| DL9ECA |
Rating:  |
2024-10-22 | |
| perfect antenna for midsize space |
Time Owned: 6 to 12 months. |
| Bought the antenna end of 2023. Get great support from the owner Tom. He described detailed how the antenna works. Building the antenna was realy easy. All srews, nuts and holes where perfect drilled and everything matches togehter. It´s a very solid antenna with great performance. It´s mounted on a 24m (72foot) tower. It generates 2-3 S units better signal then my vertical on 40m. I would buy this antenna again. |
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| WB1CQW |
Rating: |
2024-08-30 | |
| Great performer. Challenging assembly. |
Time Owned: 0 to 3 months. |
| This antenna puts out a powerful signal, particularly on 40 meters. If I put out a call, I can expect one station after another to to break in and comment on my strong signal. It is quite large, with the longest element almost 50 feet. Its construction is robust and weighs in at 175 pounds hanging on the mast. Made in Germany, it cost me $4600 delivered. However, although the German-speaking manufacturer, Thomas S, has written a manual that in many spots I found very difficult to understand. He instructs the customer to hang the entire antenna BELOW the boom. Physically that would be close to impossible, requiring me to hold up heavy elements from below while attempting to fasten them in place. I therefore had no choice but to fasten the elements on TOP of the boom. Another problem was the pair of 3-foot phase lines which attach to the four drivers in series, but the manual doesn't explain properly where to find the attachment screws. Nor does not explain that the balun, provided by DX Engineering, should be attached at the driver element closest to the mast, the 20m element. Nor does it clearly explain that the two brackets and the little piece of plastic tucked in the balun box, shipped separately from the antenna itself--so easy to ignore and discard--all needs to be retained because the brackets make the actual electrical contact and the plastic acts as a spacer to hold up the balun on top of the boom. More seriously, the so-called decoupling stubs, consisting of 4 sets of plastic insulators and thin gauge wire, was lacking some of the proper size insulators, causing me to buy and jury rig (non-stainless) machine crews, not provided. Then too the attachment of the so-called parallelogram-shaped termination stub was a mystery until DX Engineering sent me a photo. Another area that was a mystery was how far to extend some of the 40m elements in order to get best SWR for phone SSB, which in the end I probably never got quite right. An overall problem is the peculiar way of fastening the elements. Thomas S. will use multiple size holes for each piece of aluminum pipe, and explain cryptically why his idiosyncratic attachment choice is superior to anything else. There's no way to tell which machine screws and nuts to use, other than to reach in the parts bag and "wing it." By the time I got to the end of the assembly, I had to buy some hardware to make up for the missing pieces. Due to these multiple problems, I went back and forth with Thomas S. by email, until he finally offloaded my case to DX Engineering, whose tech department was much easier to deal with. As a result of my challenges, I ended up writing a detailed report on installation, accompanied by my own photos. DX Engineering has kept this report on file in their tech department and will make it available to other customers with challenges assembling this excellent antenna. It has no traps, and I fully expect it will be the last antenna I will ever need. |
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| K4TOR |
Rating: |
2023-05-21 | |
| Excellent german made yagi |
Time Owned: 6 to 12 months. |
This antenna is built like a tank. The few questions I had during the build phase was promptly answered by Tom, DF2BO. Installed on a 75 ft tower. Performs as good or better than I expected.
Install instructions were straightforward, no screws, bolts or other items missing, every part fit perfectly, made of high quality materials, packed and labeled accurately.
SWR across all bands better than expected and specified.
Due to the build quality and sturdiness of this antenna, it is relatively heavy at about 140 lbs, so calculate accordingly when you get ready to install it. |
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| CE3DNP |
Rating: |
2017-08-25 | |
| My MM |
Time Owned: 0 to 3 months. |
It already has about 2 months installed to about 18 meters of height. The T2X moves it quite easily.
I have to say that after having had several antennas (6 EL-TET HB446DX, CUSCRAFT A3 and A4, M2 KT34 KT36, Hygain 204BA, etc.), OB12-4 seems to be superior to all those excellent antennas.
Absolutely nothing to say about mechanical construction, just out of range, will have to be a hurricane to damage it.
Neither can be criticized the electrical part of the antenna, being each element fullsize (10-15-20), have been allowed to occupy very precise distance between elements being of different diameter the tubes for each band.
With respect to the performance in the battle I had to flee from some pile-up that have become too intense (in 20 m CW). I can talk to stations between 1000 and 2000 (40m) here in Chile that I rarely could before. In addition now it is very easy to contact Europe, USA, etc. with both elements in 40.
I have been doing a lot of FT8 lately and with low power, 5 to 25 watts, I have achieved contacts in 10, 15, 20 and 40 meters practically without problems
I am very happy with my new antenna, with the great attention given by Tom, DF2BO. I consider that this antenna, for my taste, is the maximum so I have baptized it as Marylin (remembering M.M.)
Five stars with great pleasure. |
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| AF5IW |
Rating: |
2013-10-26 | |
| GREAT SUPPORT |
Time Owned: 0 to 3 months. |
| I bought a 6 year old OB 12-4 from MS moved it to TX and a new tower site, I was amazed at the quality of construction and condition. I need a few parts and contacted Tom at Optibeam and he sent me the small parts I needed so I could get the antenna on the air. The F/B and gain is amazing. first QSO bare back 100 watts Tokyo on 20M, Really great antenna from a great company! Thanks Tom!! |
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| W5DGM |
Rating: |
2011-11-30 | |
| What a Hammer !!! |
Time Owned: 0 to 3 months. |
| If I could give this antenna 10 stars I would. Boxes arrived a day ahead of schedule, and despite one box having a gash in the side, contents were safe and intact, thanks to excellent packaging. Assembly was straight foward, though the manual could use just a little clarification on some of the explanations. Once it was in the air (thanks WF5K,W5ABC,N5XES, & others who helped) it is a beautiful work of art. But performance - WOW ! I am able to work pretty much anyone I can hear, with only 100 watts. Strong, clean signal patterns, excellent F/B and low noise on receive are just some of the features I am experiencing with the OB12-4. This is truly an outstanding antenna. Thanks Tom and every one at Optibeam for a superior product, and most importantly outstanding service. Very highly recommended. |
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| IZ5MOQ |
Rating: |
2009-03-10 | |
| DX Beast! |
Time Owned: 0 to 3 months. |
After the OB11-3 ( http://www.eham.net/reviews/detail/2015 ) and
the OB4-2W ( http://www.eham.net/reviews/detail/2676 ) my new OB12-4 is, finally, installed!
Great antenna, very solid boom, mechanically indestructible!
Always installed between the mountains... but working very well. |
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| A71BX |
Rating: |
2008-11-18 | |
| amazing |
Time Owned: 0 to 3 months. |
I started to install the antenna before the CQWW SSB 2008, the installation of the antenna is simple and easy but you will need to follow the instruction of the installation carefully also I would like to add that all the parts of the antenna are marked even the boom!!
The antenna is heavy so don’t forget to choose a heavy duty mast to hold the antenna
The signals from the antenna are crazy and very strong this antenna is marvels specially on 40m band, signals on this band are 20db most of the time
The true exam of the antenna was during the CQWW 2008 SSB when we setup the station and start CQing on 40m band (WOW) we can hear any station calling on the band and they can hear us very easy too!
the most important thing is that we were able to increase our score in 40m band from 712 QSOs with OB1-40 on 2007 and 1400 QSOs this year with this antenna so we doubled the number of QSOs this year in this contest by this antenna also I would like to mentioned that last year we were using 4 elements SteppIR and OB9-5 for 20, 15 and 10m and the total number of the QSOs last year was 2647 with these antennas but this year the OB12-4 was mostly the running antenna in the station beside the OB9-5 and the total number of QSOs increased to 4000 QSOs and this is a big issue
SWR on 10m is 1.6 to 2, 15m is 1.5 to 1.2
20m is almost 1.2 to 1.1
for 40m 2.0 on 7000 MHz, 1.2 on 7050 MHz and 1.8 on 7100 MHz
Sometimes I will have QSOs on 40m with other stations, they usually get my call from first or second call and my signal is always 599 but later on I will find that I'm running QRP without a notice (hi)
Enjoy this great antenna
Thanks Tom (DF2BO)
de A71BX from A73A contest team |
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| SV2DCD |
Rating: |
2008-02-04 | |
| Great antenna |
Time Owned: 3 to 6 months. |
I own an OB12-4 for about 4 months now.Starting from the assebly i have to say that it was very easy and simple.It took me a couple of hours to prepare the antenna on the ground before i put it on the tower.Excellent work on the 40m coils.Nice support also for the 2 elements on this band.
As for the performance now, my OB12-4 installed at 26m high. The first thing i've done, was to check the swr on 40m band.Great results both ssb and cw segment.In my opinion i believe this is the most important thing for this antenna.Great swr on 40m band both cw,ssb segments!
After 40m band i measured the swr on the other bands.Excellent!Flat SWR everywhere.
On this 4 months period i've made plenty of dx qso's and had some participations in contests with great results.
I am amazed from the performance on 40m band.The antenna listens excellent.Never had an antenna with such low noise level on this band.Also with OB12-4 the phrase "first call" is now true for me.On the higher bands the antenna works also perfect.
I am very satisfied of my OB12-4 and i am suggesting it to anyone that wants great performance from an antenna with excellent F/B and F/R,no traps,great gain and quality product.It is a very good choice for antenna because it offers quality in low cost.
73 Leo SV2DCD |
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| N3KS |
Rating: |
2007-10-03 | |
| OptiBeam Update |
Time Owned: 0 to 3 months. |
I notice that in my review that it is not clear that I was comparing the Optibeam OB12-4 side by side with a friend's 2 element 40 meter beam. I just wanted that to be noted.
73 N3KS
----------------------
Earlier 5-star review posted by N3KS on 2007-10-03
I've placed the OB12-4 at the top of a 90 ft tower here in northern Maryland. Shipment of the antenna was smooth - Array Solutions (the USA distributor) and OptiBeam do a nice job of 'pre-clearing' everything, so it was waiting for me to pick up at the airport (Delta Cargo in my case.)
Some comments on assembly: 1) the parts are nicely marked, packed well and easy to identify, 2) the 40m elements are partially assembled when shipped - which is very helpfull, 3) everything is pre-marked on the boom and elements - there is no guesswork as to what goes exactly where. Nice job - the antenna can be built in less than a day by one person.
I chose the 40M CW segment tune setting for the antenna (all other bands are essentially flat SWR), and was pleased with how perfectly the SWR matched the expected results. This antenna is certainly designed with precision.
The performance of this antenna seems to be superlative. I do not have anything equivalent to test it against side by side - however, I ran side by side tests with a local ham who has a different two element beam at 53 ft height (note there is a height disparity), but who typically can hear very well. Band conditions were poor, but I worked a pileup on 40cw in the evening while my friend listened from his station, and I worked about 20 stations from Europe. Fully one third of the stations I succesfully worked - he could not hear well enough to get the callsign. Another third I worked easily, and were tough copy for him. This was not a scientific test, (and not 'apples to apples') but certainly gives an indication that the OB12-4 does very very well. In further 'playing' with it on the bands, I get the feeling that it is getting out and hearing extremely well.
I had a couple of questions for Tom, DF2BO, the owner of OptiBeam - and every question was answered quickly and thoroughly. Dealing with OptiBeam was/is a good experience for me.
In my view, the OB12-4 is a quality product with outstanding performance.
73 Kam N3KS |
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