Taliansky výrobca antén ECO pod číslom produktu 279 ponúka tribander on 10m – 15m – 20m without the possibility of extension to other bands. Trapped tribander is produced by several companies, while probably the most famous tribander is Cushcraft A3S. How is ECO different?
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ECO tribander
ECO tribander is a two-element trap antenna with curved elements (like Moxon beam). The manufacturer chose an emitter-reflector combination, while designing the antenna to have an impedance of 50 ohms at the feed point. The dimensions are thus smaller than the classic one yagi, najdlhší prvok má rozpätie 550cm a boom 350cm. Váha je necelých 15kg.
Due to the limited space options on the roof, I was so interested in the ECO tribander that I bought one at the beginning of the year.
Features declared by the manufacturer
| Bands: | 28-21-14 MHz |
| Performance: | 2 kW P.E.P. |
| Impedance: | 50 Ohm |
| Profit: | 9 db |
| Front-to-side ratio: | 38 db |
| Front-back ratio: | 25 db |
| Boom length: | 3.50 m |
| Longest element: | 5.50 m |
| PSV: | 1:1,1 |
| Connector: | SO 239 |
| Antenna weight: | 15000 g |
| Boom stainless steel | |
| Resistance to wind speed: | 130 km/h |
| balun | in accessories |
| Elements - AL pipes | |
In the cardboard box you will find all the components of the antenna and a detailed procedure for assembling the antenna. The Italian antenna companies did not "disappoint" and so I added a few washers and nuts to their material. Otherwise, the box was filled with many pages of Italian newspapers, hi.
Opracovanie dielcov je presné a dobré. Assembling the antenna is easy, but I recommend first assembling the elements and traps. There is a hole on the underside of the traps through which the water is supposed to drain. If you mount the elements on a boom without traps, you may have to turn them over after installing the traps so that the hole is on the bottom side.
The ends of the elements face each other and there is an insulating line between them. Don't be surprised that the elements are slightly bent (like a bow) after their installation. The 1:1 balun is fixed above the boom. After connecting the coaxial cable, treat the joints against water ingress.
Anténa nemá žiadne nastavovacie prvky. The manufacturer reports very good PSV curves on all bands, which is quite brave, because otherwise the antenna will behave a few meters above the ground and, say, on a mast at a height of 40m. In a small range, it is possible to change the spacing of the elements and thus correct the antenna setting.
Úchyt na stožiar by mohol byť masívnejší. The console begins to deform when the nuts are tightened more strongly.
In my case, the antenna is about 14m above the ground on a sloping roof made of eternite. A few tens of centimeters from the antenna is a high lightning rod and about three meters away is the end of a 5-band dipole. Anténa má PSV v pásme 20m a 15m výborné, najnižšie je v SSB segmente. Aj v telegrafných segmentoch je veľmi dobré. V pásme 10m je PSV vyššie. Najnižšia hodnota je 1,3 a to na 28,2 MHz. Na 28,5 MHz je 1,7 a na 28,6 MHz 1,9. Zrejme sa na tomto pásme prejavuje blízkosť okolitých predmetov.
How does the antenna behave in sharp operation?
Anténu preveril najmä IARU HF Championship a príležitostná DX prevádzka. Desiatka je poväčšine zavretá, takže tri desiatky bežných DXCC z Európy, Ázie a Afriky nie je smerodajný výsledok. Pokusne som skúšal dovolávanie sa s QRP also 100W. On 5W it required more patience and some stations could not even be called. Conditions are conditions, no antenna can deceive them...
Pásmo 15m býva otvorené častejšie. Podarilo sa zalogovať napríklad 5U na prvé zavolanie, CN, CT3, LU, OH0, PY, T7, ZD8 a ďalšie. Tu som QRP neskúšal, používal som 100 až 300W.
„Dvadsiatka“ je asi najlepšie otvorená v týchto mesiacoch a tak sa venujem najmä tomuto pásmu. A je to poznať. V logu je množstvo staníc z Ázie (4S, 9K, 9M2, A4, A7, AP, BV, BY, HL, HS, JA, S2, VR2, VU, XU, YA,…), Afriky (5X, 6W, 7X, 9Q, ET, J2, S7, ZD7, …). Z Pacifiku zatiaľ len blízke 9M6. Asi najcennejšie je VP8/F, kde bol poriadny pile-up. The power used is mostly 300W.
Despite only two elements that suggest that the radiation pattern is wide, it pays to point the antenna precisely. Porovnávanie s 5-pásmovým dipólom Diamond W-8010 je jednoznačne v prospech smerovky. S-metrovo vyjadrený rozdiel je +5 až +30dB. dipól samozrejme stráca veľa, keďže ho nie je možné natáčať ako smerovku.
Rozhodnutie rádioamatéra prikloniť sa k tej či onej anténe je aj vecou pocitu. Medzi plusy antény môžete zarátať aj možnosť použiť malý Rotátor, AR-300XL, a odolnosť vo vetre. A week after installation, a windstorm swept through the Tatras, tearing down several roofs and uprooting a few trees. However, it did not harm the antenna at all, even though the wind was leaning against it quite a bit.
„Z núdze cnosť“ – kvôli priestorovým možnostiam som nemohol realizovať zamýšľaný spiderbeam, let alone a classic trapped tribander. However, the ECO 279 runs well. If you are looking for a compact antenna for three bands, consider whether it is not a suitable choice for you as well.