Hello from Austria!
What should I say? First, look to my review of the OB11-3, please!
Meanwhile I added up a partly home-made rotary dipole für 40, 17 and 12 m, mounted about 1,5 m above and parallel to the OB11-3 boom. It worked quite well, specially in DX if you show the "nice face" toward to the station. Of course, I noticed a big difference against the 3 element beam on the other bands.
Well, first I checked the location on the mast on my roof and then my financial situation, of course. Ok - OB13-6 should be possible! A few emails with Tom and the deal was perfect.
A big truck of a well-known shipping agency stopped in front of my house - and the first thought was: "Tom made a mistake - he sent me two antennas...". Two large and one smaller well-packed boxes, 95 kg in total were indicated on the bill.
And now, my "one-man show" could start: opening the boxes; every item included and carefully marked, packed perfectly and secured against transportation problems, especially the 40 m coils. Many parts are preassembled. It took quite a long time to carry up all the parts to the attic because of my only 25 degree sloped roof, I decided to assemble the beam outside on the roof, right below the mast.
Starting on the next day, fitting the 80 x 80 mm boom together - "Oh my God, did I really buy the right antenna?" - a few hours later I got used to its dimensions and everything went well. By the way, I guess that there are two sizes of wrences and two different hex tip wrences necessary only – and these hex tip screwdrivers were included! As it is my second Optibeam, the manual at the beginning was not so important for me, everything marked clearly, so the beam grew - every assembling step is described exactly in the manual and you don't need any assistance. Of course, if a second person would like to help you, don't say "no, thank you"...
Four days later, after about 30 hours of work - (You will be able to assemble the beam on a flat ground in half a time or less; it's not so easy to walk around on a 25 degree sloped roof, because you cannot leave any parts or tools on the roof, you'll find it either in the gutter or down on the ground...) - I was ready to lift it up to approximately 2 m above roof level and do the first SWR check. A little bit nervous I started taking measurements - imagine 6 bands on one antenne only - but even on that low altitude SWR on each band was perfectly. I wonder, "Is it really the beam or is it the dummy load?"
On 40 m I did a small correction because of the new 7,2 MHz limit for Europeans to get the resonance on 7,1 MHz. This was done very easily, there are, I guess, 6 predrilled holes and exact information in the manual to match the desired frequency.
After the final check, I continued to lift up the "eagle" to the mounting position, very slowly with my hand pulley block. The only minor problem is, that due to antenna-design, it is not possible to install the boom-to-mast-plate exactly in the mass centre of the boom. So I fixed up temporarily an additional rope to the rear of the boom and with the help of a small single pulley on top of the mast I tried to keep the boom in a good horizontal position during the "lift off".
After fixing the OB13-6 with the first of the 4 U-bolts (all hardware stainless, of course!) on the rotary tube, I took a deep breath...
While I pulled up the antenna, I did not check the last rung of my mast and the 12 m driven element got caught on it and was severely deformed. In an email I told Tom my problem and a few days later I got a new driven element - free of charge. That's customer service! Many thanks!
What do I say about performance? I works perfectly - I noticed no difference on 20, 15 and 10 against the OB11-3, 12 and 17 also working excellently - the rotary dipole no match for the OB13-6.
40 m: performance within Europe - first I was almost disappointed because of little difference on the f/b-ratio with S9+20 and up signals, but on low-level signals and in DX traffic, turn the antenna into the opposite direction or change to the wire dipole, no more comment neccessary - 2 elements are doing exactly that job.
My SWR about 6 meters above roof, 2-level house, overall about 16 m above ground:
24: 1,3 - 1,4 (min./max)
21: 1,0 - 1,5 (min./max)
17: 1,25 - 1,4 (min./max)
14: 1,0 - 1,12 (min./max)
7,0: 2,2 7,08: 1,0 7,2: 2,2 (high Europe-phone)
28,0: 1,3 28,8: 1,2 29,2: 2,0
Summary: perfect designed beam, 6 bands, 1 feedline only and excellent performance. Mechanically properties are perfect too; the square boom makes the alignment of the elements very easily and a clever guy-system (2 x 40 m elements and 1 x 20 m incl. 12 and 17 m sleeve elements) gives minor hanging of the elements, so the optical appearance is fine and looks better than the OB11-3. This larger beam is even more stable under stormy and snowy conditions than the previous one. The centre boom anchoring is pre-assembled too, but when fixing the outer ends of the stainless steel rope make an exact cross-check of their position to match the length with anchor centre position on the rotary tube above the boom.
I did a lot of fotos during assembling, if you are interested, drop me a line! Cu on the bands!
73, Gerhard – OE6TGD, JN77kf |
