This year I had to honor to be invited by the Qatar Amateur Radio Society (QARS) to operate the CQ WW SSB contest with them. The station set up in a fieldday style on the northern tip of Qatar, about 100km way from the capital Doha. We are directly located at the beach and used almost exclusively vertical antennas. A73A entered in the category Multi Operator / Multi Transmittors, running 6 Stations in parallel. Keep on reading for some pictures and lessons learned.
The location was selected very carefully. The station was located in bay on the northern tip of Quatar surround by almost 260º of salt water. Due to the nature of this bay, the water was very shallow and even with stronger winds, there were no waves on the water. From the Gulf region, Europe and the US are the same heading direction which favors a simpler antenna setup.
Antenna setup on the Highbands (10m…40m)
On all highbands (10m…40m) we used a phased array of 2x 2el N6BT Bravo verticals. These parasitic two element vertical arrays consist of a driven element and another element which can be alternated with a coil & relay to act as a reflector / director. The big advantage of these antennas are their physical dimensions. They can be easily installed by one person. With their two resonant radials no additional radials have to be installed.
The driving element was fed through a W2DU current balun. Driving the antennas with 1,5kW heated up these baluns excessively. After 39 seconds keydown you couldn’t touch them any more. A few seconds later they went into saturation and significantly and worsened the SWR of the antenna.
I’m not sure if these high amount of common mode current is a design problem of the antenna (feeding the antenna not on Lambda/4) or selecting the wrong kind of ferrite material for the W2DU balun.
Anyhow, the antennas worked great. Supplemented with a W0XB Stackmatch II Plus (enabeling InPhase / Out of Phase) we were able to cover 3 direction with each double pair of verticals.
- Endfire (Reflector + Driver) towards EU / NA
- Endfire (Director + Driver) towards VK
- Broadside (The two vertical arrays out of phase) towards LU/PY and UA
Unfortunately, one of the stack matches was wired wrong and we transmitted the first day on 40m always broadside. The deep null in the antenna pattern towards EU/NA resulted in very little QSOs. Fortunately we found the problem the second day so that we could at least recover a bit.
The only Yagi we had was a A4S connected to the 10m station. Within the same beam direction, the verticals were always louder than the Yagi. However the Yagi became useful in working multipliers which were off the main beam directions of the vertical array.
Antenna setup on the Lowbands (80m & 160m)
On 80m we set up a classical 4 Square with two elevated radials for each vertical. The antennas were standard aluminium tubes sold be DX Engineering. The 20m tall verticals were phased with a Comtek Coupler enforcing the right current at the feedpoint with a Quaterwave 75 Ohm Transformation line.
160m had another 20m tall aluminium vertical with an L-extension making the antenna resonant on 160m. Two elevated radials were added.
All antennas performed amazingly good. Especially the front/back and front/side of the 80m 4-Square was very impressive.
Unfortunately, both – our beverage towards EU and the K9AY loop didn’t work. While having some kind of ground loop noises on the Beverage (unfortunately we couldn’t find the root of the problem in time) the K9AY worked equally in all directions. I’m personally somehow fed up with this antenna now. I´ve already tried severals in different parts of the world with kits of different manufactures and non of them worked properly.
The Shack & Infrastructure
The whole operation was splitted into four temporary housings of different sizes. Two were used as shacks, one for sleeping and one as bathroom and kitchen. All of them had were airconditioned which is in Qatar a necessity rather than luxury. Within the Shacks we used almost on all bands the same setup:
1x FT2000 or FT1000MP MK-V
1x Microham MK2
A73A consisted of a multi national mainly of the GCC states. Here is the list of operators:
- A71BX, Ali
- A71CV, Abdulla
- A71Co, Khalid
- A71AM, Saif
- A71AD, Rashid
- A71EL, Mohammad
- A41MX, Farid
- A61ZX, Ibrahim
- HZ1DG, Abdulrahman
- 9K2RR, Faisal
- 9K2HN, Hamad
- K5GN, Dave
- DH1TW, Toby
Station: A73A Class: M/M HP QTH: Qatar Operating Time (hrs): 48 Summary: Band QSOs Zones Countries ------------------------------- 160: 340 13 62 80: 1134 27 92 40: 1081 27 101 20: 2280 40 145 15: 2815 40 147 10: 3978 40 161 ------------------------------- Total: 11628 187 708 Total Score = 29,229,805
Pictures have been taken by A71BX, HZ1DG and A41MX