Horizontal HF 6-Band turning arranging emitter with 2 elements "Maria Maluca"
Since 2004 I have a small garden in Berlin. After the house was built and worked some small contests with the existing portably wire antennas, 2007 the desire for swivelling multiband HF antenna arose.
Due the relationship its an allotment plant, a property size and a general antenna prohibition with fixed installation, I thought of a small horizontal 2-Element Yagi, which can be diminished with a sliding mast fast up and down. I had good experiences from our club station in the OV-D08 with the "Fritzel FB-2". However, the "FB-2" is only a 3-Band antenna with traps, quite heavy, and the purchase price is quite high.
In the InterNet I found concrete referring to "Maria Maluca" with the search word "2-Element" then to the side of DB9EX from DC6NY with operational principle, beautiful pictures and an assembly instruction with measure data. DC6NY described and offers its antenna in the "Funkamateur" a material set for an computer-optimized 6-Band 2-Element "Maria Maluca" directional antenna.
About "2-Element" I found some in the "Rothammel (red mutton)" Antenna Book. However the term "Maria Maluca" (crazy girl) is missing in the 12. edition. In the 9. edition and before, Maria is to be found.
I decided for the self's building. From earlier times I had still another 3-Element Yagi for 27/28 MHz which I converted. This CB antenna "Lemm D-3", is an ultralight aluminum pipe antenna. The boom pipe consists 2 parts with ever 1300 mm (2600 mm boom), a dipole exciter with approx.. 5600 mm, reflector with approx.. 5800 mm and director with approx.. 5500 mm of length.
I extended the dipole exciter and the reflector with 8 mm aluminum pipe by the necessary lengths to 7560 mm and 6640 mm. As boom pipe I use a part with 1300 mm. The second part of the boom pipe can find later still for modifications use.
The feed first, as usual, realized 450 ohms "Wireman" feederwire with 13400 mm are enough, on 4:1 Balun and Antennentuner a FC-901. At first attempt QSO with LU5 and JA9 arrives. With the rotor this line however constantly rotated and rested directly against the metal mast. The adjustment SWR constantly changed also by wind. After attempts with measuring rods to the mast I broke gene FFS off. "Wireman" feederline is not suitable for spinners at the metal mast!
The improvement lies to replace the open two-wire line "Wireman" by a shielded two-wire line.
For years I use in home QTH an inlet from 2 times RG-62, led in the pit. Thus I made very good experiences.
The RG-62 has ca.100 ohm and is similarly "Aircell". With cable straps 2 cable ends, parallel and directly long, are bound together. That results in a cable impedance of approx. 200 Ohms with the RG-62. The screen is interconnected at both ends and grounded at the antenna adjustment equipment. Antenna-laterally only the two interior leaders are attached at the dipole.
Device-sided the interior leaders are attached at the 4:1 Balun. The cable can be fastened now firmly to the mast pipe. Now the VSWR is always constant after tuning with the Antennatuner. The overall length of the shielded two-wire line, with me ca.14000 mm, depends on the requirements is not critical.
General sample was the IARU Contest 2007. There could create 650 QSO in 18 hours. On "Maria Maluca" came 314 QSO (139/20m, 178/15m and 97/10m). When aggressive calling it could have been also more. On 20 and 15m could be worked easy all continents. On 15m it has the strongest directive effect. 20m it affects nearly bi-directional. In the DX- Pileup was not completely so strong, however nearly always went to the third or fourth call. Also many strong signals on 10m, here due the propagation conditions only little DX. In the comparison to the 1/4 vertical and the tuned 2 x 10m dipole ever stronger DX signals. On 40, 80 and 160m I used a vertical antenna HF2V even built, but that is another story.
The large advantage "Maria Maluca" is that the antenna is tuning by the Antennatuner also on 17, 12 and 6m es well. Even on 30m she goes co-ordinating. It possesses no Traps and stands depending upon Balun and Antennatuner much quite achievement. It is much easy and can also at small masts, e.g. with the Fieldday or on journeys be operated. A so small DX antenna, which plays on 6 HF Bands, nevertheless so surprisingly well. But unfortunately "Maria Maluca" has due to her operational principle the disadvantage that on 12, 10 and 6m the radiation direction turns around. The director becomes the reflector.
In the case of extension of the boom pipe on double length 2600 mm, the elements approx. 7900 mm ,the feed is possible like W8JK. The antenna direction is then bi-directional on all Bands. One needs 180° at the rotor only. Thus the open two-wire line does not wind itself around the mast with the rotation of the antenna. However the profit drops somewhat.
A profit increase 10 dB on all Bands and W8JK feeding, offers 2600 mm the element extension with boom length like Moxon.
Christian DL7JV, July. 2007
Links about "Maria Maluca":