Beam Steering in Combat or How to Use Software Radio and an Array of Short Verticals in the 2008 ARRL International DX Competition Note that I used spotting assistance even though I operated only one band. Therefore, I have to submit as either Single-Op All Band Assisted, or Mutil-Op. So, for the 3830 reflector, I am using the SOSB/160 category, but I will submit my log to the ARRL as Multi-Op. I had intended to operate casually this year, but the station worked so well that I wound up going nearly all out. I passed last year's QSOs and multipliers the first night. The Electronic Beam Steering Phased Array and SDR Receiving System (still looking for a short name, maybe "Beam Steering Rig" this time) seems to finally have exceeded the performance of my Beverage antennas. The main change for this weekend was to increase the selectivity of the SDR radio to match the selectivity of the Icom 765. Consequently, I operated the entire contest exclusively receiving with the Beam Steering Rig (antennas, Softrocks, computer, keyboard and display). One adverse side effect of increasing the selectivity of the software radio was an increase in latency. In order to get a filter with more "taps" (DSP term), I had to increase the size of the buffers passed from the sound card driver to the rest of the software components. With the latency back at 21.3 milliseconds, I could no longer listen on both radios at the same time without going insane. Fortunately, the increased SDR selectivity allowed me to ignore the Icom 765, except for listening for Japan (and transmitting). The phased array antennas are broadside to a bearing of 67 degrees. As you steer the array away from broadside, the pattern gradually deteriorates. Past about 40 degrees off the bore-sight (a phased array term) the pattern degenerates to a lousy end-fire array (lousy because the spacing is not optimal). The poor performance occurs when the bearing is less than 27 degrees or greater than 107 degrees when switched east, and greater than 287 degrees or less than 207 degrees when switched west. Therefore, the array performs poorly when receiving Japan at a bearing of 330 degrees. Note that the sub-optimal performance is not much of a disadvantage for receiving the Caribbean and South America. So, to listen for Japan, I had to use the Beverages. Saturday morning was too noisy and I was too tired to pursue Asia. Sunday morning was less noisy, and conditions seemed to be better, although not good enough to work Japan. I heard JA3YBK peak at my sunrise, but he didn't last long enough to get past the other callers. In previous soapbox articles, I've complained about the lack of a receiver incremental tuning feature in the software radio (specifically, the SDR-Shell program which provides the user interface). I looked at the documentation again and noticed that there are keyboard commands to manipulate the filter boundaries (corresponds to pass-band tuning controls on a regular radio) and mouse gestures to control fine-tuning. I practiced these commands a bit during the weekend, and now I might be willing to retract my criticism. Nevertheless, a knob might still be more intuitive, since that is what I'm used to. On the other hand, since I used the software radio almost exclusively, I didn't have as many controls to operate. Conditions Friday night seemed poor while conditions Saturday night seemed to be good, although not as good as during the CQ 160 Test. Hopefully, the number of 200 watt and below Europeans that I worked is a testament to my technical prowess, and not just an artifact of conditions. Time will tell. I noticed that I worked more DX during the ARRL DX contest on 160 than in the CQ 160 contest. In that test, I worked 192 10-point QSOs and 8 non-Canadian 5-point QSOs for 200 DX QSOs. In this contest, I worked 214 DX QSOs. Is this a normal pattern? DX: 4U1U, 4X, 6Y, 8P, 9A (3), C6 (2), CM, CT, CT3, CX (2), DL (20), E7, EA (4), EA6 (2), EA8 (2), EI (2), ES, EU, F (12), G (24), GI (2), GJ, GM (3), GW (4), HA (3), HB, HB0, I (9), IS, J7, KH6 (3), KL, KP2 (4), KP4 (2), LA (2), LU, LX, LY (5), LZ (2), OE (2), OH (7), OK (17), OM (3), ON (2), OZ, P4, PA (6), PJ2 (2), PZ, S5 (3), SM (2), SP (6), SV (2), T32, UA (8), UR (4), V2, V3 (3), V4, VP5, VP6/d, VP9, YL (2), YO, YU (2), ZL, ZS (2). Missed UA2 and TI.