaxial transforms the impedance at the feedpoint, and I think it brings also a more linear SWR. I found this feeding system very efficient.

I will not detail the mechanical part of this antenna because it was not the project subject. The wire was bare copper of 2.5 mm2 (about 14 awg) and antenna was at 7 meters above the ground.

- Radiator : 10.68 m

- Reflector : 11.32 m

- Boom : 1.35 m

-Frequency : 28.200 mhz

I was very happy to test a Cubical Quad, of course it’s a monoband and compare to the Hexbeam is not very fairplay. I think my future antenna will be a 3 elements Quad with 5 bands. But I also see the importance of mechanical part, it's the key to obtain a durable antenna especially with hard WX conditions.

What wonderful antenna !

The project purpose was the comparison between this two antennas in order to help me to choose my future antenna system. The cubical quad wins at all steps:

- The RX difference is not huge but can be clearly heard, about 1 to maximum 2 s-meter points. But sometimes there was absolutly no difference.

- In TX there is a larger gap and 80% of OMs have heard this. 1 or 2 s-meter points and a stronger radio.

During my tests, I was running some stations when Alex (PY1HAD) called me. It was the first time I made a QSO with him and he wanted to test his new configuration (KX3 + Alexloop), he was also filming the QSO. After have finished his tests we proceed to the comparison of the Hexbeam and Cubical Quad. When I saw the video on Youtube, I was surprised to clearly hear a big difference between the two antennas.